Abuse of phencyclidine (PCP) a laboratory experience

Emergency Room patients at Riverside General Hospital who are found by the attending physician to have depressed sensorium and altered personality are routinely subjected to urine tests for various drugs of abuse including phencyclidine (PCP). The findings of the laboratory analysis of these patients are presented in this paper. The toxicology laboratory of this hospital performs screening procedures for various drugs on urine specimens by thin layer chromatography. Drugs detected are confirmed by gas chromatography and a homogeneous enzyme immunoassay technique. In 1981, 1.6% of the urine specimens of patients in the above-mentioned category were found to be positive for PCP. This percentage increased sharply during 1982 (5.8%) and 1983 (5.6%). During 1984 and 1985 the percentage dropped to 4.2% and 4.6%. It is implied from data that the abuse of this drug in this area has leveled off. The data also indicated that PCP is predominantly used by young adults with ages ranging from 21 to 30 years. The abuse of this drug in people over 40 years of age is comparatively very small. Among users of this drug, 67.5% are men and 32.5% are women. Out of 68 women found to be abusing PCP, 5 delivered their babies in this hospital. PCP was detected in the urine specimens of each of these babies. Four out of the five infants showed withdrawal symptoms such as extreme irritability, jitteriness, hyperactivity with high pitched cries and a poor ability to take food.     

Kidney transplantation in patients travelling from the UK to India or Pakistan

Sir, I read with great interest the letter by Higgins and co-workers[1].     

Intravenous captopril in congestive heart failure

Hemodynamic and neurohumoral effects of intravenous captopril were studied in ten patients with severe chronic congestive heart failure (NYHA Functional Class III and IV). Incremental bolus doses of captopril, titrated to a maximum cumulative dose of 15 mg, were given at 10-minute intervals. Systemic arterial pressure, mean pulmonary capillary wedge pressure, systemic vascular resistance, mean pulmonary artery pressure, and heart rate decreased (P less than .05). Cardiac index and stroke volume index increased (P less than .05). Maximum hemodynamic effects occurred after cumulative doses of 7 mg and were seen within 30 minutes after initiation of therapy; responses persisted for 30-90 minutes after the last dose. Plasma renin activity increased, and plasma atrial natriuretic factor concentration decreased. No adverse effects were observed with the use of intravenous captopril. Thus, intravenous captopril produces rapid and favorable hemodynamic improvement in advanced heart failure patients.     

Damage and mutagenesis of bacteriophage lambda induced by high pH.

Bacteriophage lambda-Escherichia coli complexes exhibited remarkable sensitivity to alkaline pH 10.0 at 37 degrees C. The decline in plaque forming units after alkali treatment was more pronounced in complexes with some of the radiation repair defective mutants of E. coli K-12, i.e. uvrArecA, recA, rer and lexA mutants as compared to those of uvrA, recB and wild-type strains. The red gene of lambda phage and recA gene of E. coli seem to have a complementary effect on the alkali induced lesions. Alkaline treatment to lysogenic lambda phage was also found to be mutagenic. An enhanced level of mutagenesis was observed when treated phage particles were allowed to adsorb on treated wild-type bacteria. Moreover, the alkali treatment to lysogen (lambda cI857-E. coli) resulted in prophage induction in nutrient broth even at 32 degrees C. Thus on the basis of these results the role of error prone SOS repair systems in the repair of alkali induced lesions in lysogenic bacteriophage lambda has been suggested.     

Role of protein kinase C in the modulation of multidrug resistance: expression of the atypical gamma isoform of protein kinase C does not confer increased resistance to doxorubicin.

Cross-resistance to anticancer drugs, termed multidrug resistance (MDR), is functionally associated with the expression of a plasma membrane, energy-dependent, drug efflux pump termed P-glycoprotein (PGP), the product of the mdr1 gene. We have shown previously that MCF-7 breast carcinoma cells transfected with the human mdr1 gene (BC-19 cells) exhibit greater MDR when stably transfected with protein kinase C alpha (PKC alpha). We now demonstrate that transfection of BC-19 cells with the gamma isoform of PKC (BC-19/PKC gamma cells), which is not normally present in BC-19 cells, does not confer increased resistance to doxorubicin, despite a 19-fold increase in PKC activity. All of the increased PKC activity is accounted for by PKC gamma and it is rapidly down-regulated by phorbol dibutyrate, within 15 min of treatment. Endogenous PKC alpha and PKC epsilon activities are not affected by phorbol dibutyrate. The cytotoxicity of doxorubicin was similar in BC-19/neo or BC-19/PKC gamma cells after either 2-hr or continuous drug exposure, and co-treatment with phorbol dibutyrate increased resistance to doxorubicin 4-fold in both cell lines. Phosphorylation of PGP was similar in both cell lines and drug accumulation was not affected by overexpression of PKC gamma. These results demonstrate that transfection of PGP-expressing cells with an atypical isoform of PKC does not confer increased MDR, and they suggest that the regulation of PGP is phenotype specific with respect to the isoform of PKC.     

The assembly of the factor X-activating complex on activated human platelets

Summary.  Platelet membranes provide procoagulant surfaces for the assembly and expression of the factor X-activating complex and promote the proteolytic activation and assembly of the prothrombinase complex resulting in normal hemostasis. Recent studies from our laboratory and others indicate that platelets possess specific, high-affinity, saturable, receptors for factors XI, XIa, IX, IXa, X, VIII, VIIIa, V, Va and Xa, prothrombin, and thrombin. Studies described in this review support the hypothesis that the factor X-activating complex on the platelet surface consists of three receptors (for the enzyme, factor IXa; the substrate, factor X; and the cofactor, factor VIIIa), the colocalization of which results in a 24 million-fold acceleration of the rate of factor X activation. Whether the procoagulant surface of platelets is defined exclusively by procoagulant phospholipids, or whether specific protein receptors exist for the coagulant factors and proteases, is currently unresolved. The interaction between coagulation proteins and platelets is critical to the maintenance of normal hemostasis and is pathogenetically important in human disease.     

Activities of flavonoids for the cleavage of DNA in the presence of Cu(II): correlation with generation of active oxygen species.

The activities of several flavonoids and the related nonflavonoid compound epicatechin were compared with respect to Cu(II)-induced strand scission of DNA by using two different assays. The same series of compounds was used to study the stoichiometry of Cu(II) reduction in the absence of DNA. The compounds were compared for their ability to generate superoxide, hydrogen peroxide and the Cu(II)-dependent production of hydroxyl radicals. Flavonoids were examined to assess the production of a charge-transfer complex with Cu and the rate of decay of the complexes were compared. All the compounds tested had some ability to cause DNA strand scission in the presence of Cu(II), with myricetin being the most active and galangin the least active. The ability to cause such scission correlated with the rate of decay of the charge-transfer complex, the ability to generate active oxygen species and with the stoichiometry of Cu(II) binding. Analysis of the data in the light of the structural differences between the flavonoids led to a discussion of alternative Cu(II)-sequestering mechanisms.     

A practical profile of integrated safety assessment of near-surface disposal of radwaste at PINSTECH.

Near-surface or shallow land disposal of radioactive waste has been the primary practice at the Pakistan Institute of Nuclear Science and Technology (PINSTECH). The adopted choice of this mode of disposal has been based on a study of the site and the quality and quantity of waste generated at the 5 MW reactor with HEU fuel. Specific measures regarding the radiation safety of the workers and environmental protection have been adopted. The waste disposal operations are conducted to meet local regulatory requirements, IAEA recommendations and internationally endorsed principles such as ALARA (as low as reasonably achievable - economic, social and other relevant factors being considered). The data obtained through the years of operational and management experience have manifested the robustness of the disposal system and reliability of the disposal criterion, and have also served to further refine the latter. Consequently, confidence in the current shallow-land-burial practices has increased. Radiological safety of these practices has been assessed by addressing different aspects of the safety and disposal system. These parameters, as indices of a non-exclusive and operational safety model, are presented.