Studies on the in vivo-action of leupeptin on the nitrogen retention in rats

A daily s.c. injection of 0.5 mg leupeptin for 7 days does not influence the digestibility of food-N but seems to improve the N-retention. A daily injection of 1.0 mg leupeptin for 14 days is without influence on the digestibility of N, too, but the N-retention was decreased. At this leupeptin level the half-lives of intestinal proteins were prolonged. The data indicate the possibility to influence the N-retention using leupeptin.     

Studies of T-cell activation in chronic inflammation

The strong association between specific alleles encoded within the MHC class II region and the development of rheumatoid arthritis (RA) has provided the best evidence to date that CD4+ T cells play a role in the pathogenesis of this chronic inflammatory disease. However, the unusual phenotype of synovial T cells, including their profound proliferative hyporesponsiveness to TCR ligation, has challenged the notion that T-cell effector responses are driven by cognate cartilage antigens in inflamed synovial joints. The hierarchy of T-cell dysfunction from peripheral blood to inflamed joint suggests that these defects are acquired through prolonged exposure to proinflammatory cytokines such as tumour necrosis factor (TNF)-alpha. Indeed, there are now compelling data to suggest that chronic cytokine activation may contribute substantially to the phenotype and effector function of synovial T cells. Studies reveal that chronic exposure of T cells to TNF uncouples TCR signal transduction pathways by impairing the assembly and stability of the TCR/CD3 complex at the cell surface. Despite this membrane-proximal effect, TNF selectively uncouples downstream signalling pathways, as is shown by the dramatic suppression of calcium signalling responses, while Ras/ERK activation is spared. On the basis of these data, it is proposed that T-cell survival and effector responses are driven by antigen-independent, cytokine-dependent mechanisms, and that therapeutic strategies that seek to restore T-cell homeostasis rather than further depress T-cell function should be explored in the future.     

Increased renal ENaC subunits and sodium retention in rats with chronic heart failure

The goal of this study was to examine acute morphological changes, edema, muscle damage, inflammation, and hypoxia in urethral and vaginal tissues with increasing duration of vaginal distension (VD) in a rat model. Twenty-nine virgin Sprague-Dawley rats underwent VD under anesthesia with the use of a modified Foley catheter inserted into the vagina and filled with saline for 0, 1, 4, or 6 h. Control animals were anesthetized for 4 h without catheter placement. Urogenital organs were harvested after intracardiac perfusion of fixative. Tissues were embedded, sectioned, and stained with Masson's trichrome or hematoxylin and eosin stains. Regions of hypoxia were measured by hypoxyprobe-1 immunohistochemistry. Within 1 h of VD, the urethra became vertically elongated and displaced anteriorly. Edema was most prominent in the external urethral sphincter (EUS) and urethral/vaginal septum within 4 h of VD, while muscle disruption and fragmentation of the EUS occurred after 6 h. Inflammatory damage was characterized by the presence of polymorphonuclear leukocytes in vessels and tissues after 4 h of VD, with the greatest degree of infiltration occurring in the EUS. Hypoxia localized mostly to the vaginal lamina propria, urethral smooth muscle, and EUS within 4 h of VD. Increasing duration of VD caused progressively greater tissue edema, muscle damage, and morphological changes in the urethra and vagina. The EUS underwent the greatest insult, demonstrating its vulnerability to childbirth injury.     

Hypokalemia and sodium retention in patients with diabetes and chronic hepatitis receiving insulin and glycyrrhizin

Of 9 patients with chronic hepatitis treated with intravenous administration of 40 to 200 mg/day of glycyrrhizin, 3 diabetic patients receiving concomitant insulin developed hypokalemia, sodium retention and suppression of both plasma aldosterone concentration and plasma renin activity after the administration for 3 to 6 days. In the remaining 6 patients (5 nondiabetic and 1 diabetic) receiving no insulin, the administration over the long term (18 to 266 days) never caused these abnormalities. The development of hypokalemia and sodium retention in the patients was not associated with increased urinary excretion of potassium, indicating a different condition from pseudoaldosteronism caused by the desoxycorticosterone-like action of glycyrrhizin. These findings suggest that insulin which is known to have hypokalemic, antinatriuretic and antikaliuretic activity, as well as glycyrrhizin plays an important pathogenetic role in the observed electrolyte disturbance, and suppression of both renin and aldosterone.     

Urodynamic findings in chronic retention of urine and their relevance to results of surgery.

Fifty-five consecutive male patients aged 18-77 with chronic retention of urine were investigated urodynamically. All were shown to have obstructed micturition. Inflow cystometry defined two groups, one with high-pressure and one with low-pressure filling. Recent-onset enuresis and upper-tract dilatation as seen on radiography were significantly associated with high-pressure bladder filling. Postoperative studies showed that patients with high-pressure filling on preoperative cystometryhad a better response to outflow-tract surgery. The poor response of the patients with low-pressure filling was due to a high incidence of inadequate detrusor contraction leading to persistent residual urine. Thus urodynamic studies may be used to indicate which patients are likely to benefit from prostatectomy and, after the operation, whether the obstruction has been relieved.     

Studies on the mechanism of selective retention of porphyrins and metalloporphyrins by cancer cells

Comparative studies of the toxicity, stability, and retention of the water-soluble porphyrin, tetraphenylporphyrin sulfonate (TPPS), and its complex with Mn(III), have been made with the human breast cancer cell line MCF-7 wild type, and an adriamycin-resistant line derived from it, termed AdrR. Based on growth inhibition, we determined the maximum non-toxic concentration of MnTPPS tolerated by these cells. The integrity of MnTPPS in vitro was investigated by fluorescence microscopy, and we found that there is very little dissociation of MnTPPS within these cells within 4 days. We report novel proton magnetic resonance relaxation measurements of the bulk water of cells in a gel matrix undergoing perfusion. A slightly greater net uptake of MnTPPS in the wild-type cells was observed compared to AdrR; however, there was no significant difference in retention of MnTPPS. These results indicate that over a period of several hours the mechanism of selective retention of these compounds in tumour cells is not due to specific interaction with heme-binding protein, of which there is enhanced expression in the resistant cells. The fact that the net rate of washout of MnTPPS is approximately the same as the net rate of uptake also appears to eliminate compartmentalization or enzymatic modification of MnTPPS within these cells.     

Studies of lysosomal sialic acid metabolism: retention of sialic acid by Salla disease lysosomes

Purified rat liver lysosomes were incubated in 0.2 M sialic acid resulting in an increase in lysosomal free sialic acid of 3.8 +/- 1.5 nmol/unit beta hexosaminidase. Sialic acid loss by these lysosomes was stimulated 2-3 fold by 25 mM sodium phosphate. Loss of sialic acid by lysosomes from cultured human diploid fibroblasts was similar to that observed in rat liver lysosomes while loss of sialic acid by lysosomes from cultured fibroblasts from a patient with infantile Salla disease occurred much more slowly. Salla disease appears to be the consequence of defective lysosomal transport of sialic acid and is analogous to cystinosis, a disorder of lysosomal amino acid transport.     

Acute exposure and chronic retention of aluminum in three vaccine schedules and effects of genetic and environmental variation

Like the mechanisms of action as adjuvants, the pharmacodynamics of injected forms of aluminum commonly used in vaccines are not well-characterized, particularly with respect to how differences in schedules impact accumulation and how factors such as genetics and environmental influences on detoxification influence clearance. Previous modeling efforts are based on very little empirical data, with the model by Priest based on whole-body clearance rates estimated from a study involving a single human subject. In this analysis, we explore the expected acute exposures and longer-term whole-body accumulation/clearance across three vaccination schedules: the current US Centers for Disease Control and Prevention (CDC) schedule, the current CDC schedule using low aluminum or no aluminum vaccines, and Dr. Paul Thomas’ “Vaccine Friendly Plan” schedule. We then study the effects of an implicit assumption of the Priest model on whether clearance dynamics from successive doses are influenced by the current level of aluminum or modeled by the assumption that a new dose has its own whole-body dynamics “reset” on the day of injection. We model two additional factors: variation (deficiency) in aluminum detoxification, and a factor added to the Priest equation to model the potential impact of aluminum itself on cellular and whole-body detoxification. These explorations are compared to a previously estimated pediatric dose limit (PDL) of whole-body aluminum exposure and provide a new statistic: %alumTox, the (expected) percentage of days (or weeks) an infant is in aluminum toxicity, reflecting chronic toxicity. We show that among three schedules, the CDC schedule results in the highest %alumTox regardless of model assumptions, and the Vaccine Friendly Plan schedule, which avoids >1 ACV per office visit results in the lowest (expected) %alumTox. These results are conservative, as the MSL is derived from data used by FDA to estimate safety of aluminum in adult humans. These results demonstrate high potential utility of modeling variation in patient responses to aluminum. More empirical data from individuals who are suspected of being intolerant of aluminum from vaccines, evidenced by high aluminum retention, neurodevelopmental disorders and/or a myriad of chronic illnesses would help answer questions on whether the model predictions can be used to estimate parameter values tied to genetic factors including genomic sequence variation and family history of chronic illnesses tied to aluminum exposure.     

Studies on the lipid composition in serum and lymphocytes in chronic leukemia]

In 33 patients with chronic lymphatic leukaemia (CLL) the lipids were examined quantitatively and qualitatively in the serum and in the lymphocytes. Besides the 5 main categories of lipids, lysolecithin, sphingomyelin, lecithin and cephalin as well as cholesterol ester subfractions were determined according to their degree of saturation of their fatty acids. Patients suffering from CLL were found to have a moderately raise of serum triglycerides and an increase of cholesterol esters with simple unsaturated fatty acids. Simultaneously the fraction of ester with poly-unsaturated fatty acids is lowered. Leukaemic lymphocytes reveal in general a lowered total lipid content. It mainly consists of phosphatides and free cholesterol. Moreover, the leukaemic lymphocytes contrary to normal ones reveal a lowered content of cholesterol esters, diglycerides and triglycerides.