Hyperkalemia-induced paralysis

Hyperkalemia is an electrolyte abnormality that can lead to severe consequences. Paralysis induced by hyperkalemia has been described in only a few reports. We describe a 60-year-old man who experienced paralysis presumably due to hyperkalemia. He presented to the emergency department with severe weakness in all extremities. The patient's serum potassium concentration was greater than 8 mEq/L and his serum creatinine concentration was 7 mg/dl. Findings on electrocardiography were abnormal. Of note, his drug therapy included lisinopril and naproxen. After treatment for hyperkalemia, the patient's symptoms resolved; however, he was admitted for further workup for renal failure. The patient was discharged after approximately 1 week with a diagnosis of end-stage renal disease. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 5) between the patient's paralysis and hyperkalemia. Although hyperkalemia as a cause of paralysis is extremely rare, clinicians should be aware of this potentially life-threatening, noncardiac toxicity.

Tumor necrosis factor: renaissance as a cancer therapeutic?

Since the discovery of tumor necrosis factor (TNF)-alpha, researchers have pursued many approaches to harness the potency of TNF-alpha and TNF superfamily members to treat human cancers. Several ligands of the TNF superfamily, including TNF-alpha, lymphotoxin, FAS ligand (FasL), and APO2 ligand/TNF-related apoptosis-inducing ligand (Apo2L/TRAIL) have been tested in various stages of clinical research for their anti-tumor efficacy. Moreover, several antibodies to TNF receptor (TNFR) superfamily members are now being explored as cancer therapeutics. Due to the toxicity associated with delivering TNF-alpha systemically at clinically relevant doses, more targeted methods are now seen as a likely alternative to provide a localized therapeutically effective dose of TNF-alpha. In this review we revisit historical attempts to use TNF-alpha to treat human cancer, and put this into the context of more recent targeted strategies to circumvent TNF-alpha's systemic toxicity. We will attempt to integrate the results of pre-clinical and clinical trials with a concise synopsis of the TNF-alpha signaling network, with the goal of reconciling our understanding of how the cell biology and tumor biology mechanistically relate.

Column selectivity in reversed-phase liquid chromatography. VI. Columns with embedded or end-capping polar groups

A previous model of column selectivity for reversed-phase liquid chromatography (RP-LC) has been applied to an additional 21 columns with embedded or end-capping polar groups (EPGs). Embedded-polar-group columns exhibit a significantly different selectivity vs. non-EPG, type-B columns, generally showing preferential retention of hydrogen-bond donors, as well as decreased retention for hydrogen-bond acceptors or ionized bases. EPG-columns are also generally less hydrophobic (more polar) than are non-EPG-columns. Interestingly, columns with polar end-capping tend to more closely resemble non-EPG columns, suggesting that the polar group has less effect on column selectivity when used to end-cap the column versus the case of an embedded polar group. Column selectivity data reported here for EPG-columns can be combined with previously reported values for non-EPG columns to provide a database of 154 different columns. This enables a comparison of any two of these columns in terms of selectivity. However, comparisons that involve EPG columns are more approximate.

Column selectivity in reversed-phase liquid chromatography III. The physico-chemical basis of selectivity

Reversed-phase liquid chromatography (RP-LC) retention data for 23 additional solutes have been acquired to further test and evaluate a general relationship from part I: log alpha = log (k/kref) = eta'H(i) + sigma'S(ii) beta'S(iii) + alpha'B(iv) +kappa'C(v) The physico-chemical origin of terms i-v above is examined here by comparing values of (a) the solute parameters of Eq. (1) (eta', sigma', etc.) vs. solute molecular structure, and (b) the column parameters (H, S, etc.) vs. column properties (ligand length and concentration, pore diameter, end-capping). We conclude that terms i-v correspond, respectively, to hydrophobic (i), steric (ii), hydrogen bonding (iii, iv) and ionic (v) interactions between solute and stationary phase. While steric interaction (term ii) is superficially similar to what previously has been defined as "shape selectivity", the role of the solute and column in determining steric selectivity (term ii) appears more complex than previously proposed for "shape selectivity". Similarly, what has previously been called hydrogen bonding between donor solutes and an acceptor group in the stationary phase (term iv) is very likely an oversimplification.

Column selectivity in reversed-phase liquid chromatography I. A general quantitative relationship

Retention factors k have been measured for 67 neutral, acidic and basic solutes of highly diverse molecular structure (size, shape, polarity, hydrogen bonding, pKa, etc.) on 10 different C18 columns (other conditions constant). These data have been combined with k values from a previous study (86 solutes, five different C8 and C18 columns) to develop a six-term equation for the correlation of retention as a function of solute and column. Values of k can be correlated with an accuracy of +/- 1-2% (1 standard deviation). This suggests that all significant contributions to column selectivity have been identified (and can be measured) for individual alkyl-silica columns which do not have an embedded polar group. That is, columns of the latter kind can be quantitatively characterized in terms of selectivity for use in the separation of any sample.

Column selectivity in reversed-phase liquid chromatography II. Effect of a change in conditions

The isocratic retention of 67 widely-different solutes in reversed-phase liquid chromatography (RP-LC) has been investigated as a function of temperature and mobile phase composition (% B) for three different C18 columns. Similar studies were also carried out in a gradient mode, where temperature, gradient time and solvent type were varied. These results show that changes in retention with these conditions are similar for each of these three columns. This suggests that relative column selectivity as defined by experiments for one set of experimental conditions will be approximately applicable for other conditions, with the exception of changes in mobile phase pH-which can affect values of the column parameter C (a measure of silanol ionization). Column selectivity as a function of pH was explored for several columns.

Variability of column selectivity for reversed-phase high-performance liquid chromatography compensation by adjustment of separation conditions

Reversed-phase columns are widely used in assays based on high-performance liquid chromatography (HPLC). When such assays are repeated over time, it is often necessary to replace the column. In such cases, the selectivity of columns from different production batches may prove sufficiently variable to result in a failed separation. It is possible to compensate for differences in column selectivity by making small changes (adjustments) in separation conditions. The present paper describes an efficient procedure for choosing adjusted conditions and discusses its general applicability.

Natural infection of duck embryos with duck hepatitis B virus: time and tissue sequence of infection

There have been no studies addressing the detailed sequence of embryonic infection with duck hepatitis B virus (DHBV). Therefore, duck embryos from flocks infected with DHBV were examined to study the sequence of infection by DHBV in various embryonic tissues. Embryos from flocks infected with DHBV were harvested in duplicates from 7 to 25 days of incubation. Whole embryos (to 12 days) or dissected embryonic tissues were fixed, paraffin embedded, and stained for DHBV surface antigen (DHBsAg) using a peroxidase-antiperoxidase technique. Isolated hepatic cells were infected in 7-day-old embryos, and these increased in number until 11 days, when most cells were positive for DHBsAg. Endocrine pancreatic cells were positive from day 10, but only an occasional exocrine pancreatic cell was infected after day 20. Renal tubule cells were positive for DHBV by day 11, increasing in number until about day 18, after which a decline in numbers of infected cells occurred. Renal glomeruli became positive for DHBsAg from day 24. When present in the developing embryo, thymus, bursa of Fabricius, spleen, bone marrow, lung, and duodenum remained negative for DHBsAg. It was concluded that the timing of infection of specific tissues was not necessarily related to cellular maturity but may reflect a need for specific metabolic functions that permit viral replication.