Particle release from haemodialysers

Release of particles from eight makes of hollow-fibre and one make of flatplate dialyser have been studied, and the relationship between rinsing volume and particles recovered established. In a supplementary study the effect on the number of particles released was assessed when striking the dialyser header during priming. Particle size distribution indicated that the majority of the particles recovered were less than 5 microns in diameter. A separate analysis of the particles in the 5-30 micron size range showed two different patterns of particle release. In the dialysers containing ethylene vinyl acetate (EVAL) or Cellulate the number of particles recovered were within the 95% range of the particles in the rinsing fluid and did not alter with increasing rinsing volume. In the dialysers containing Cuprophan and Hemophan the initial particle numbers were higher but fell rapidly up to a 450 ml rinse volume; increasing the rinse volume to 1050 ml did not alter particle recovery. Analysis of variance failed to differentiate between individual dialysers. Striking the header during priming resulted in a transient statistically nonsignificant increase in the number of particles recovered.

Combined endoscopic cytology and biopsies in the diagnosis of duodenal malignancy

The value of combined cytohistochemical examination in the diagnosis of malignant duodenal lesions was assessed in 78 patients with suspicious duodenal lesions seen at endoscopy. Cytological smears were taken using the direct-vision brushing technique and all were processed by the same experienced cytologist. Duodenal malignancy was confirmed histologically in four patients. Endoscopic biopsy was positive for malignancy in three of the patients and cytology was suspicious of malignant change in two patients and positive for malignant change in one patient. Cytology alone confirmed the diagnosis of malignancy in one patient. The cumulative diagnostic yield using both biopsy and cytology was 100%.

Administration of recombinant enkephalinase (neutral endopeptidase) prevents capsaicin-induced miosis in the rabbit eye in vivo

Substance P induced a dose-dependent contraction of iris sphincter muscles when applied in the presence of atropine to the isolated rabbit iris in vitro as evidenced by a decreased pupil diameter. Pretreatment of the iris with 20 micrograms of recombinant enkephalinase (neutral endopeptidase; EC 3.4.24.11) totally abolished the contractile response to substance P. Injection of 10 micrograms of capsaicin into the anterior chamber of atropine-treated rabbit eyes in vivo induced an immediate and intense miosis. Injection of 100 micrograms of recombinant enkephalinase, 1 or 5 min before capsaicin injection, significantly inhibited this miosis. This effect of enkephalinase was totally abolished by preincubating the enzyme with thiorphan, a high-affinity enkephalinase inhibitor. These results show that enkephalinase, which is known to hydrolyze substance P in vitro with high efficiency, also hydrolyzes endogenously released substance P in vivo. Furthermore, our results suggest that enkephalinase application may represent a novel therapeutic approach to treat substance P-mediated pathologies.

Pharmacokinetics of recombinant human tumor necrosis factor-alpha in rats. Effects of size and number of doses and nephrectomy

The serum pharmacokinetics of recombinant human tumor necrosis factor-alpha (rHuTNF) were determined in male and female rats under various conditions. The clearance of rHuTNF after iv administration was determined to be saturable over the dose range of 10-63 micrograms/kg. Multiple iv administration did not significantly change the clearance of rHuTNF. Nephrectomy significantly reduced but did not eliminate the clearance of rHuTNF. The data suggest that sites other than the kidney also contribute to the elimination of rHuTNF. Female rats showed significantly reduced clearance of rHuTNF compared to male rats at all doses after single and multiple iv administration in control and nephrectomized animals.

The influence of carbohydrate structure on the clearance of recombinant tissue-type plasminogen activator

Modification of the carbohydrate structures of recombinant tissue-type plasminogen activator (rt-PA) can increase or decrease its rate of clearance in rabbits. When rt-PA was treated with sodium periodate to oxidize carbohydrate residues, the rate of clearance was decreased from 9.6 +/- 1.9 ml min-1 kg-1 to 3.5 +/- 0.6 ml min-1 kg-1 (mean +/- SD, n = 5). A similar change in the clearance of rt-PA was introduced by the use of endo-beta-N-acetyl-glucosaminidase H (Endo-H), which selectively removes high mannose asparagine-linked oligosaccharides; the clearance of Endo-H-treated rt-PA was 5.0 +/- 0.5 ml min-1 kg-1. A mutant of rt-PA was produced with an amino acid substitution at position 117 (Asn replaced with Gln) to remove a potential glycosylation site that normally contains a high mannose structure. The clearance of this material was also decreased, similar to the periodate and Endo-H-treated rt-PA. Conversely, when rt-PA was produced in the CHO 15B cell line, which can produce only high mannose oligosaccharide structures on glycoproteins, the clearance was increased by a factor of 1.8. These results demonstrate that the removal of rt-PA from the blood depends significantly upon the nature of its oligosaccharide structures.

Development of partial tolerance to the gastrointestinal effects of high doses of recombinant tumor necrosis factor-alpha in rodents

Treatment of healthy rats and mice with a single intravenous injection of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) caused a dose-dependent gastrointestinal inflammation. Within 30 min gastric emptying was blocked and tissue edema occurred in the small and large intestine. In the cecum hemorrhage occurred after 4 h at doses greater than or equal to 250 micrograms/kg. The cecum exhibited an acute inflammatory response following rHuTNF-alpha treatment similar to that seen in tumor necrosis at the same dose. The vascular endothelium became swollen, increased numbers of neutrophils and other leukocytes attached to and penetrated the endothelium, and finally hemorrhage occurred. Treatment of rats with daily injections of rHuTNF-alpha (250 micrograms/kg per d) for 3 wk failed to produce cachexia. Within 24-48 h rats became resistant to the hemorrhagic effect of rHuTNF-alpha, however, the cytokine still caused a transitory block of gastric emptying after 10 d of treatment. Treatment at 5- or 10-d intervals produced results similar to the initial injection. These results suggest that maximum hemorrhagic response will occur when rHuTNF-alpha is administered at intervals of 5-10 d rather than daily.

Endophthalmitis associated with intravenous drug abuse

Endophthalmitis is an inflammation of the interior of the eye. We describe an IV drug abuser with endophthalmitis who initially was diagnosed as having an acute conjunctivitis. During the next 12 hours fulminant endophthalmitis developed. The patient failed to respond to treatment, and on the second hospital day underwent subtotal exenteration of the right orbit. The only organism obtained from numerous cultures was Staphylococcus epidermidis. We suspect the causative organism was not isolated.

Fatal hepatitis associated with diclofenac

Non-steroidal anti-inflammatory agents (NSAIDS) are a well recognised cause of hepatotoxicity. Diclofenac, a relatively new NSAID, was first introduced into the UK in 1979. Five cases of hepatitis have recently been reported, principally in the French literature. We report the first fulminant case of hepatitis in the English literature in a patient taking diclofenac and indomethacin.

[Absorption, distribution and elimination of a labelled extract of Ginkgo biloba leaves in the rat]

The absorption, distribution and elimination of a radiolabelled 14C extract prepared from Ginkgo biloba leaves have been studied in rats. Following oral administration, expired 14C-CO2 represented 16% of the administered dose excreted within the first 3 hours post-dose out of a total of 38% after 72 hours. An additional 21% of the administered dose was eliminated in the urine. The absorption of the radiolabelled Ginkgo biloba extract was at least 60%. The pharmacokinetics of the drug, based on blood specific activity data versus time course, were characteristic of a two-compartment model with an apparent first order phase and a biological half-life of approximatively 4.5 h. During the first 3 hours, radioactivity was primarily associated with the plasma, but through a gradual uptake after 48 h. The specific activity in erythrocytes matched that of plasma. A site of absorption in the upper gastrointestinal tract is suspected since specific activity in blood peaked after 1.5 hours. Glandular and neuronal tissues and eyes showed a high affinity for the labelled substance. These results provide the first tentative link between the therapeutic effectiveness of Ginkgo biloba extract and the biological fate of some of its constituents.

Postpericardiotomy syndrome in adults: incidence, autoimmunity and virology

While continuing a study of immunologic and virologic aspects of the postpericardiotomy syndrome (PPS) in infants and children, we undertook a companion study in adults. Whereas the incidence in 119 children was 27.8%, as is usual for our hospital, the incidence in 142 adults was 17.6%. Most of the operations (95 of 142) were performed on patients who were 50-69 years old. Incidence decreased as age increased: 28.5% for ages less than 40 years, 19.7% for ages 40--59 years, 14.2% for ages 60--69 years, and 10% for ages 70 years and older. Heart-reactive antibody in high titer was found in all patients with PPS; a rise in antiviral antibody to one or more of a battery of eight common viruses (adenovirus, cytomegalovirus, and coxsackie-virus B 1 to 6) was identified in 68% of these with PPS but in only 5% of those without clinical manifestations. We conclude that in adults, as in children, PPS may be an autoimmune phenomenon triggered by viral illness.

Patterns and intensity of autofluorescence and its relation to melanin in human epidermis and hair

The skin of 41 patients including 16 blacks, 15 Caucasians, and 10 Hispanics, was observed using a fluorescent microscope. Three patterns of autofluorescence were observed: intercellular, cytoplasmic, and a combination of intercellular and cytoplasmic. The hair of 75 subjects, including 18 Negroes and 55 Caucasians, was observed. Two patterns were found: medullar and at the cortex. Skin form black patients was associated with the cytoplasmic pattern of autofluorescence. Compared to lighter skin, black skin was also significantly associated with increased intensity of autofluorescence, indicating that autofluorescence of the epidermis parallels the clinical degree of pigmentation. In the hair of 75 subjects, similar results were obtained: Negro hair exhibited more fluorescence than Caucasian hair, and darker hair (brown to black) exhibited more fluorescence than lighter hair (blond). This may be related to melanin and it breakdown products.