Splenic Capsule Research Articles

Laparoscopic versus Conventional Live Donor Nephrectomy: Experience in a Community Transplant Program

Fifty-nine consecutive patients underwent live donor nephrectomy for transplantation. Twenty-nine patients (Group I) had open kidney procurement, and 30 patients (Group II) had laparoscopic procurement. The mean operative time in Group I was 2:30 hours (range 1:55–2:59), whereas in Group II it was 3:01 hours (1:54–5:21). All kidneys functioned immediately after transplantation. The average warm ischemia time was not calculated in Group I; it was 3.9 minutes (2–15) in Group II. Intraoperative complications occurred in two patients in Group II. One patient had bleeding from an accessory renal artery. The second patient had a tear in the splenic capsule. No ureteral complications occurred in either group. Postoperatively one patient in Group I developed incisional hernia, one developed pneumothorax, and two developed atelectasis. In Group II one patient developed pancreatitis, one developed flank ecchymosis, and two had suprapubic wound hematomas. Using the laparoscopic approach the hospital stay decreased from 4.1 to 1.27 days (69%) ( P < 0.001) and return to work decreased from 28.4 to 14.8 days (49%) ( P < 0.01). Live donation increased by 67 per cent. We conclude that the laparoscopic procurement of kidneys for transplantation compares well with the open method. It offers several advantages that may increase the living donor pool.

Effects of chlorpropham (CIPC) on the hemopoietic system of rats

Male F344 rats were given 0 or 3% chlorpropham in the diet and at 2, 4, 6, 8 or 13 weeks of administration, five rats in each group were examined for hematology, plasma clinical chemistry and pathology. Marked splenomegaly and hepatomegaly were observed in treated rats at 2–13 weeks of administration. Red blood cell counts, hemoglobin concentration, packed cell volume and platelet counts were significantly decreased and methemoglobin level, mean corpuscular volume and white blood cell counts were significantly increased in treated rats at 2–13 weeks of administration. The covalent binding of m-chloraniline m-CA, (the hydrolytic metabolite of chlorpropham) was observed in hemoglobin or splenic protein of treated rats, but only small amounts of free m-CA were present in blood or spleen. Congestion, hemosiderin deposits, extramedullary hemopoiesis and lymphoid atrophy in spleen and hyperplasia of hemopoietic cells in bone marrow were observed in treated rats at 2–13 weeks and fibrosis in splenic capsule were observed in treated rats at 4–13 weeks. The pathological changes in spleen rather than hematological changes progressed during administration, suggesting splenotoxicity of CIPC in rats.

A new variant neuropathic type of Gaucher’s disease characterized by hydrocephalus, corneal opacities, deformed toes, and fibrous thickening of spleen and liver capsules

We report a new variant type of Gaucher’s disease characterized by hydrocephalus, corneal opacities, deformed toes, gastroesophageal reflux, and fibrous thickening of splenic and hepatic capsules. This patient had 1 D409H allele. He differed from other reported cases with a 1342G to C (D409H) homozygous mutation (onset at 4 months, no cardiac involvement until the age of 12 years, and massive hepatosplenomegaly with fibrous thickening of spleen and liver capsules). Enzyme replacement therapy was given for 4 years, resulting in an improvement of visceral and hematologic abnormalities but no neurologic improvement. (J Pediatr 2001;138:137-9)

Transitional Cell Carcinoma of the Urinary Bladder in a Thoroughbred, with Intra-abdominal Dissemination

A 14-year-old Thoroughbred gelding with a history of acute onset of hematuria was presented for necropsy. Transitional cell carcinoma of the urinary bladder with intra-abdominal dissemination was diagnosed. Tumor masses were observed on the splenic capsule and surrounding the distal abdominal aorta. Tumor cells showed diffuse cytoplasmic reactivity for cytokeratin but were negative for epithelial membrane antigen, carcinoembryonic antigen, tumor-associated glycoprotein 72, and vimentin.

Splenectomy for Splenic Metastases: A Changing Clinical Spectrum

Splenic metastases from solid tumors are unusual with only scattered case reports of patients treated with splenectomy before 1987. We conducted a retrospective chart review at our large tertiary-care private teaching hospital between January 1990 and September 1999 and found splenic metastases in 31 patients. In eight patients (26%), the spleen was the only site of metastatic disease. Of the 31 splenectomies for metastases, 23 were performed for ovarian neoplasms, five during primary operative procedures, and 18 during secondary cytoreductive procedures or explorations for late recurrences at an average of 3.9 years after the original operation. Nearly half of the metastases (15 of 31) appeared entirely within the splenic parenchyma, representing probable hematogenous spread, whereas seven involved both the splenic parenchyma and capsule and nine involved the capsule only. Between 1990 and 1999 we identified a statistically significant increase in use of splenectomy for treatment of metastatic tumor with a Spearman rank correlation value of 0.86 (P < 0.05). Most of this increase was attributable to ovarian cancer cases and may be due to expansion of treatment options or improved imaging methods. We report the largest series of splenectomy for splenic metastases and the ninth case report in the world literature of splenectomy for isolated splenic metastasis due to colorectal cancer.

Metastatic tumors to the spleen: a 25-year clinicopathologic study.

The clinicopathologic features of splenic metastases have seldom been investigated. The aim of this study was to evaluate the clinical and pathological impact of splenic metastases. We reviewed the clinical/autopsy records and pathologic features of 92 Chinese patients (58 men, 34 women) with secondary nonlymphoid splenic tumors recorded during a 25-year period. The incidence of splenic secondary tumors at autopsy was 0. 6% and at splenectomy, 1.1%. The lesions were often seen in elderly patients (mean age, 60 years). Seven (8%) of the splenic lesions were symptomatic. The symptomatic splenic lesions, as compared with asymptomatic lesions, were bigger and were found more often in women and younger patients. Two patients experienced spontaneous splenic rupture because of metastatic carcinoma. Eighty-seven (95%) of the secondary splenic tumors were carcinomas. Lung was the most common primary tumor site (21%), followed by the stomach (16%), pancreas (12%), liver (9%), and colon (9%). Rarely reported sources of primary tumor, such as esophageal carcinomas, nasopharyngeal carcinoma, and choriocarcinoma, were also found. Splenic metastases could be identified macroscopically in 74 (80%) of our patients. Grossly, splenic metastases involved the splenic capsule (n = 8) or were solitary (n = 31), multiple (n = 30), or diffuse (n = 8) lesions in the splenic parenchyma. Isolated splenic metastases were noted in 5.3% of the metastases found at autopsy. Many of the metastatic lesions in the spleen were identified shortly after primary tumors were detected (mean latent period, 6.7 months). The time from diagnosis of the primary tumor to metastasis to the spleen was more than 2 years in 14 patients. Splenic metastases are uncommon. A variety of clinical and pathologic patterns were noted in our series.

Laparoscopic splenectomy in a rat model: developing an easy technique.

Laparoscopic surgery in small-animal models provides insight into basic physiopathological aspects of laparoscopy. However, laparoscopic work in small animals entails precise skill and long operative times. We present an easy and shorter three-trocar procedure (two of 5 mm and one of 2 mm) for splenectomy in a rat model. Miniature instruments (2-mm forceps, 3-mm endoscope, and 5-mm endoapplier) were used. Forty laparoscopic splenectomies were attempted. The operative time was 30 +/- 4 minutes. There was no postoperative mortality, and scintigraphy ruled out the presence of residual splenic tissue. Laparoscopic splenectomy in a rat is feasible. When using experimental laparoscopic models for splenectomy, an easy technique is of great importance in order to avoid cumbersome manuevers that can cause rupture of the splenic capsule and cell spillage or postoperative bleeding. The development of surgical laparoscopic instruments with thinner devices (5-mm endoclip appliers and 2-mm ports and instruments) facilitates the procedure and permits a significantly shorter operative time.

Conversion factors for laparoscopic splenectomy for immune thrombocytopenic purpura.

Since 1994, 27 patients at our institution have undergone laparoscopic splenectomy for immune thrombocytopenic purpura (ITP). Laparoscopic splenectomy was completed in 22 of these patients. We sought to identify factors that precluded successful laparoscopic splenectomy in the remaining 5 patients. Retrospective review of 27 patients with ITP undergoing laparoscopic splenectomy was performed at Duke University Medical Center from August, 1994 to September, 1997. Laparoscopic splenectomy was performed in 16 women and 11 men with a mean age of 47.2 years. Five (18%) of these procedures were converted to open splenectomy. There was no significant difference in age, ASA score, gender, weight, height, or splenic size between the converted and laparoscopic groups. However, preoperative and postoperative platelet counts were significantly higher in the laparoscopic group than in the converted group (p < 0.001). Operative times also were significantly longer for the laparoscopic group than for the converted group (p < 0.001). Adherent adjacent structures, associated comorbidities, and technical errors prohibited laparoscopic completion in five patients. Technical errors with subsequent bleeding required conversion in two patients. A thickened greater omentum blanketing the splenic capsule and a densely adherent pancreatic tail extending well into the splenic hilum prevented laparoscopic completion in two patients. Increased peak airway pressures greater than 60 mmHg after pneumoperitoneum necessitated conversion in the remaining patient, who had a previous history of pulmonary insufficiency. Regardless of surgical approach, all patients achieved a therapeutic response after splenectomy. Splenectomies completed laparoscopically resulted in a significantly shorter length of hospital stay (p < 0.01). Densely adherent adjacent structures, technical errors, and cardiopulmonary instability may preclude successful completion of laparoscopic splenectomies. Thorough preoperative evaluation with an emphasis on the cardiopulmonary system may elicit a cohort of individuals with ITP who are unlikely to undergo laparoscopic splenectomy successfully. This cohort also may include individuals with preoperative platelet counts less than 35,000 mm(-3).

Laparoscopic hepatic lobectomy in the porcine model.

To date, there have been only a few anecdotal reports of laparoscopic hepatectomy, most of which are limited to wedge resections. The aim of this study was to assess the feasibility of laparoscopic hepatic lobectomy in a porcine model. Eight pigs were anesthetized before placement of an abdominal wall lift device and five laparoscopic ports. With the porta hepatis clamped, the left lateral hepatic lobe was divided with an ultrasonic dissector. Small vessels and ducts were clipped, larger vascular structures were transected with staplers, and surface hemorrhage was controlled with an argon beam coagulator. Serum liver enzymes (LFTs) and blood counts were drawn pre- and postoperatively. All animals were killed after 1 week. Mean +/- SEM operating and clamp times were 131 +/- 8 and 39 +/- 2 min, respectively. There were four intraoperative complications in three animals (three lacerations of the hepatic vein and one tear of the splenic capsule), all of which were controlled at surgery. Mean blood loss was 189 +/- 52 ml, and the mass of the resected specimen was 139 +/- 11 g. There were no postoperative complications or deaths. White blood cell count, hematocrit, and LFTs did not change postoperatively, except for aspartate aminotransferase (AST), which was elevated transiently. There were no bile leaks or intraabdominal abscesses. Laparoscopic left hepatic lobectomy was technically feasible in the porcine model using an abdominal wall lift device for exposure. Clinical trials are needed to assess its feasibility and limitations before laparoscopic hepatic lobectomy is deemed safe for human use.

Delayed splenic rupture complicating laparoscopic cholecystectomy - case report and review

SummaryLaparoscopic cholecystectomy is well established as the preferred surgical treatment In patients with uncomplicated cholelithiasis. Although morbidity and mortality are low, major complications occasionally occur. We report a case of delayed splenic rupture complicating an otherwise uneventful laparoscopic cholecystectomy. The aetiology was disruption of the splenic capsule by traction on perisplenic adhesions caused by use of the pneumoperitoneum or occurring during removal of the gall bladder through the epigastric port. Delayed splenic haemorrhage is a potential complication for any patient undergoing laparoscopic surgery and should be considered if a patient develops signs of bleeding post-operatively.

An atraumatic technique to fix the omentum after partial splenectomy.

During a partial splenectomy, the resultant bleeding of the remaining spleen is difficult to control; some techniques have been described to achieve complete hemostasis. The omentum has been traditionally used to promote hemostasis on raw surfaces of solid viscus, particularly during the repair of liver injuries. We present here a technique to fix the omentum to the spleen after partial resections; emphasis is made to perform it in an atraumatic way to avoid additional damage to the splenic capsule.

Changes in splenic volume after partial splenic embolization in children

Aim: The authors studied changes in splenic volume after partial splenic embolization (PSE) in children who had thrombocytopenia caused by splenomegaly. Materials and Methods: Five children with hypersplenism (ages of 1, 6, 7, 10, and 14 years) underwent PSE. The follow-up period ranged from 1 month to 8 years 9 months. Whole and infarcted splenic volumes were measured from computed tomography images obtained before and after PSE. Results: Within 2 weeks after PSE, the whole splenic volume increased to 110% to 140% of the pre-PSE volume. The infacted area disappeared 3 to 4 months after PSE, and the whole splenic volume decreased markedly. The decreased volume tended to be stable during the follow-up period. The splenic enlargement before PSE ranged from 7.2 to 14.2 times the standard splenic volume for a corresponding body weight. The splenic volume did not become normal after PSE; it remained between 2 and 7 times larger than standard. Platelet counts stayed above 10 × 10 4/mm 3 when the splenic volume reduced to 2 times the standard volume. Conclusion: The first 4 weeks after PSE is the most dangerous period for the development of splenic rupture because of marked expansion of the splenic capsule. The infarcted parenchyma is absorbed 3 to 4 months after PSE, and the whole splenic volume is reduced. Thereafter, the splenic volume is stable for several years. Reembolization is not likely to be necessary in the majority of patients who have had splenic embolization with an infarction rate of ≥80%.

Lymphangiomatous hamartoma of the spleen

A 72 year old female was admitted for an operation of gastric cancer. At the operation, a 3 x 3 cm-sized, whitish and multilocular nodule was incidently found at the left side of the spleen. This nodule was adjoining the splenic capsule and was characterized with sparsely found multilocular lymphatic cysts with varying sizes. The walls of these cysts were composed of partly thin fibrous tissue, or partly thin to thick splenic trabeculae. Abnormally elongated, nodular or fragmentary trabeculae were also present in the nodule. White and red splenic pulp was found widely dispersed among the cysts. The surrounding splenic tissue was not compressed. We considered the essence of this tumor to be an abnormal mixture of normal splenic elements such as lymphatics, splenic trabeculae, and red and white pulp, and regarded this tumor as a focal malformation (lymphangiomatous hamartoma) rather than a true neoplasm such as a lymphangioma.

Endotoxin induces parathyroid hormone-related protein gene expression in splenic stromal and smooth muscle cells, not in splenic lymphocytes.

PTH-related protein (PTHrP), the peptide that is responsible for most cases of hypercalcemia of malignancy, is also produced under normal circumstances by a variety of tissues. Its role and regulation at these sites are not well understood. Recently, we have shown that PTHrP is induced in the spleen during the host response to endotoxin (LPS) and that tumor necrosis factor (TNF) is a major mediator of this effect. Given the large body of in vitro evidence suggesting that PTHrP can be produced by lymphocytes and act in an autocrine loop to alter their function, studies were undertaken to determine whether lymphocytes were the cells responsible for PTHrP production in the spleen. Both constitutive and LPS-induced PTHrP messenger RNA (mRNA) levels were the same in mice lacking mature T cells (nude mice) and in mice lacking natural killer (NK) cells (due to pretreatment with antibody against NK 1.1) compared to levels in normal mice, suggesting that neither mature T cells nor NK cells were the splenic source of PTHrP. Even scid mice that lack functioning T and B cells responded to TNF with the induction of splenic PTHrP mRNA levels comparable to those in control mice. Localization of PTHrP mRNA in subfractions of rat spleens after in vivo treatment with LPS confirmed the results of the murine studies; PTHrP mRNA was barely detectable in the lymphocyte-rich single cell fraction of the spleen. In contrast, the stromal fraction of the spleen was enriched with PTHrP mRNA both in the basal state and in response to LPS. A similar pattern of distribution was seen for interleukin-6; LPS only increased mRNA levels of this TNF-inducible cytokine in the splenic stroma. In addition, mRNA for the PTH/PTHrP receptor, which decreased in response to LPS, colocalized with PTHrP mRNA in the stromal fraction of the spleen. Immunohistochemical studies identified PTHrP in two populations of splenic cells: 1) smooth muscle cells located in the splenic capsule and trabeculae and 2) a subpopulation of stromal cells located in the red pulp of the spleen, primarily in a subcapsular distribution. Consistent with the localization of PTHrP mRNA, lymphocytes in the white pulp of the spleen did not stain for PTHrP.

Characterisation of functional endothelin receptors in the canine isolated perfused spleen

The endothelin receptor subtypes involved in the vasoconstriction, capsular smooth muscle contraction, prostaglandin E 2 and prostacyclin release induced by endothelin-1 have been investigated in the canine isolated perfused spleen using both the endothelin ET A receptor antagonist FR 139317 and the endothelin ET B receptor agonist IRL 1620. The isolated canine spleen was perfused with warmed (37°C) and oxygenated (95% O 2/5% CO 2) Krebs solution at constant flow with continuous recording of splenic arterial perfusion pressure and spleen weight. Samples of splenic venous effluent were collected to determine the amounts of prostaglandin E 2 and prostacyclin, measured by radioimmunoassay. Endothelin-1 (4–200 pmol) and IRL 1620 (20–1000 pmol) dose-dependently increased splenic arterial perfusion pressure but the former was more potent on a molar basis (the molar dose ratio IRL/endothelin-1 required to increase splenic arterial vascular resistance by 25% was approximately 33). The infusion of the nitric oxide inibitor N ω-nitro- l-arginine methyl ester (10 μM), but not of the enantiomer N ω-nitro- l-arginine methyl ester, significantly potentiated the increase in splenic arterial vascular resistance induced by endothelin-1. The infusion of FR 139317 (1 μM) markedly attenuated the increased splenic arterial perfusion pressure induced by endothelin-1 without affecting that evoked by IRL 1620. At the highest dose (200 pmol), endothelin-1 induced a small but significant capsule contraction as reflected by the reduction in the spleen weight. The infusion of FR 139317 (1 μM) abolished this contractile effect. IRL 1620 (in doses up to 1000 pmol) did not significantly affect the capsule tone. The administration of either endothelin-1 (20–200 pmol) or IRL 1620 (20–1000 pmol) caused the release of 6-oxo-prostaglandin F 1α (breakdown product of prostacyclin) and prostaglandin E 2 into the splenic venous effluent. The amount of both prostanoids released by endothelin-1 was significantly greater than that induced by IRL 1620. FR 139317 (1 μM) significantly reduced ( P < 0.05) the release of both 6-oxo-prostaglandin F 1α and prostaglandin E 2 by endothelin-1 without affecting that released by IRL 1620. The results demonstrate that the release of prostaglandins and nitric oxide modulates the vasoconstrictor activity of endothelin-1 in the splenic circulation. Furthermore, the vasoconstriction and eicosanoids (prostacyclin and prostaglandin E 2) release by endothelin-1 are due to activation of both endothelin ET A and ET B receptors, although the former seems to be the predominant form. The splenic capsule contraction is mediated by activation of endothelin ET A receptors only.

Emergency treatment of asthma.

The cholinergic component in the sympathetic innervation to the spleen was studied in dogs. This was accomplished by the use of hemicholinium (HC-3) to inhibit transmission in the chohinergic nerves and the use of reserpine and guanethidine to inhibit adrenergic function. The spleen responded normally to electrical stimulation of the splenic nerve at a time when cholinergic transmission was inhibited. These data support the concept of separate chohimiergic and adrenergic fibers in the splenic nerve rather than a cholinergic junction in the adrenergic fibers. The relationships between the cholinergic and adrenergic components associated with the splenic nerve were studied further by the use of acetylcholine and nicotine. Both of these components of this nerve were found to be involved in both the responses to nicotine and in a possible mechanism for the control of the tone of the splenic capsule. These data are dliscussed in relation to the hypothesis of local chohinergic-adrenergic interaction.

Evaluation of Polydimethylsiloxane as an Alternative in the Endoscopic Treatment of Vesicoureteral Reflux

Endoscopic correction of vesicoureteral reflux is an attractive alternative to open repair. In terms of effectiveness and long-term successful results polytetrafluoroethylene (Polytef) is the most reliable injectable product. However, legitimate concerns regarding particle migration still exist for polytetrafluoroethylene. Polydimethylsiloxane (Macroplastique) was evaluated as an alternative to polytetrafluoroethylene. Seven mongrel female dogs underwent endoscopic suburothelial injections of 0.35 to 0.50 cc polydimethylsiloxane paste by the O’Donnell technique to a unilateral nonrefluxing ureteral orifice. To facilitate migratory surveillance the paste was mixed with 57carbon monoxide radiolabeled 80pm. microspheres and injected in 5 of the 7 animals. Animals were sacrificed at 1, 3 and 6-month intervals. All major organs were retrieved and processed.After intensive histological evaluation the remaining tissue underwent dissolution and centrifugation in sodium hypochlorite. The resulting insoluble pellet was further analyzed. In dogs injected with radiolabeled paste tissue samples and insoluble pellets of each organ system were analyzed for y counts. Smears of the insoluble pellets of all animals were examined on light and phase contrast microscopy. At autopsy no gross abnormalities were noted. Tissue reaction at injection sites revealed a well encapsulated foreign body reaction with predominantly giant cells, fibroblasts and collagen deposition.Limited local migration of polydimethylsiloxane particles into the periureteral lymphatics of 1 animal sacrificed at 1 month was noted and a single particle visually indistinguishable from polydimethylsiloxane also was found within the splenic capsule. The endoscopic procedure in this animal was complicated in that 2 separate injections were required and histological evaluation confirmed that the injections were performed uniquely deep into the bladder muscularis. Radioactive counts and dissolution of all major organ systems demonstrated no migration in the remaining 6 animals. Endoscopic subureteral injection of polydimethylsiloxane is technically feasible, and it may prove to be biocompatible and without risk of distant migration if injected correctly.

Short-Term Toxicity of Bitumen Upgrading Products in the Rat Following Repeated Dermal Exposure

Short-Term Toxicity of Bitumen Upgrading Products in the Rat Following Repeated Dermal Exposure. Poon, R., Chu, I., Villeneuve, D.C., and Valli, V. E. (1994). Fundam. Appl. Toxicol. 23, 237-250. Light gas oil (B-LGO), heavy gas oil No. 1 (B-HGOI), and heavy gas oil No. 2 (B-HGOII) fractions of bitumen upgrading products (BUPs) were applied on the dorsal skin of rats at 25 mg/kg bw/day (low dose), 100 mg/kg bw/day (intermediate dose), and 400 mg/kg bw/day (high dose) for 4 weeks. Control animals received normal saline while positive controls received a medium boiling coal liquefaction product (CLP) at 100 and 400 mg/kg bw/day. Reduced food consumption and growth suppression were observed in males and females treated with B-HGOI, B-HGOII, and CLP, but only in males receiving B-LGO. Increased relative spleen, kidney, and liver weights were observed in animals treated with B-HGOI, B-HGOII, and CLP, but not in control or LGO groups. A dose-related increase in absolute and relative liver weight was most marked in animals receiving B-HGOII where a significant increase was observed starting at the low dose, followed by those receiving B-HGOI and CLP. Appearance of pale foci on the splenic capsule and increases in spleen/body weight ratio were limited to animals receiving B-HGOI and B-HGOII. Decreases in hematocrit and RBC and increase in percentage of reticulocytes were observed in animals of both sexes receiving B-HGOI and B-HGOII. Female rats appeared to be more severely affected because significant decreases in hemoglobin and RBC were observed in animals receiving the low dose of B-HGOII and the intermediate dose of B-HGO-I. Increased serum cholesterol was observed in B-HGOII-treated females at all dose levels, and in males starting at the intermediate dose. Histological changes were observed in the thymus gland, where moderate to marked cortical atrophy was noted in male and female rats receiving the high dose of B-HGOI and B-HGOII, and in the bone marrow, where the most significant abnormality was the presence of focal myelofibrosis in some male rats treated with B-HGOI and B-HGOII. Mild to moderate histological changes were found in the thyroid, liver, and spleen of rats of all treatment groups. Changes in the skin included moderate hyperkeratosis in females receiving high doses of B-LGO and in animals of both sexes receiving high doses of B-HGOI, and moderate to marked epidermal hyperplasia in rats receiving high doses of B-HGOI. Based on these multiple endpoints, the severity of systemic toxicity was B-HGOII > B-HGOI > CLP ⩾ B-LGO. The NOEL was about 25 mg/kg bw/day for B-LGO and lower than 25 mg/ kg bw/day for B-HGOI and B-HGOII.

Generation of 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[ a]pyrene by murine splenic macrophages

Studies have demonstrated that macrophages are the cell types which metabolize benzo[ a]pyrene (B[ a]P) within the murine spleen. B and T cells, polymorphonuclear cells, or the splenic capsule did not produce amounts of B[ a]P metabolites above those of background. Exposure of mice to B[ a]P, a known inducer of isozymes of cytochrome P450, resulted in an increase in the amounts of some B[ a]P metabolites generated by macrophages. Evaluation of the in vitro plaque-forming-cell response to several T-cell and macrophage-dependent antigens following in vivo exposure to B[ a]P indicated that the macrophage is the cell type responsible for B[ a]P-induced immunosuppression. While suggestive, the reported data have not definitively established that an enriched splenic macrophage population can generate 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-B[ a]P (BPDE) from B[ a]P-7,8-dihydroxy-7,8-dihydrodiol (B[ a]P-7,8-diol). These data are critical to our hypothesis that the splenic cell type(s) which from BPDE will be the primary target cell responsible for B[ a]P-induced immunosuppression. The first objective was to determine if splenic macrophages could generate BPDE. Enriched (80–90% purity) populations of macrophages were incubated with [ 3H]B[ a]P for 24 hr. BPDE generated was quantitated by analysis of the cis- and trans-tetrol hydrolysis products of BPDE via HPLC procedures. Splenic macrophages generated BPDE from B[ a]P. The cis syn was the predominate tetrol detected. Exposure of mice to B[ a]P increased the amounts of the trans-anti-tetrols 2.2-fold, the trans-syn-tetrols 2.0-fold, the cis-anti-tetrols 1.8-fold, and the cis-syn-tetrols 2.6-fold above those formed by macrophages of vehicle-exposed mice. Both cytochrome P450- and peroxyl radical-dependent pathways are known to oxidize B[ a]P-7,8-diol to BPDE. Since macrophages were found to generate BPDE, the second objective was to investigate which enzymatic pathway was responsible for its formation. The B[ a]P-(+)-7,8-diol isomer has been shown to produce different specific BPDE isomers via the cytochrome P450 and peroxyl radical pathways. Macrophage populations were incubated with [ 3H]B[ a]P-(+)-7,8-diol for 24 hr and the contribution of the cytochrome P450 and peroxyl radical pathways to BPDE formation determined by detection of syn-BPDE-hydrolysis and anti-BPDE-hydrolysis products, respectively. Based on the ratio of anti/syn BPDE-derived tetrol products, the results demonstrate that splenic macrophages can generate the BPDE by both a cytochrome P450-dependent and -independent (peroxyl radical) pathway. Macrophages are the cells which metabolize B[ a]P within the murine spleen and may be the cell type responsible for B[ a]P-induced suppression of humoral immune responses.

Histopathologic changes of the spleen in suckling rats inoculated with Hantaan virus.

The purpose of this study is to delineate the histopathologic findings of the spleen after Hantaan viral inoculation, which is the largest lymphoid organ in rats, and to identify the viral location by anti-Hantaan virus (HTNV) monoclonal antibody. All the sixty one suckling rats of less than twenty four hours of age were used. Except twenty one rats of control group, twenty-five rats inoculated intracerebrally for the early change and fifteen suckling rats inoculated intramuscularly for the late change were uniformly susceptible to lethal infection with the ROK 84-105-1 strain of seed HTNV. The characteristic histopathologic findings were; appearance of macrophages below the splenic capsule on the 3rd day, small lymphocytes around the periarteriolar sheath on the 5th day increasing in numbers on the 7th day, and a markedly expanded marginal zone with some immunoblasts and plasma cells as well as decreased extramedullary hematopoiesis on the 9th and 14th days. Time of onset of histopathologic changes in spleen thickness, appearance of medium and large lymphocytes and degree of extramedullary hematopoiesis were influenced by inoculation route, whereas expansion of the marginal zone was affected by postnatal age.