Human biodistribution of an ultrasound contrast agent (Quantison) by radiolabelling and gamma scintigraphy

The biodistribution and kinetics of an air filled human serum albumin microcapsule formulation (Quantison) intended for use as an intravenous ultrasound contrast agent have been examined. 12 healthy subjects were administered with approximately 50 million microcapsules per kilogram body weight, radiolabelled with 50 MBq 123I. Imaging was performed over a period of 58 h using a large field-of-view gamma camera and the amount of labelled material present in the blood, urine and faeces measured. Imaging demonstrated that the liver was the organ with the highest uptake, with a mean uptake of 41.8% (SD 10.4%) of the administered dose 1 h following administration. The maximum uptake of the agent in the lungs was low, mean 4.0% (SD 3.4%). A small amount of uptake was visible in the bone marrow; however, this was not quantifiable. There was also evidence of minimal myocardial activity within 5 min of administration. No adverse events were observed and there were no changes in any of the individual post-study indices. The present study demonstrates the safety of Quantison. Gamma scintigraphy played a useful role in confirming the biodistribution of the agent with little lung uptake, high liver uptake and evidence of myocardial uptake.     

Disposition of the bromosulfophthalein-glutathione conjugate in the isolated perfused rat kidney

Renal elimination of the bromosulfophthalein-glutathione conjugate (BSP-GSH) after its i.v. administration in the rat in vivo is negligible. In our study we wanted to establish whether the high albumin-binding of BSP-GSH constitutes the major restrictive factor toward the urinary excretion of the compound. The renal disposition of BSP-GSH was studied in the isolated rat kidney during perfusions with or without albumin in the perfusate. The urinary clearance of BSP-GSH in the absence of albumin was very low (< 60 microliters/min) as compared to the inulin clearance (approximately 300 microliters/min). This indicates that albumin-binding is not the major reason for the low urinary clearance of BSP-GSH. Addition of albumin to the perfusate further decreased the urinary excretion by 60%. BSP-GSH is metabolized by the kidney into two major metabolites: the cysteinylglycine conjugate and the di-glutathione conjugate. Both metabolites appear in perfusate, which suggests that BSP-GSH undergoes tubular (re-)uptake. The di-glutathione conjugate is further metabolized to the di-cysteinylglycine conjugate. The di-glutathione conjugate and the di-cysteinylglycine conjugate are the major urinary components and the urinary elimination of BSP-GSH may depend on their formation. Inhibition of gamma-glutamyl transpeptidase activity with acivicin largely prevented the degradation to the cysteinylglycine and dicysteinylglycine conjugates of BSP. The total rate of urinary excretion, however, was only slightly lowered by acivicin. Apparently, cleavage of the gamma-glutamyl moiety is not relevant for the total urinary elimination of BSP-GSH.     

Output waveforms in the replay process in digital magneticrecording

The output voltage waveforms expected when replaying with various head structures from media magnetized in arbitrary directions are predicted. Expressions are given in useful closed forms for the outputs in isolated and pulse crowded circumstances. Output waveforms are shown for a range of orientations of the recorded magnetization to reveal aspects of pulse symmetry and their effects on “roll-off” curves     

Representation of a digital magnetic recording channel

A representation or model of a digital magnetic recording channel which has value both as an expression of the transfer characteristics of the channel and as a tool for use in the design and development of digital coding techniques for that channel is presented     

In vivo parathyroid hormone stimulates in vitro bone resorption by bovine monocytes

Cells of the monocyte-macrophage lineage have been thought to play a role in bone resorption. We examined the effects of in vivo administration of parathyroid hormone and 1,25-dihydroxyvitamin D3 on the ability of monocytes to degrade bone in vitro. Administration of parathyroid hormone for 4 d resulted in sustained hypercalcemia and a transient 1-d increase in plasma 1,25-dihydroxyvitamin D3. Parathyroid hormone significantly stimulated bone degradation by monocytes 2.6 times more than that of pretreatment controls. Parathyroid hormone treatment significantly enhanced (threefold) release of superoxide anion by monocytes stimulated with phorbol 12-myristate 13-acetate and increased migration of monocytes to bone particles in vitro. Continuous 7-d infusion of 1,25-dihydroxyvitamin D3 (50 micrograms/d) elevated plasma 1,25-dihydroxyvitamin D3 until infusions were discontinued. Increased 1,25-dihydroxyvitamin D3 was associated with hypercalcemia, which continued for several days postinfusion. In vivo administration of 1,25-dihydroxyvitamin D3 did not affect in vitro ability of monocytes to degrade bone. We concluded that in vivo administration of parathyroid hormone enhanced in vitro responsiveness of isolated monocytes in a manner consistent with a role for monocytes in bone remodeling. Furthermore, these data suggested that circulating monocytes could be a useful experimental model for further studies on parathyroid hormone responsiveness and bone resorption for the cow with milk fever.     

Entamoeba histolytica: computer-assisted modeling of phosphofructokinase for the prediction of broad-spectrum antiparasitic agents

Approximately 34 cases of intracranial tuberculomas with paradoxical response to antituberculous chemotherapy have been documented worldwide. In most of the previously reported cases of this entity an associated tuberculous meningitis has been reported. The majority of these patients were children or young adults, who had inoperably located intracranial tuberculomas in high risk regions developing a few weeks or months after the start of appropriate chemotherapy. 53% of them recovered completely, 37% improved with mild neurological deficits and 10% died. It is interesting that these intracranial tuberculomas developed or enlarged at a stage when systemic tuberculosis was being treated successfully. We report our recent experience with these potentially curable tumours of the central nervous system. The literature is reviewed and diagnostic and therapeutic considerations are discussed. The possible immunological mechanisms of this phenomenon are analysed. In conclusion, patients, who are suspected to be suffering from CNS-tuberculosis should receive a prolonged (12-30 months) course of effective antituberculous therapy. Evidence of new intracranial tuberculomas or the expansion of older existing lesions require no change in the antituberculous drug programme. In such cases systemic dexamethasone as adjuvant therapy for 4 to 8 weeks is worthwhile and effective. Surgical intervention may be necessary in situations with acute complications of CNS tuberculosis such as shunting procedures for the treatment of hydrocephalus. When the diagnosis is not firm and there is no response to therapy within 8 weeks, a stereotactic biopsy of a suspected tuberculoma should be performed. If the largest lesion is not located in high risk deep regions of the brain, it should be total removed surgically. With this combined management, a satisfactory outcome can be obtained in the majority of cases.     

Widely dispersed p53 mutation in respiratory epithelium. A novel mechanism for field carcinogenesis

Individuals with one aerodigestive tract malignancy have a high incidence of second primary aerodigestive tumors. The mechanism for this field effect has not been determined. We studied an individual with widespread dysplastic changes in the respiratory epithelium but no overt carcinoma. The entire tracheobronchial tree obtained at autopsy was embedded in paraffin, and bronchial epithelial cells were isolated by microdissection. DNA extracted from the microdissected cells was analyzed for point mutations in the p53 tumor suppressor gene. A single, identical point mutation consisting of a G:C to T:A transversion in codon 245 was identified in bronchial epithelium from 7 of 10 sites in both lungs. Epithelium at sites containing the p53 mutation was morphologically abnormal, exhibiting squamous metaplasia and mild to moderate atypia. No invasive tumor was found in the tracheobronchial tree or any other location. Cells from peripheral blood, kidney, liver, and lymph node exhibited no abnormality in the p53 gene. The widespread presence of a single somatic p53 point mutation in the bronchi of a smoker suggests that a single progenitor bronchial epithelial clone may expand to populate broad areas of the bronchial mucosa-a novel mechanism for field carcinogenesis in the respiratory epithelium that may be of importance in assessing individuals for risk of a second primary tumor as well as in devising effective strategies for chemoprevention of lung cancer.     

A ten-year experience in the evaluation and management of patients with stress urinary incontinence

The surgical procedures used, the complications encountered and the results obtained in 549 patients with urinary stress incontinence with or without prolapse and 50 patients with prolapse without urinary stress incontinence are presented. Incontinence was cured in 347 patients, improved in 126, unchanged in 66 and worsened in ten. Seven patients operated on for uterine prolapse developed urinary incontinence after surgery. The overall recurrence of SUI was 12.75%. The introduction of suprapubic bladder drainage has practically eliminated postoperative urinary tract infections and reduced the length of hospitalization from 9.1 to 7.2 days. My experience in 214 patients with suprabpubic drainage demonstratedthe superiority of the Ansari method over the cystocath. The addition of Cantor's bladder neck plication improved the results (cured plus improved) from 80% to 100% in the Marshall-Marchetti-Krantz operation and from 81% to 86% when the Marshall-Marchetti-Krantz operation was associated with an abdominal hysterectomy.