Effect of liposome surface charge on the stability of technetium (99mTc) radiolabelled liposomes

Using liposomes radiolabelled by the 99mTechnetium-stannous chloride technique we have investigated the effect of surface charge on the stability of the isotope in vitro and in vivo. Dialysis of 99mTc-labelled positive, negative and neutral liposomes, which had been incubated in either saline or normal rat serum showed no significant loss of the isotope from the liposome surface with only 2 per cent of the isotope dialysed. A comparison of gel chromatography with dialysis confirmed that most of the isotope remained attached to the liposome surface, but it did reveal greater loss of the isotope, between 15 and 23 per cent. The liposome clearance rates obtained from 125I-egg phosphatidylcholine (EPC) and 99mTc dual-labelled positive or neutral liposomes were significantly different. The 99mTc marker was cleared five times faster from the positive liposomes and twice as fast from the neutral liposomes as the 125I-EPC integral membrane marker. The 99mTc attached to liposomes with a negative surface charge was stable in vivo and had the same clearance rate from the circulation as the 125I-EPC marker. These results indicate that the commonly used in vitro techniques for assessing liposome radiolabel stability are unsuitable for predicting the stability of the 99mTc in vivo.     

Stimulation of corticosterone secretion by the selective 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) in the rat

The selective 5-HT1A receptor agonist 8-OH-DPAT increased serum corticosterone concentration in rats in a dose-dependent manner. The synthetic corticoid dexamethasone lowered the serum corticosterone level and abolished its rise induced by 8-OH-DPAT. The corticosterone response to 8-OH-DPAT was also antagonized by spiperone, (+/-)- and (-)-pindolol and (+/-)-propranolol, all of which have been shown to have a high affinity for 5-HT1A receptors, though in most cases no complete blockade was found. A partial antagonism of the response was also observed after flumazenil, a benzodiazepine antagonist. On the other hand, the 5-HT1B receptor antagonist 21009, the 5-HT2 receptor antagonists ketanserin and pirenperone, the 5-HT3 receptor antagonist ICS 205-930, the alpha 2-adrenoceptor antagonists yohimbine and idazoxan, the beta-adrenoceptor blocker with no affinity to 5-HT1 receptors, atenolol, the dopaminergic antagonist pimozide, the histamine receptor blocker chloropyramine and the opiate receptor antagonist naloxone did not affect the hormonal response to 8-OH-DPAT. The 8-OH-DPAT-induced corticosterone secretion was not affected either in rats pretreated with p-chlorophenylalanine (PCPA, an inhibitor of tryptophan hydroxylase) or p-chloroamphetamine (PCA, a drug-inducing lesion of serotonergic nerve terminals). It is concluded that 8-OH-DPAT-induced increase in serum corticosterone concentration results from its action at a site different than the adrenal cortex and is mediated by postsynaptic 5-HT1A receptors, whereas other subtypes (5-HT1B, 5-HT2, 5-HT3) of 5-HT receptors do not participate in this response.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mathematically directed single-cut osteotomy for correction of tibial malunion

In 1986 and 1987, four patients with tibial malunion involving both angular and torsional misalignment underwent surgical correction by a single-cut technique based on a mathematical model of long bone deformity. The technique involved a single surgical cut, followed by rotation of the two fragments along the osteotomy plane. The orientation of the osteotomy is based on a computer-assisted design. The deformity is measured on radiographs, computed tomography, and clinical exam and is then plotted on graphs to find the osteotomy orientation. The deformity involved varus and extension in four cases, internal rotation in 2, and external rotation in two. The deformities ranged from 9 to 26 degrees. The cutting angle of the osteotomy ranged from 50 to 66 degrees as measured from the transverse plane. Actual lengthening of 1 cm and functional lengthening over 1.5 cm was obtained without the use of bone graft. As no wedge of bone was removed, all corrected bones were easily suited to rigid internal fixation across the cut surface. In all cases, the desired correction was obtained within measurable error, and union was obtained with minimal immobilization. There were no soft tissue or joint contractures, and no neurovascular complications. In one patient, who had had four prior surgical procedures on the involved limb, an infection developed 6 weeks postoperatively that required debridement and delayed primary closure. As the technique involves only one cut, no wedge of bone is removed, no shortening occurs, and the osteotomy is highly suitable for rigid internal fixation. The described technique is the first to integrate in a precise way the correction of torsion with the correction of angular deformity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Angiolymphoid hyperplasia with eosinophilia of the orbit associated with obstructive airway disease

Two patients with angiolymphoid hyperplasia with eosinophilia isolated to the orbit had eyelid swelling, a superior orbital mass, and histories of intermittent obstructive airway disease. One patient later developed a transient peripheral blood eosinophilia as high as 36%. One lesion recurred 38 months postoperatively and responded to systemic corticosteroid therapy.     

Effects of the novel antidepressant S-adenosyl-methionine on alpha 1- and beta-adrenoceptors in rat brain

alpha 1- and beta-adrenoceptors were studied ex vivo in the brains of rats receiving repeated daily treatment with the standard antidepressant imipramine or the atypical antidepressant S-adenosyl-L-methionine (SAM), which has minimal effects on monoamine reuptake or turnover. Consistent with past studies, a decrease in the density of beta receptors at three weeks and an increase in the affinity of alpha 1 receptors for the agonist phenylephrine at one week of treatment was observed with imipramine. By comparison, an increase in the density of beta receptors and a decrease in the affinity of alpha 1 receptors for phenylephrine was observed at one week of treatment with SAM. These changes were no longer apparent at three weeks of treatment. The results suggest that treatment with SAM does lead to changes in adrenergic neurotransmission, but that down regulation of beta receptors or increased agonist affinity of alpha 1 receptors may not be necessary for the production of antidepressant effects.     

Choreoacanthocytosis in a Chinese patient--a case report

A 50-year old Chinese woman with the rare neurological disorder of Choreoacanthocytosis is described. Her illness is characterised by seizures, buccolingual dyskinesia, choreiform movements, arreflexia and mild sensorimotor polyneuropathy. Acanthocytes were present in her peripheral blood in large numbers but the serum lipid profile was normal. Her features are consistent with those so far described in Caucasian and Japanese patients. The disease differs from Huntington's chorea in that there are acanthocytes, peripheral neuropathy, and metal function remains relatively intact.     

Schistosomiasis caused by Schistosoma mansoni in Baringo District, Kenya: case report

Schistosomiasis caused by Schistosoma mansoni has not been reported in Baringo District of Rift Valley Province. The intermediate host (Biomphalaria species) though has been reported to occur along the shores of the lakes in this region. Three children from Baringo District were diagnosed to have schistosomiasis caused by S. mansoni by finding ova in their stools. They gave no history of visiting an endemic area. There are many dams being built for land reclamation, creating favourable conditions for the spread of the disease, in presence of the intermediate and definitive host. Studies on the current status of the disease and malacology should be undertaken in order to control the spread of the disease at an early stage.