Cardiovascular effects of acute hypercholesterolemia in rabbits. Reversal with lovastatin treatment.

Hypercholesterolemia was induced in New Zealand white rabbits by feeding them a 0.5% cholesterol-enriched rabbit chow for 2 wk. Half of the cholesterol-fed rabbits were given lovastatin, a potent inhibitor of hydroxymethylglutaryl-coenzyme A reductase (HMG-CoA reductase), the rate limiting enzyme in cholesterol biosynthesis, and the other half were given its vehicle (i.e., DMSO). At the end of 2 wk, the rabbits underwent experimental myocardial ischemia or a sham ischemia procedure. Ischemic animals fed the cholesterol-enriched diet for 2 wk experienced much greater cardiac damage than ischemic rabbits fed the control diet, despite the absence of any atherosclerosis. Lovastatin was shown to protect the ischemic rabbit myocardium by three different indices of ischemic damage: (a) maintenance of creatine kinase (CK) activity in the ischemic myocardium; (b) reduced loss of free amino-nitrogen containing compounds from the ischemic myocardium; and (c) blunting the rise of plasma CK activity. These effects were not due to differences in myocardial oxygen demand between the groups. Arteries isolated from animals fed the cholesterol-enriched diet developed defects in endothelium-dependent relaxation in both large vessels as well as coronary resistance vessels. Acute hypercholesterolemia increases the severity of myocardial ischemia while at the same time impairing endothelium-dependent relaxation. These deleterious changes can be significantly attenuated by treatment with lovastatin.

Beneficial effects of a specific leukotriene receptor antagonist in splanchnic artery occlusion shock.

The purpose of this study was to examine the effects of a new potent peptidoleukotriene receptor antagonist, SK&F 104353, in splanchnic artery occlusion shock. SK&F 104353 was administered as a 1 mg/kg initial bolus followed by an infusion of 3 mg/kg per h for the entire 2 h post-reperfusion observation period. In a group of conscious rats, this dose of SK&F 104353 shifted the LTD4 dose response curve rightward 10-fold, indicating effective antagonism of peptidoleukotriene responses in the rat. Anesthetized rats subjected to splanchnic artery occlusion shock survived an average of only 98 +/- 8 min whereas all animals receiving SK&F 104353 survived the 2 h reperfusion period (P less than 0.02 from vehicle). Therefore, the survival rate of the splanchnic artery occlusion shock group of rats receiving SK&F 104353 was improved to 100% compared with 50% survival for the vehicle-treated splanchnic artery occlusion shock group (P less than 0.025). In the splanchnic artery occlusion shock + SK&F 104353 group the increase in the plasma activities of the lysosomal hydrolase, cathepsin D, and the cardiotoxic peptide, myocardial depressant factor, were significantly attenuated in comparison to the splanchnic artery occlusion shock + vehicle group (P less than 0.025). These data indicate that the peptidoleukotriene receptor antagonist, SK&F 104353 is beneficial in splanchnic artery occlusion shock, and furthermore suggests that it may be a therapeutically useful agent in bowel ischemic shock.

Production and characterization of monoclonal antibodies against the ribosome inactivating proteins dianthin32 and momochin.

Female BALB/c mice were immunized with either dianthin32 or momochin, type 1 ribosome-inactivating proteins (RIPs) derived from Dianthus charyophyllus and Momordica cochinchinensis, respectively. Five anti-dianthin32 and 6 anti-momochin secreting hybridomas were obtained by somatic fusion of lymphocytes with myeloma cell line NS0. The monoclonal antibodies (MAbs) produced were highly specific, as demonstrated by cross-reactivity assays performed with taxonomically related and unrelated type 1 RIPs, and recognized different epitopes of the antigen. The affinity constant of anti-RIPs MAbs ranged between 10(8) M-1 and 10(10) M-1.

Meniscal injuries: A critical review.

Although once perceived as an unimportant vestigial structure, the menisci of the knee are now known to be a common source of knee pain and disability. The medial meniscus is more vulnerable to injury to due to its intimate attachment to the medial collateral ligament. The moveable lateral meniscus is less prone to tear except when the ACL is injured. The medial and lateral menisci are usually injured as a result of sudden knee flexion with a component of knee internal or external rotation. However, older patients may present without a specific mechanism of injury as their meniscal injuries are often due to degenerative processes. Most meniscal injuries can be diagnosed with a thorough physical examination utilizing the McMurray, Apley, and ``bounce home'' maneuvers. Joint line tenderness and the presence of a knee effusion aid in the diagnosis. Magnetic Resonance Imaging (MRI) has become the test of choice in confirming injury. MRI also defines the type, location, and severity of meniscal injury. Some meniscal injuries, particularly peripheral, well-vascularized tears, may be more prone to healing with nonsurgical management. Typical initial management includes reduction of swelling and pain. Rehabilitation stresses tri-planar functional retraining. The final phases of rehabilitation incorporate a functional progression to sports or work specific activities. Arthroscopic knee surgery has become a prevalent treatment method for bucket handle tears and non-vascularized meniscal injuries. Meniscal repair is currently preferred over partial menisectomy to avoid premature osteoarthritis. In sum, clinicians can return patients with meniscal pain to a high level of function with appropriate recognition of injury and functional rehabilitation.

Beneficial mechanisms of action of a prostacyclin enhancing agent in splanchnic artery occlusion shock.

Defibrotide stimulates PGI2 production and exerts significant antithrombotic, fibrinolytic and plasminogen-activating activities. We studied its effects in splanchnic artery occlusion (SAO) shock in rats. Anesthetized rats subjected to total occlusion of the celiac and superior mesenteric arteries for 40 minutes developed a severe shock state following reperfusion usually resulting in death 90-120 minutes after releasing the clamps. Defibrotide 910 mg/kg +25 mg/kg/h) treated SAO shock rats maintained higher post-reperfusion mean arterial blood pressure compared to those receiving only the vehicle (0.9% NaCl). SAO shock rats treated with defibrotide exhibited lower plasma activities of the lysosomal protease cathepsin D (p less than 0.05 from vehicle) and myocardial depressant factor (p less than 0.02 from vehicle) as well as the plasma accumulation of free amino-nitrogen compounds (p less than 0.05 from vehicle). All SAO shock rats treated with defibrotide survived the entire 120 post-release period compared with only a 42% survival rate for rats receiving only the vehicle (p less than 0.02). These results suggest a remarkable protective effect of defibrotide in SAO shock.

Detection of platelet-activating factor during traumatic shock.

The purpose of this study was to determine if platelet-activating factor (PAF) is formed in the peritoneal fluid of rats following traumatic shock. Anesthetized rats subjected to Noble-Collip drum trauma developed a lethal shock state characterized by a mean survival time of 80 +/- 16 min and a final mean arterial blood pressure of 54 +/- 7 mm Hg compared with 117 +/- 14 mm Hg in sham-shock control rats. Peritoneal fluid from traumatized and PAF-infused rats analyzed by high performance liquid chromatography (HPLC) contained a phospholipid which had a similar retention time as authentic PAF, but was absent in sham shock rats. Furthermore, aliquots of this chromatographic peak aggregated washed rabbit platelets, and the aggregation was blocked by a specific PAF receptor antagonist, CV-6209. Moreover, extraction of peritoneal fluid from traumatized rats aggregated washed rabbit platelets and this activity increased nearly four-fold in traumatized rats compared to sham shock rats. These findings are consistent with the formation of PAF in traumatic shock, and along with previous data of PAF antagonists ameliorating traumatic shock, support a role of platelet-activating factor in the pathogenesis of traumatic shock.

The distribution of Lewy bodies in pure autonomic failure: autopsy findings and review of the literature.

Pure autonomic failure (PAF; also known as idiopathic orthostatic hypotension or Bradbury-Eggleston syndrome) is an uncommon sporadic disorder, characterized by autonomic failure without other neurological deficits and histopathologically by cell loss in intermediolateral columns and sympathetic ganglia. Few postmortem studies of patients with PAF have been reported in the literature, and none have demonstrated Lewy bodies in distal axons, although this has been described as a feature in Parkinson's disease with autonomic failure. We report a patient with PAF who had orthostatic hypotension and urinary symptoms for 15 years prior to death at the age of 63 years. Postmortem findings included typical and atypical Lewy bodies in the substantia nigra, locus ceruleus, substantia innominata, and sympathetic ganglia, as well as in autonomic axons in the epicardial fat, autonomic nerve fascicles in periadrenal adipose tissue, and autonomic nerves in the muscularis of the urinary bladder. Sites of autonomic nerve involvement correlated with clinical symptomatology, and thus were a valuable observation in the complete autopsy. Systemic autopsy results should be reviewed carefully in patients with PAF, as Lewy bodies in this disease may be seen in distal axons at a great length from their primary cell bodies.

Different cytotoxic activity and intracellular fate of an anti-CD5-momordin immunotoxin in normal compared to tumour cells.

We investigated the different sensitivity of peripheral blood mononuclear cells (PBMC) and human T cell leukaemias (Jurkat and CEM) to an anti-CD5-momordin immunotoxin. In a short-term assay, the immunotoxin displayed different cytotoxic activity on normal and tumour cells: for leukaemic cell lines an incubation time of 72 h was necessary for the immunotoxin to reach the IC50 of 41-53 pM, compared to the 1 h sufficient for 6 pM immunotoxin to inhibit 50% of PBMC protein synthesis. In a long-term clonogenic assay (15 days), the immunotoxin demonstrated a comparable efficacy of clonogenic cell killing for both cell types. We investigated the immunotoxin internalization pathway by a flow-cytometric method and our data seem to indicate that the molecules meet a different intracellular fate in the two cell populations. It may be assumed that the low cytotoxic activity of immunotoxins on tumour cells, detected in the short-term assay, is due to inefficient delivery to their cytoplasmatic target, while a longer exposure of the cells to the immunotoxin promotes adequate intracellular distribution.

Feasibility of pathological evaluation of morcellated kidneys after radical nephrectomy.

PURPOSE: The indications for laparoscopic nephrectomy have grown to include renal malignancy. Although morcellation of these specimens has been described, to our knowledge we present the first systematic review of the feasibility and validity of pathological evaluation of these tumors with regard to grade and stage. MATERIALS AND METHODS: Nine formalin fixed and 5 fresh intact radical nephrectomy specimens were evaluated by 2 pathologists before and after high speed electrical tissue morcellation. The ability to distinguish tissue histology, and tumor size, stage and grade were compared. Impermeability of the laparoscopy sack after morcellation was also evaluated using indigo carmine stained normal saline placed in the used sack. RESULTS: The 9 preserved specimens included 7 renal cell carcinomas and 2 oncocytomas, while 4 of the 5 fresh specimens were renal cell carcinoma and 1 was oncocytoma. Overall tumor size was 2 to 7 cm. (mean 4.9). The 4 fresh renal cell carcinomas were of the clear cell type. Comparison of pathological evaluation after morcellation by another pathologist revealed identical histology, grade and stage for each tumor. Four cases of perinephric fat invasion (3 fixed and 1 fresh specimens) were identified after morcellation. Only tumor size was not assessed after morcellation. Laparoscopy sack integrity was confirmed in 13 of 14 cases. In 1 case involving a formalin fixed specimen a gross defect in the laparoscopy sack was demonstrated after morcellation. CONCLUSIONS: Morcellation of radical nephrectomy specimens in vitro did not alter the determination of histology, grade or local invasiveness of tumor. For all fresh tissue and remarkably for all but 1 formalin fixed tissue specimen the laparoscopy sack remained intact. Preliminary data from this in vitro model imply that limited in vivo morcellation of radical nephrectomy specimens may be performed without sacrificing staging information.

In vitro and in vivo properties of an anti-CD5-momordin immunotoxin on normal and neoplastic T lymphocytes.

An anti-CD5 monoclonal antibody (mAb) was linked to the plant toxin momordin, a type-1 ribosome-inactivating protein purified from Momordica charantia. The in vitro cytotoxicity of the immunotoxin was evaluated as the inhibition of protein and/or DNA synthesis on isolated peripheral blood mononuclear cells (PBMC) and on human T cell leukemia Jurkat. The potency of the immunotoxin on PBMC was very high (IC50 = 1 - 10 pM) and was not affected by blood components. The conjugate was also very efficient in the inhibition of the proliferative response in a mixed lymphocyte reaction (IC50 = 10 pM). Moreover, the in vitro performance of the immunotoxin compared favorably with those reported for other anti-CD5-based immunoconjugates containing ricin A chain. The in vivo activity of the immunotoxin was assessed in the model of nu/nu mice bearing Jurkat leukemia. A significant inhibition of the tumour development (80%, P < 0.01) in the animals treated with immunotoxin was observed. Taken together, the in vitro and in vivo results suggest that the anti-CD5-momordin conjugate may be useful for graft-versus-host disease therapy and potentially in the treatment of CD5-positive leukemias and lymphomas.

Diaminic carbonates, a new class of anti-inflammatory compounds: their biological characterization and mode of action.

Taking advantage of a standard assay on mouse LM cells (murine fibroblast-like cells), we found that several diaminic carbonates, a new class of organic compounds synthesized in our laboratories, were able to inhibit human tumor necrosis factor alpha (huTNFalpha)-induced cytotoxicity in a dose-dependent manner. Structure-function relationship studies indicated precise structural requirements for compounds being active as huTNFalpha inhibitors. ITF1779, one of the most active compounds in inhibiting huTNFalpha-induced cytotoxicity, was selected for further studies. In vitro experiments showed that ITF1779 inhibited not only huTNFalpha-induced cytotoxicity on LM cells but also another response of the same cells, interleukin-1-induced interleukin-6 production. Receptor-binding studies performed under nonequilibrium conditions and morphologic evidence of vacuole formation in cells treated with high concentrations of ITF1779 showed that the effects were strikingly similar to those of chloroquine, a lysosomotropic agent. Consistent with a mechanism of action of diaminic carbonates closely matching that of chloroquine are some structural similarities between the two classes of compounds, in particular their both being diprotic weak bases. Moreover, ITF1779 was shown to be active in vivo because it afforded protection against lipopolysaccharide-induced shock in mice, a systemic inflammatory response crucially dependent on tumor necrosis factoralpha production.