High level expression and purification of peptide methionine sulfoxide reductase in Escherichia coli

The enzyme peptide methionine sulfoxide reductase catalyzes the conversion of methionine sulfoxide residues in proteins to methionine. The 636 nucleotide coding region of the peptide methionine sulfoxide reductase gene has been amplified from a genomic clone using the polymerase chain reaction and the product was subcloned into plasmid pGEX-2T downstream of the glutathione S-transferase gene under control of the tac promoter. Escherichia coli XL1-Blue cells transformed with this plasmid and induced with isopropylthio-beta-galactoside expressed high levels of the fusion protein. The protein was soluble and was purified to homogeneity by affinity binding to a glutathione-agarose resin followed by cleavage of the fusion protein with thrombin. Both the fusion protein and the purified peptide methionine sulfoxide reductase protein showed high peptide methionine sulfoxide reductase activity.

Raising plasma phosphorus levels by phosphorus-enriched, bicarbonate-containing dialysate in hemodialysis patients

In 6 hemodialysis patients, enriching the "base concentrate" of a bicarbonate-containing dialysate-generating system with phosphorus succeeded in raising plasma phosphorus levels.

A comparison of expiration dating period estimation methods

Two methods of estimating expiration date have been compared. For a drug whose potency is expected to decrease with time, method 1 fits a linear regression line to the stability data, calculates a 95% lower confidence limit of the true degradation line, and estimates the expiration date by comparing the confidence limit with the lower specification limit. Method 2 calculates a 95% lower confidence limit b1 of the slope of the true degradation line, constructs a new line y" using b1 as its slope, and finally estimates the expiration date by comparing y" with the lower specification limit. In this work we show that in most practical situations, method 1 estimates greater expiration date than method 2.

Potent substituted-3 beta-phenyltropane analogs of cocaine have cocaine-like discriminative stimulus effects

Two novel phenyltropane analogs of cocaine, 3 beta-(4-chlorophenyl) tropane-2 beta-carboxylic acid methyl ester (RTI-COC-31) and 3 beta-(4-methylphenyl) tropane-2 beta-carboxylic acid methyl ester (RTI-COC-32), were evaluated for cocaine-like discriminative stimulus effects in rats. Two groups of rats were trained to discriminate 10 mg/kg cocaine from saline using a standard 2-lever discrimination procedure with correct-lever responding reinforced under a fixed-ratio 20 schedule of food reinforcement. One group of rats was used to evaluate RTI-COC-31 and the unsubstituted-3 beta-phenyltropane reference compound WIN 35,065-2 in substitution tests. Another group of rats was used to evaluate RTI-COC-32. For purposes of comparison, a cocaine dose-effect curve was also determined in each group. Both RTI-COC-31 and RTI-COC-32, as well as WIN 35,065-2, substituted completely for cocaine. RTI-COC-31 was 26.8-fold and RTI-COC-32 was 6-fold more potent than cocaine for producing cocaine-lever responding. The potent cocaine-like effects of the RTI analogs in vivo correspond with their high affinities for a cocaine recognition site on the dopamine transporter, providing further evidence that this site may mediate behavioral effects of cocaine relevant to its abuse.

Changes in AIDS case reporting after hospital site visits

In an effort to improve AIDS case reporting, site visits (meetings with hospital staff to encourage reporting) were made to all Philadelphia hospitals. Comparisons of hospitals visited during a 7-week period with hospitals not visited during that period indicated that the site visits were followed by a marked increase in case reports. No similar increase was observed at the comparison hospitals. The increased reporting was accompanied by an increased lag time from diagnosis to report, suggesting that the additional reports at visited hospitals were the result of the identification of previously missed cases rather than a speedup of reporting. Cases reported after the visits were more likely to have white-collar occupations or private medical insurance than were those reported before the visits.

Synthesis, ligand binding, QSAR, and CoMFA study of 3 beta-(p-substituted phenyl)tropane-2 beta-carboxylic acid methyl esters

A series of 3 beta-(p-substituted phenyl)tropane-2 beta-carboxylic acid methyl esters (2) were synthesized and found to possess high affinity for the cocaine binding site in rat striatum. The p-chloro (2c) and p-iodo (2n) compounds, which were the most potent analogues prepared, were found to be 85 and 78 times more potent than (-)-cocaine. The p-bromo (2m) and p-methyl (2d) were also 56 and 60 times more potent than cocaine. QSAR and CoMFA studies were conducted to correlate binding affinity of the cocaine analogues with their structural features. Whereas the QSAR study gave relatively low correlations, the CoMFA study gave a correlation with high predictive value.

Haemodynamic responses to nonhypotensive central hypovolaemia induced by lower body negative pressure in men and women

Haemodynamic responses to low levels of lower body negative pressure (LBNP) were investigated in two groups of healthy, normotensive volunteers (8 men and 8 women) during two repeated experimental runs on two occasions, the latter determined by the different phases of the menstrual cycle in the women. The data consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP), pulse rate (fc), forearm blood flow (FBF) and forearm vascular conductance (FC). The resting cardiovascular status was similar in men and women, except that women had a significantly higher fc than men. LBNP (1.3, 2.7 and 4 kPa) had no significant effect on any BP variable or on fc. However, FBF and FC were reduced at all levels of LBNP. Significant overshoots in FBF and FC were seen in all subjects following the release of LBNP of 2.7 and 4 kPa and, in most cases, after release of LBNP of 1.3 kPa. There were no significant gender differences in any of the responses to LBNP. Furthermore, none of the cardiovascular variables measured showed significant differences between the follicular and luteal phases of the menstrual cycle in women, either at rest or during exposure to LBNP, and the responses in the men on the two occasions were not different. These findings indicate that gender differences in responses to LBNP hypothesized previously are not apparent during and after exposure to low levels of LBNP.

Reactivation of Epstein-Barr virus during early infection with human immunodeficiency virus

Reactivation of Epstein-Barr virus (EBV) in early human immunodeficiency virus (HIV) infection was investigated in 49 homosexual men who seroconverted to HIV (cases) as compared with 49 matched controls who remained seronegative to HIV during a longitudinal study. EBV infection was reactivated in cases 6 months, but not 12 months, prior to HIV seroconversion as compared with controls and remained reactivated during 18 months of follow-up after HIV seroconversion, as shown by increases in immunoglobulin (Ig) G antibody titers to EBV early antigen. Antibody titers to EBV viral capsid antigen did not differ between cases and controls prior to the time of seroconversion to HIV but were significantly increased among cases by the first seropositive study visit and remained elevated during the 18 months after HIV seroconversion. Total serum IgG levels were increased in cases at the visit of seroconversion, and during 18 months of follow-up, but did not correlate with enhanced IgG production specific for EBV antigens. Significant decreases in numbers of CD4+ cells and increases in numbers of CD8+ cells during this early phase of HIV infection were not associated with changes in patterns of EBV antibody responses. Reactivation of EBV beginning 6 months before HIV seroconversion may have implications regarding the role of this herpesvirus in the pathogenesis of HIV.

Effects of dietary fish oil on the induction of experimental membranous nephropathy in the rat

We examined the effect of a fish oil-enriched diet on the development of experimental membranous nephropathy in the rat induced by administration of cationic bovine gamma globulin (CBGG). Rats were placed on a fish oil-enriched diet and control rats received a diet containing an equivalent amount of beef tallow. After 6 weeks on either diet, rats were pre-immunized and injected with CBGG. Proteinuria was significantly reduced in the fish oil-fed group as compared to the control group (160 +/- 40 mg/24 hours, n = 15, versus 280 +/- 36 mg/24 hours, n = 17, p less than 0.02). Glomerular filtration rate was also significantly higher in the fish oil-fed rats than in controls (0.91 +/- 0.07 ml/minute, n = 11, versus 0.60 +/- 0.05 ml/minute, n = 10, p less than 0.005). Glomerular production of prostaglandin E2 and thromboxane B2 the stable product of thromboxane A2, were inhibited by 68% and 70%, respectively, by the fish oil-enriched diet (n = 8, p less than 0.01 versus control). Glomerular leukotriene B4 was also inhibited by 50% in the fish oil-treated rats (n = 6, p less than 0.01), but inhibition of leukotriene B4 by the specific inhibitor L-663,536 in control rats did not ameliorate proteinuria. There was no difference in the amount of distribution of glomerular immune deposits as demonstrated by immunofluorescence and electron microscopy between the experimental and control groups. Moreover, comparable amounts of glomerular IgG deposits were present in the two groups. The specific immune response, assessed by measuring anti-BGG antibody levels, was not different between the two dietary groups, while more than 85% suppression of the splenic T- and B-cell mitogenic response to concanavalin-A and lipopolysaccharide was noted in rats fed the fish oil-enriched diet. We conclude that a fish oil-enriched diet reduces proteinuria and preserves the glomerular filtration rate in rats with CBGG-induced membranous nephropathy. Its mechanism of action remains to be established.

Isothiocyanate derivatives of cocaine: irreversible inhibition of ligand binding at the dopamine transporter

Isothiocyanate derivatives of (-)-cocaine were prepared and tested for inhibitory potency at the cocaine receptor in rat striatal membranes. Coincubation with m-isothiocyanatobenzoylecgonine methyl ester (m-ISOCOC), p-isothiocyanatobenzoylecgonine methyl ester (p-ISOCOC), and 3 beta-(4-isothiocyanatophenyl)tropane-2-carboxylic acid methyl ester (ISOWIN) resulted in inhibition of [3H]WIN 35,428 binding, but the compounds were about 10-fold weaker than (-)-cocaine. However, p-ISOCOC was approximately 3-fold more potent than metaphit, an isothiocyanate derivative of phencyclidine. p-ISOCOC was equipotent at the serotonin transporter but was much less potent at the norepinephrine transporter and was inactive at the D2 dopamine receptor at 1000 microM concentration. The IC50 value for m-ISOCOC and p-ISOCOC varied with tissue concentration, suggesting irreversible inhibition of binding. Preincubation with m-ISOCOC and p-ISOCOC resulted in inhibition of [3H]WIN 35,428 binding that could not be removed by washing of the membranes; in contrast, preincubation with (-)-cocaine caused inhibition that was readily removed by washing. Preincubation with 1 microM concentrations of p-ISOCOC resulted in a large reduction in Bmax of the high affinity binding site for [3H]WIN 35,428. Preincubation with 100 microM p-ISOCOC eliminated the high affinity site and apparently reduced the affinity at the low affinity site. Coincubation of 10 microM p-ISOCOC with 100 microM cocaine prevented the total loss of [3H]WIN 35,428 binding. The uptake of [3H]dopamine was inhibited by p-ISOCOC with an IC50 comparable to that of cocaine. Additionally, preincubation of rat striatal synaptosomes with 10 microM p-ISOCOC reduced the Vmax of [3H]dopamine uptake after washing. These data suggest that m-ISOCOC and p-ISOCOC are useful irreversible acylators of (-)-cocaine binding sites at the dopamine transporter.

Antibacterial activity and inhibition of protein synthesis in Escherichia coli by antisense DNA analogs

Protein synthesis, which takes place within ribosomes, is essential for the survival of any living organism. Ribosomes are composed of both proteins and RNA. Specific interaction between the 3' end CCUCC sequence of prokaryotic 16S rRNA and a partially complementary sequence preceding the initiating codon of mRNA is believed to be a prerequisite for initiation of protein synthesis. Here we report the use of short (three to six nucleotides) synthetic DNA analogs complementary to this sequence to block protein synthesis in vitro and in vivo in Escherichia coli. In the DNA analogs the normal phosphodiester bond in the antisense DNA was replaced by methylcarbamate internucleoside linkages to enhance transport across plasma membranes. Of the analogs tested, those with the sequence AGG and GGA inhibit protein synthesis and colony formation by E. coli strains lacking an outer cell wall. Polyethylene glycol 1000 (PEG 1000) was attached to the 5' end of some of the test methylcarbamate DNAs to enhance solubility. Analogs of AGG and GGAG with PEG 1000 attached inhibited colony formation in normal E. coli. These analogs may be useful food additives to control bacterial spoilage and biomedically as antibiotics.

Cardiovascular reflex responses in Bangladeshi and European subjects

1. Cardiovascular responses to three different interventions, namely the Valsalva manoeuvre, deep breathing and a cold stimulus on the face, were studied in two ethnic groups (European and Bangladeshi) that have been shown to differ in the prevalence of hypertensive-vascular disease. The data obtained consisted of systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate measured by using a beat-by-beat non-invasive blood pressure monitor (the Finapres), forearm blood flow determined by venous occlusion plethysmography, and calculated forearm vascular resistance. 2. The resting haemodynamic status was similar in European and Bangladeshi subjects. However, Bangladeshi subjects showed a greater increase in heart rate, but only after 20 s into the Valsalva manoeuvre, and greater overshoots in mean blood pressure after the manoeuvre than the European subjects. Furthermore, after cold face stimulation the fall in forearm vascular resistance to baseline levels was delayed in Bangladeshi subjects relative to that in the European subjects. 3. There were no inter-group differences in the reflex bradycardia relative to mean blood pressure or in the cardiac baroreflex sensitivity estimated from systolic blood pressure and pulse interval after the Valsalva manoeuvre. In addition, values for the mean difference between maximum and minimum pulse intervals during deep breathing did not differ in Bangladeshi and European subjects. 4. These findings together suggest that, although cardiac vagal reflex responses appear similar in the two groups, sympatho-adrenal influences on the heart and vasculature may be greater in Bangladeshi subjects than in European subjects.

Studies on glycosylated plasma proteins in diabetic patients

The level of glycosylated haemoglobin in the blood is considered as an index of long term blood glucose levels in diabetic patients. Glycosylation of structural proteins also occur. The present study describes the levels of glycosylated blood proteins (nonenzymatic) and blood glycoproteins (enzymatic glycosylation) in four groups of diabetic patients (n = 80) as well as non-diabetic control subjects (n = 20). The patients were divided according to the treatment they received. Glycosylated haemoglobin, glycosylated plasma proteins, fasting plasma glucose, hexosamine, sialic acid and mucoproteins were measured in each subject. All of these measurements were significantly increased in diabetic patients however, glycoproteins were not significantly correlated with glycosylated haemoglobin or fasting glucose.

Effects of hypertonic peritoneal dialysis solutions on neutrophil superoxide production

Superoxide produced by neutrophils plays an important role in the killing of bacterial pathogens. The effects of glucose-containing peritoneal dialysis solutions on superoxide production by canine and human neutrophils were studied. A significant decrement in superoxide generation was noted with the 2.27% and 3.86% glucose solutions. The results suggest that hypertonic peritoneal dialysis solutions curtail neutrophil superoxide generation.

Nuclease S1 mapping of 16S ribosomal RNA in ribosomes

Escherichia coli 16S rRNA and 16S-like rRNAs from other species have several universally conserved sequences which are believed to be single-stranded in ribosomes. The quantitative disposition of these sequences within ribosomes is not known. Here we describe experiments designed to explore the availability of universal 16S rRNA sequences for hybridization with DNA probes in 30S particles and 70S ribosomes. Unlike previous investigations, quantitative data on the accessibility of DNA probes to the conserved portions of 16S rRNA within ribosomes was acquired. Uniquely, the experimental design also permitted investigation of cooperative interactions involving portions of conserved 16S rRNA. The basic strategy employed ribosomes, 30S subunits, and 16S rRNAs, which were quantitatively analyzed for hybridization efficiency with synthetic DNA in combination with nuclease S1. In deproteinated E. coli 16S rRNA and 30S subunits, the regions 520-530, 1396-1404, 1493-1504, and 1533-1542 are all single-stranded and unrestricted for hybridization to short synthetic DNAs. However, the quantitative disposition of the sequences in 70S ribosomes varies with each position. In 30S subunits there appear to be no cooperative interactions between the 16S rRNA universal sequences investigated.

New, potent cocaine analogs: ligand binding and transport studies in rat striatum

Two potent cocaine analogs have been developed that have the highest known affinities for the cocaine binding site in rat striatum. Both 3 beta-(4-chlorophenyl)- (RTI-COC-31) and 3 beta-(4-methylphenyl)-tropane-2-carboxylic acid methyl ester (RTI-COC-32) compete for [3H]WIN 35,428 and [3H]mazindol binding with a IC50 that is 100 times more potent than that of (-) cocaine. Additionally, these compounds inhibit [3H]dopamine uptake with a similar, high potency. These results may lead to the development of high affinity probes for the cocaine binding site.

Superoxide generation by neutrophils after exposure to a conventional peritoneal dialysis solution for different time periods

Neutrophils were isolated from canine blood and exposed to a conventional, acidic, lactate-containing peritoneal dialysis solution for 0, 2 and 4 minutes in one study and 0, 4, 7 and 10 minutes in another. Superoxide generation, expressed in nanomoles per million cells, was determined using a method based on the superoxide dismutase-inhibitable reduction of ferricytochrome c. Brief exposure of neutrophils to a conventional dialysis solution could significantly inhibit the generation of superoxide by neutrophils.

Changes in glycosylated proteins in long-term complications of diabetes mellitus

Increased glycosylation of various proteins in diabetic patients has been reported by many authors. In the present study, the extent of non-enzymatic glycosylation in diabetic patients with or without chronic complications was investigated. Eighty-five diabetic patients were studied, 20 were without any clinical evidence of chronic complications while the remainder were suffering from cataract (n = 18), retinopathy (n = 16), peripheral neuropathy (n = 16) and cardiovascular complications like angina pectoris, myocardial infarction and hypertension (n = 15). All patients were selected on clinical grounds. Fifteen apparently healthy subjects of similar age and weight were studied as control subjects. Fasting plasma glucose was increased in all diabetic patients and correlated significantly with glycosylated hemoglobin, glycosylated plasma protein and serum fructosamine concentrations. There was no significant difference between diabetic patients with or without chronic complications in the levels of fasting plasma glucose, glycosylated plasma proteins, glycosylated hemoglobin, serum fructosamine, mucoprotein, hexosamine, sialic acid and fucose. Alpha-2 globulin fraction was increased in both uncomplicated and complicated diabetic patients and albumin was found to be decreased in patients with cataract, peripheral neuropathy and cardiovascular diseases. Alpha-1 and beta globulins were significantly decreased in patients with cardiovascular diseases and retinopathy respectively while gamma globulin was increased in retinopathy patients. In uncomplicated diabetic patients alpha-1 glycoprotein was decreased and gamma glycoprotein was increased. In diabetic patients with retinopathy, alpha-1 glycoprotein was elevated significantly while beta glycoprotein was decreased.

Lung function in teenage Bangladeshi boys and girls

Data on forced vital capacity, forced expiratory volume in one second and peak expiratory flow rate were obtained in a group of 588 healthy and well-nourished (but not obese) Bangladeshi teenagers to establish normal values in this population. Bangladeshi girls in their early teens showed higher peak expiratory flow rates than boys of the same age but while this continued to rise in boys after the age of 15 years the peak expiratory flow rate in girls seemed to have attained its maximum values by that age. Correlations between sitting height and the lung function variables were found to be marginally greater than those with standing height. Prediction equations were calculated for each lung function variable with sitting and standing separately. Comparison of the results in our study with those reported from other ethnic groups indicate that Bangladeshi values are lower than those of Europeans, Jordanians or Chinese but not significantly different from those reported for Libyans. Since in practice, genetic, nutritional and environmental factors are not readily disentangled, norms for a given study population need to be derived from healthy subjects of similar background and ethnicity.

The effects of propranolol or atenolol on the cardiovascular responses to central hypovolaemia in Europeans and Bengalees

1. The effects of single oral doses of propranolol (80 mg), or atenolol (100 mg) on resting heart rate, blood pressure, forearm blood flow and forearm vascular resistance and on responses to central hypovolaemia, were compared with those of placebo in nine healthy European and nine healthy Bengalee volunteers, in a double-blind, three-period, cross-over study. 2. Atenolol induced a significant reduction in resting systolic blood pressure (SBP) in Europeans but not in Bengalees, although the bradycardic effects of atenolol were similar in both groups. Atenolol did not have any significant effect on forearm blood flow (FBF) or forearm vascular resistance (FVR) in either group. In the presence of propranolol (80 mg) there were no statistically significant falls in BP but there were significant bradycardias, falls in FBF and rises in FVR that were similar in Europeans and Bengalees. 3. In the presence of placebo Europeans exhibited significant falls in diastolic blood pressure (DBP) during lower body negative pressure (LBNP) of 20 and 30 mm Hg. Bengalees did not show falls in DBP during LBNP. However, there were no significant differences between DBP responses in Europeans and Bengalee subjects. Both Bengalees and European subjects showed similar reductions in FBF and FVR during LBNP of 30 mm Hg. 4. In the presence of propranolol, significant changes in forearm blood flow and forearm vascular resistance were evident in Bengalee subjects during LBNP of 20 mm Hg and 30 mm Hg, whereas in the Europeans significant changes in those variables did not occur at any level. The changes in FBF and FVR during LBNP of 20 and 30 mm Hg in Bengalee and European subjects were significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate tolerance status in patients with myocardial infarction

Hyperglycemia is an important independent risk factor in the development of coronary artery disease. Sixty one patients suffering from chronic and acute myocardial infarction out of which 12 patients were diabetic and 10 normal control subjects were investigated. The patients without diabetes and control subjects were subjected to oral and intravenous glucose tolerance tests. It was observed that the post load glucose level of most of the patients and fasting insulin level of patients without diabetes were higher as compared with control subjects. From the intravenous glucose tolerance test, half life of glucose and glucose assimilation coefficient were determined. Half life of glucose was increased significantly and glucose assimilation coefficient was decreased in the patients with myocardial infarction as compared with those of control subjects. The observations confirm that carbohydrate intolerance in myocardial infarction is not due to suppression of insulin secretion but due to peripheral utilization.

Multiple tuberculous bone lesions simulating metastatic disease

A case history is presented for a patient who developed multiple bone lesions, mainly in ribs and spine. The lesions were suspected to be due to disseminated carcinoma but the diagnosis of tuberculosis was proven by biopsy and culture.

Effects of bicarbonate-containing versus lactate-containing peritoneal dialysis solutions on superoxide production by human neutrophils

Human neutrophils were isolated from healthy volunteers and exposed to either bicarbonate-containing (pH 7.4) or lactate-containing (pH 5.2) peritoneal dialysis solution in vitro. Superoxide production by neutrophils was measured by a method based on the superoxide dismutase-inhibitable reduction of ferricytochrome c. Bicarbonate-containing peritoneal dialysis solution was found to be superior to the lactate-containing one in facilitating the production of superoxide anion by human neutrophils.

Contrast media-induced lipid peroxidation in the rat kidney

Lipid peroxidation of biological membranes is often implicated in tissue injury. The authors compared the effects of ionic and nonionic contrast media (CM) on the induction of lipid peroxidation in rat kidney and its impact on renal function. Male Wistar rats weighing 200 to 230 grams were dehydrated for 24 hours and divided into 6 groups (n = 15/group). On day 0, groups 1 through 3 were injected with 25% glycerol (10 mL/kg, im) and rats from groups 4 through 6 received an equivalent amount of intramuscular saline. The next day, rats from groups 1 and 4 were injected with normal saline (10 mL/kg, iv); groups 2 and 5 received the ionic CM, diatrizoate, and groups 3 and 6 received the nonionic CM, iopromide. Each CM was tested at 10 mL/kg BW. At 24-hour intervals, 5 rats from each group were sacrificed. In rats injected with CM (diatrizoate or iopromide) alone, no changes in serum creatinine or kidney structure were demonstrated. In glycerol treated rats, a peak in serum creatinine was seen on day 2 which returned to normal level by day 4. Histologic changes included focal tubular damage and intraluminal debris. Malondialdehyde (MDA), a marker of lipid peroxidation concentration was higher than in controls (P less than 0.05). In diatrizoate-injected rats, increase in serum creatinine on day 4 was ten times higher than glycerol; severe morphological alterations in proximal tubules were noted and significant increases in renal MDA concentration were obtained (P less than .05). Iopromide (on day 4), caused a five-fold increase in serum creatinine compared with glycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhanced antibody responses to Epstein-Barr virus in HIV-infected homosexual men

We investigated the association between human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV) infections in 593 homosexual men. The status of EBV infection in this group was evaluated based on serological evidence of EBV-specific antibody responses. The geometric mean titers (GMT) of antibody to EBV capsid antigen (EBV-VCA) (1:154) and EBV early antigen (EA) (1:16) in 141 HIV-seropositive men were significantly higher than respective titers in 452 HIV seronegative men (1:95 and 1:12). Antibody titers to EBV were higher in HIV-infected men with lymphadenopathy than in asymptomatic HIV-seropositive men. However, these correlation were less evident in patients with AIDS-related complex. Elevated antibody titers to EBV were found to be independent of levels of total serum IgG. Cytomegalovirus (CMV) antibody titers were also found to be significantly increased among HIV-seropositive men, independent of total IgG. Antibody titers to EBV were not correlated with those to CMV in either HIV-seronegative or HIV-seropositive men. Subjects without evidence of HIV infection, but who had high antibody titers to EBV-VCA and EBV-EA, had elevated mean numbers of CD3+, CD4+, and CD8+ cells, and lower levels of CD4+/CD8+ cell ratios compared to subjects with low EBV-antibody titers. This study suggests that the elevated levels of circulating antibodies against EBV in homosexual men are associated with loss of control of latent EBV due to HIV infection.

Role of prostaglandins and thromboxane in the control of renal hemodynamics in experimental liver cirrhosis

Although there is considerable evidence that vasodilator prostaglandins such as prostaglandin E2 (PGE2) modulate renal hemodynamics in liver cirrhosis, the role of the vasoconstrictor thromboxane A2 (TXA2) is controversial. We measured renal hemodynamics and glomerular eicosanoid production in cirrhotic and control rats. Renal plasma flow, as estimated by para-aminohippurate clearance (CPAH) and glomerular filtration rate, as determined by inulin clearance (CIN), were comparable between groups; glomerular production of PGE2 and TXA2 (estimated by the metabolite thromboxane B2 [TXB2]) was slightly but not significantly higher in cirrhotic than in control rats (PGE2: 1060 +/- 142 pg/mg glomerular protein vs 854 +/- 288 pg/mg glomerular protein; TXB2: 782 +/- 103 pg/mg glomerular protein vs 468 +/- 104 pg/mg glomerular protein). Addition of serum from cirrhotic rats to the incubation media failed to increase eicosanoid production in glomeruli obtained from either cirrhotic or control rats. Cyclooxygenase inhibition with 5 mg/kg indomethacin, a dose sufficient to result in a 68% inhibition of glomerular PGE2 synthesis, decreased both CPAH (from 6.59 +/- 0.69 ml/min to 4.52 +/- 0.67 ml/min, p less than 0.05) and CIN (from 1.34 +/- 0.16 ml/min to 0.68 +/- 0.07 ml/min, p less than 0.01) in cirrhotic rats. Thromboxane synthesis inhibition with 1 mg/kg UK-38485, which resulted in an 84% decrease in glomerular TXB2, did not significantly affect either CPAH or CIN; however, there was a strong trend toward improvement in CIN (from 1.23 +/- 0.11 ml/min to 1.43 +/- 0.15 ml/min (0.05 less than p less than 0.1). Neither drug affected renal hemodynamics in control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Hydroxyl radical scavengers ameliorate proteinuria in rat immune complex glomerulonephritis

We examined the effect of the administration of different oxygen radical scavengers on the development of glomerulonephritis induced by cationic bovine gamma-globulin (cBGG). Treatment with the H2O2 scavenger catalase or the superoxide anion (O2-) scavenger superoxide dismutase (SOD) did not significantly reduce proteinuria. In contrast, treatment with the hydroxyl radical (OH.) scavengers dimethyl sulfoxide (DMSO) or dimethylthiourea resulted in significant decrements in proteinuria, from 156 +/- 20 mg/24 hours in saline solution--treated control rats to 70 +/- 17 mg/24 hours (p less than 0.05) and 37 +/- 10 mg/24 hours (p less than 0.01) in DMSO- and dimethylthiourea-treated rats, respectively. Therapy with DMSO for 5 days after induction of glomerular disease also resulted in amelioration of proteinuria, 10.0 +/- 5.0 mg/24 hours versus saline solution-treated rats, 67.6 +/- 16.2 mg/24 hours (p less than 0.005). OH. scavenger therapy did not influence glomerular morphology, glomerular immunoglobulin G (IgG), or complement deposition, or creatinine clearances of rats with glomerulonephritis. Furthermore, there were no significant differences in serum levels of C3 and C5 or anti-BGG antibody production between DMSO-treated rats and control rats. None of the radical scavengers administered altered the enhanced glomerular thromboxane synthesis characteristic of this model. Our results suggest that OH. generation mediates in part glomerular injury in cBGG-induced glomerulonephritis.

Complement and leukocyte independent proteinuria and eicosanoid synthesis in rat membranous nephropathy

We examined the effect of complement depletion and leukocyte depletion on an experimental model of membranous nephropathy. Nephrosis was induced in 200-gm male Sprague-Dawley rats by priming with cationic bovine gamma-globulin in adjuvant on day 1 followed by intravenous challenge with antigen starting on day 10. No naive control rats had immunofluorescent deposits in glomeruli; urine protein was less than 10 mg/24 hour and glomerular thromboxane synthesis was 658 +/- 64 ng/mg glomerular dry weight. In contrast, all rats primed and challenged with cationic bovine gamma-globulin had intense granular capillary wall deposits of rats IgG, bovine gamma-globulin, C3 and C5; severe proteinuria (183 +/- 24 mg/24 hour) was observed, associated with a 3-fold increase in glomerular thromboxane (2,393 +/- 574 ng/mg, all p less than 0.01 versus naive controls). In some rats, administration of cobra venom factor and antiserum to rat C3, starting on day 8 was used to deplete complement; hemolytic C3 and C5 were less than 2% of normal at sacrifice. These rats had IgG and bovine gamma-globulin deposits, whereas they lacked glomerular C3 or C5. Proteinuria (209 +/- 28 mg/24 hour) and glomerular thromboxane (2,087 +/- 394 ng/mg) were markedly increased compared with control, but no different from normocomplementemic rats primed and challenged with cationic bovine gamma-globulin. In other rats, depletion of leukocytes was achieved by 1,000 R x-irradiation on day 7; at sacrifice, irradiated rats had 1,270 +/- 462 wbc/microliter versus 10,375 +/- 1,652 in nephrotic rats given no other treatment, with unaltered differentials. These rats had glomerular deposits of rat IgG, bovine gamma-globulin, C3 and C5 indistinguishable from nephrotic rats with normal leukocyte counts in intensity and distribution. Proteinuria (202 +/- 30) and glomerular thromboxane (2,358 +/- 189 ng/mg) were markedly elevated compared with naive controls, but were not different from the normocomplementemic or complement-depleted groups primed and challenged with antigen. An additional control group included rats primed with ovalbumin on day 1, irradiated with 1,000 R on day 7, and challenged with cationic bovine gamma-globulin starting on day 10. This group had granular capillary wall deposits of bovine gamma-globulin, but not deposits of IgG, C3, or C5; urine protein excretion (less than 10 mg/24 hours) and glomerular thromboxane synthesis (613 +/- 90) were not different from naive controls. Glomerular prostaglandin E2 synthesis did not differ among the five groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Suppression of neutrophil superoxide production by conventional peritoneal dialysis solution

The pH of conventional peritoneal dialysis solution is normally in the range of 5.0 to 5.5, because acid has been added during the manufacturing process to prevent caramelization of dextrose during sterilization. We studied the effects of normalizing the pH of conventional peritoneal dialysis solution on superoxide production by normal human neutrophils. At a pH of 6.0, superoxide generation was 4.07 +/- 2.56 (SD) nanomoles per million cells. With normalization of pH to 7.4, superoxide production was 19.3 +/- 7.3 (p less than 0.001). The results suggest that the unphysiologic acidity of conventional peritoneal dialysis solution has deleterious consequences on neutrophil superoxide formation.

Studies on malabsorption in malnourished Pakistani children

Malnutrition is a common finding in Pakistan especially in children of low socio-economic class. Impairment of digestion and absorption makes the diet inefficient at fulfilling the requirements of the child and leads to malnutrition. Earlier work from this laboratory has shown that feeding a high-protein diet to children suffering from protein-energy malnutrition (PEM) did not improve their condition. In the present study forty-two malnourished children and seventeen control subjects were investigated. They were divided into five groups, i.e. fibrocystic disease of the pancreas (n = 9), coeliac disease (n = 17), lactose intolerance (n = 5), PEM (n = 5) and nonspecific diarrhoea (n = 6) on the basis of history, clinical impression and biochemical findings. They were from 6 months to 12 years of age. The majority of them were suffering from diarrhoea, distension of the abdomen and retardation of growth. All children were physically examined and anthropometric measurements were recorded. Changes in hair in the form of sparseness, dyspigmentation and easy pluckability were observed in all groups. In PEM, 80% of the cases had enlarged livers. All children had reduced weight and height as compared with the control group. Haemoglobin, total protein and serum albumin showed a decrease and the fall was greatest in PEM cases as compared with the control group. The excretion of alpha-amino nitrogen increased in PEM children while hydroxyproline and creatinine levels showed a decrease as compared with the control group. The hydroxyproline index, which signifies the growth rate, was also significantly lower in all groups. Xylose and lactose tolerance tests were performed after an oral dose of xylose or lactose respectively. The xylose concentration after the test dose was reduced with the lowest values in the coeliac disease group as compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of diet on transaminase and arginase activities

The composition of the diet greatly influences the enzyme activities of the liver. The effect of low carbohydrate diet on AST, ALT and arginase activities in liver and serum of rats was determined in the present study. Liver ALT and serum AST were significantly increased in animals fed on low carbohydrate diet, the activities of other enzymes remained unchanged.

Increased leukotriene B4 synthesis in immune injured rat glomeruli

We examined glomerular synthesis of the 5-lipoxygenase metabolite, LTB4, in normal and immune-injured rat glomeruli. Glomeruli isolated from normal rats and from rats with nephrotoxic serum nephritis (NSN), passive Heymann nephritis (PHN) and cationic bovine gamma globulin (CBGG)-induced glomerulonephritis were incubated with the calcium ionophore A23187 (3 microM). Lipids in the glomeruli and media were extracted with ethyl acetate, and were purified and fractionated by HPLC. Immunoreactive-LTB4 (i-LTB4) was determined by radioimmunoassay on HPLC fractions with a detection limit of 50 pg of i-LTB4. A large peak of i-LTB4 that comigrated with authentic LTB4 was found exclusively in glomeruli isolated from the CBGG-injected rats. Addition of the lipoxygenase inhibitor BW755C (50 micrograms/ml) to glomerular incubation resulted in greater than 90% inhibition of i-LTB4. Synthesis of i-LTB4 by glomeruli from normal, NSN and PHN rats was undetectable. Glomerular LTB4 synthesis by CBGG-injected rats was confirmed by radiometric HPLC and by gas chromatography mass-spectroscopy (GC-MS) analysis. In order to rule out synthesis of LTB4 by neutrophils entrapped in the glomeruli, a group of rats received 1,000 rad total body x irradiation, with shielding of the kidneys before induction of CBGG glomerulonephritis. Despite greater than 95% reduction in total leukocyte count, glomerular synthesis of LTB4 remained enhanced. Augmented glomerular synthesis of the proinflammatory lipid, LTB4, in the CBGG model of glomerular disease could have an important role in the development of glomerular injury and proteinuria.

The roles of eicosanoids in experimental glomerulonephritis

There is accumulating evidence showing alterations of renal eicosanoid synthesis in glomerular disease. Despite the complexity of their role in glomerulonephritis, these compounds appear to play a major part in the inflammatory response and in control of renal hemodynamics. The role of eicosanoids in the filtration of macromolecules has not been established, but there is indirect evidence of their involvement in mediating proteinuria. Dietary manipulation, either by high EPA, high linoleic acid, or EFA-deficient diet, in experimental glomerulonephritis have shown promising results as summarized in Table 1. The therapeutic potential of alterations in dietary fatty acid to modulate the inflammatory response appears to be of great value. Table 2 summarizes the effects of different dietary fatty acid alterations on eicosanoid synthesis. Nonetheless, we should point out that most of the studies of alterations in dietary fatty acids did not document changes in glomerular synthesis of prostaglandin, thromboxane, or HETES. Further studies examining the effects of different fatty acid regimens on glomerular eicosanoid synthesis and the role of these eicosanoids in the development of glomerulonephritis will provide valuable information. These findings could determine the specific type of dietary manipulation to inhibit or stimulate the production of selected eicosanoids.

Immune complex effects on glomerular eicosanoid production and renal hemodynamics

We examined the effect of glomerular immune complex (IC) deposition on glomerular eicosanoid synthesis and the role of the eicosanoids in glomerular pathophysiology. Rats received daily 10 mg i.v. injections of native bovine gamma-globulin (NBGG) or cationic bovine gamma-globulin (CBGG) for 21 days; age-matched controls were maintained. Immunofluorescence and electron microscopy showed mesangial deposits of IC in the NBGG group and capillary wall deposits in the CBGG group, without light or electron microscopic evidence of leukocyte infiltration. One week after the last antigen dose, GFR was similar in all three groups, but RPF increased in the rats given CBGG; (8.37 +/- 0.90 vs. control 5.54 +/- 0.56 ml/min, P less than 0.05). Glomerular synthesis of prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) was normal in animals that received NBGG. Rats given CBGG had increased glomerular production of PGE2, (2.23 +/- 0.37 vs. control 1.03 +/- 0.16 ng/mg glomerular dry wt, P less than 0.05) and TxB2 (3.12 +/- 0.50 vs. control 0.48 +/- 0.07 ng/mg glomerular dry wt, P less than 0.001). Proteinuria only developed in the rats given CBGG, 86.6 +/- 18 mg/24 hr, which correlated with glomerular TxA2 synthesis, r = 0.82, P = 0.01. Acute administration of the TxA2 synthesis inhibitor, UK-38,485, and a TxA2 receptor antagonist, EP-092, to rats given CBGG did not affect GFR or RPF. The cyclo-oxygenase inhibitor, indomethacin, reduced both GFR and RPF by up to 40% in CBGG-immunized rats. Oral administration of UK-38,485 for six days to nephrotic rats did not result in a statistically significant reduction of proteinuria despite 85% inhibition of glomerular TxB2. We conclude that cationic antigen induces a glomerular disease pathologically similar to membranous nephropathy. The increment of RPF is most probably due to increased glomerular PGE2. The increased TxA2 has no effect on glomerular hemodynamics and probably is not a component in the pathogenesis of proteinuria.

Eicosanoids in experimental and human renal disease

The renal prostaglandins and thromboxanes are powerful autacoids with potential effects on renal hemodynamics, salt and water metabolism, and the immune system. The possibility of adverse effects on renal function in certain patients with renal disease due to cyclooxygenase inhibition with nonsteroidal anti-inflammatory drugs has long been appreciated. Experimental evidence indicates that renal prostaglandin and thromboxane production is increased in several models of renal disease and that similar decrements in renal function occur with cyclooxygenase inhibition and may be due to inhibition of vasodilator prostaglandins. Additionally, several investigators have shown that administration of prostaglandins may be therapeutic in some forms of renal disease, particularly immunologically mediated diseases. Dietary modification to affect prostaglandin production has also been promising in certain experimental models. In contrast to vasodilator prostaglandins, thromboxane is a potent vasoconstrictor and would be expected to have adverse effects on renal function. Despite demonstration of elevated glomerular thromboxane, studies using inhibitors of thromboxane synthesis in immunologically mediated glomerular disease have been disappointing. There is some evidence, however, that these drugs may be of benefit in ureteric obstruction and renal transplant rejection.

Glomerular arachidonate lipoxygenation in rat nephrotoxic serum nephritis

Arachidonate lipoxygenation to monohydroxylated eicosatetraenoic acids (HETE) was studied in rat nephrotoxic serum nephritis (NSN). A single infusion of nephrotoxic serum enhanced conversion of [3H]arachidonic acid ([3H]C20:4) to [3H]12-HETE in glomeruli isolated from nephritic rats compared with controls. The percent conversion of [3H]arachidonic acid was 1.95 +/- 0.2% in control glomeruli and 14.2 +/- 2% in nephritic glomeruli 2 d after induction of disease. No significant changes in the conversion of [3H]C20:4 to [3H]5-, 8-, and 9-HETE were noted. Extraction of glomerular HETE by alkaline hydrolysis, to evaluate possible reacylation of HETE after their production, confirmed the presence of 12-HETE and did not provide evidence of 5-HETE synthesis. Increased glomerular 12-HETE synthesis in nephritic rats was also demonstrated by high pressure liquid chromatography-UV detection and by 12-HETE radioimmunoassay. The enhanced glomerular 12-HETE synthesis commenced as early as 3-5 h after administration of nephrotoxic serum and peaked at day 2 with 10-fold enhancement of 12-HETE production. Increments of glomerular 12-HETE persisted on day 7 and returned toward control levels by day 14. Platelet depletion, induced by antiplatelet antisera, did not decrease glomerular 12-HETE synthesis in NSN, thereby eliminating platelets as the cellular origin of 12-HETE. Glomerular epithelial and mesangial cells are the most likely sources of enhanced 12-lipoxygenase activity. The enhanced arachidonate 12-lipoxygenation in glomerular immune injury could have important proinflammatory effects in the evolution of glomerulonephritis since 12-HETE has important effects on leukocyte function.

Second generation alpha-enones from a pyranosidic alpha-enone

The Diels-Alder product from the reaction of methyl 2,3,6-trideoxy-alpha-D-glycero-hex-2-enopyranosid-4-ulose (1b) with trans-1-methoxy-3-tert-butyl-dimethylsilyloxy-1,3-butadiene is 3b (93%). Reaction of 3b wih sodium borohydride causes reduction of the C-4 carbonyl group only, but, with lithium aluminum hydride, further reactions occur which can be rationalized by fragmentation brought about by hydride cleavage on the silicon-oxygen bond, with simultaneous ejection of the beta-methoxyl group complexed to a trivalent aluminum species. The enone resulting from this fragmentation also reacts further with lithium aluminum hydride, and several products result. The behavior of postulated intermediates, which have been prepared separately and subjected to the reaction conditions, supports the proposed reaction mechanisms. The "second generation" enone (methyl 2,3,6-trideoxy-alpha-D-talopyranosido)-[3,2-d]-2-cyclohexenone+ ++ (10a), arising from the first generation precursors 1b, has been prepare by two routes.

Studies on cataractogenesis in humans and in rats with alloxan-induced diabetes. I. Cation transport and sodium-potassium-dependent ATPase

Changes in the cation balance cause hydration and initiate the process of lens opacification. Such alterations were studied in human cataractous lenses and during the development of alloxan-induced diabetic cataract in rats by biochemical and histochemical techniques. The development of alloxan-induced cataract in rats was examined in vivo which showed cortical opacities beginning after 32 days. These opacities did progress to maturity after 64 days and finally the lenses were completely opacified after 96 days of alloxan treatment. The histochemical localization of sodium-potassium-activated adenosine triphosphatase using three different methods provided information on the possible role of this enzyme in normal and cataractous lenses. In human cataractous lenses, sodium-potassium adenosine triphosphatase activity was found to be considerably decreased, whereas no activity of this enzyme was localized in human diabetic cataractous lenses. An animal model provided evidence that an apparent decrease of sodium-potassium adenosine triphosphatase may be involved in the initiation of alloxan-induced diabetic cataract in rats.

Studies on cataractogenesis in humans and in rats with alloxan-induced diabetes. II. Histochemical evaluation of lenticular enzymes

The effect of cataractogenesis on the behavior of some enzymes involved in glucose metabolism was examined histochemically both in human lenses and in rat lenses from rats with alloxan-induced diabetes. Several modifications in the currently available techniques were made in order to localize glucose-6-phosphate dehydrogenase, aldose reductase, sorbitol dehydrogenase, hexokinase and ketohexokinase in ocular lens. Human cataractous lenses showed a precipitous drop in glucose-6-phosphate dehydrogenase activity, whereas the lenticular tissues of alloxan-treated rats showed a gradual decrease of this enzyme with the prolongation of diabetes. Aldose reductase activity increased in hypermature and senile diabetic cataracts, whereas sorbitol dehydrogenase activity decreased in these lenses. Similarly, in alloxan-diabetic rat lenses the activity of aldose reductase increased while that of sorbitol dehydrogenase decreased with the prolongation of diabetes. Attempts were made to localize hexokinase and ketohexokinase in ocular lens.

Mechanism of contamination from agricultural chemicals in mammals

Chemicals in the form of pharmaceuticals are used to extend the life of man. It is ironic that other chemicals are also required to poison the pests that compete for the food supply so that man will have enough to eat during his extended lifetime. Now these poisons are reaching levels in the environment where the life span of man is again being shortened by both immediate and long-term effects caused by these pesticides. Hundreds of thousands of people are incapacitated and killed by insecticide poisoning each year, many of them in developing countries, from the chemicals no longer allowed for use in the western nations that produce them. Continuous monitoring and surveillance are required to avoid misuse of pesticides, because many of the hazards associated with these chemicals can be reduced substantially, if not eliminated completely.

Trace elements in serum from Pakistani patients with acute and chronic ischemic heart disease and hypertension

We examined sera from 159 patients with ischemic heart disease and hypertension and from 50 apparently healthy control subjects for content of trace elements, cholesterol, triglyceride, and enzymes. Concentrations of copper, cobalt, cholesterol, and triglyceride were increased in all patients, but calcium was decreased in patients with hypertension, acute myocardial ischemia, and acute myocardial infarction. Also accompanying acute myocardial infarction were decreased concentrations of zinc and iron but increases in nickel, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase. Magnesium concentration was lower in patients with acute myocardial ischemia. In acute myocardial infarction, the concentrations of copper, zinc, and iron were higher after 21-30 h (as compared with the values at 0-10 h), by which time concentrations of calcium, magnesium, cobalt, and alanine aminotransferase had decreased. The variation in concentration of trace elements in serum from cases of ischemic heart disease and hypertension corresponds to the severity of the disorder.