Screening for autism in young children with developmental delay: an evaluation of the developmental behaviour checklist: early screen.

The ability to identify children who require specialist assessment for the possibility of autism at as early an age as possible has become a growing area of research. A number of measures have been developed as potential screening tools for autism. The reliability and validity of one of these measures for screening for autism in young children with developmental problems was evaluated. The parents of 207 children aged 20-51 months completed the Developmental Checklist-Early Screen (DBC-ES), prior to their child undergoing assessment. Good interrater agreement and internal consistency was found, along with significant correlations with a clinician completed measure of autism symptomatology. High sensitivity was found, with lower specificity for the originally proposed 17-item screening tool and a five-item version.

Determination of apramycin in swine kidney tissue by liquid chromatography with fluorescence detection.

A liquid chromatographic method for determining apramycin in swine kidney tissue is described. Apramycin is extracted from tissue with basic methanol and purified by ion-pair extraction. By using an automated derivatization and injection procedure, the purified extract is derivatized with o-phthaldehyde, separated on a C18 column, and detected with a fluorescence detector. For fortified kidney samples, between-run coefficients of variation ranged from 4.8 to 7.1% at 1.00 ppm and from 9.6 to 14.3% at 0.50 ppm. Recoveries ranged from 76 to 86%. Standard curves were linear over the range 10-100 ng/mL.

Adenylyl cyclase activity in clonally derived human myoblast cultures: evidence for myoblast heterogeneity.

In vitro myogenesis recapitulates the programme of myogenesis in vivo. During the process of muscle differentiation, cAMP plays an important role in the control of gene expression and in the integration of metabolic functions. cAMP generation may be affected by drugs or hormones that interact with the membrane-bound enzyme adenylyl cyclase, including adrenergic agents and glucocorticoids. In this study, adenylyl cyclase activity was evaluated in membranes prepared from human clonally derived muscle cultures. In control cultures, there was considerable inter-clonal variation in basal, sodium-fluoride and forskolin-stimulated adenylyl cyclase activity. Cultures differed in their response to steroids: adenylyl cyclase activity was markedly enhanced in some clones, and was significantly inhibited in other clones. Pre-treatment of cultures with pertussis toxin indicated that the effects of steroids are mediated in part by modulation of G-protein activity. These findings indicate a substantial heterogeneity among myoblast clones with respect to the modulating effect of steroids on adenylyl cyclase activity. This observation may account for the conflicting reports of steroid effects on muscle in vitro, and may be of relevance to the understanding of possible transmembrane signalling alterations in muscle disease.

Systemic lupus erythematosus serositis.

The imaging appearances of a case of systemic lupus erythematosus, which manifested initially as a serositis, is described. Barium small bowel study showed segments of spiculation with tethering, angulation, and obstruction. On computed tomography there was ascites and segments of asymmetrical thickening of small bowel wall were observed. Laparotomy revealed extensive patchy serosal and peritoneal plaques but biopsy of these lesions did not lead to a definitive diagnosis. The diagnosis was made on the basis of marked elevation of antinuclear and anti-double stranded DNA antibodies.

Mammographic appearances of mammary duct ectasia that mimic carcinoma in a screening programme.

The aim of this study is to demonstrate the spectrum of mammographic appearances of mammary duct ectasia that mimic carcinoma in a breast cancer screening programme. Between February 1989 and March 1993, 40,003 women underwent screening mammography as part of the Western Australia Women's Cancer Prevention Unit screening programme. Fine needle aspiration or excisional biopsy was performed on 1437 women, and 12 cases of cytologically or histologically confirmed mammary duct ectasia were detected. A total of 14 mammographic abnormalities from 12 asymptomatic female patients were biopsied, and confirmed to represent mammary duct ectasia. The mammographic spectrum included eight areas of microcalcification (two of which were extensive), three spiculated masses and three lobulated, partially smooth masses. Five of these women showed no other mammographic stigmata of mammary duct ectasia in either breast. Additional features of mammary duct ectasia, including nipple retraction, retro-areolar duct dilatation or macrocalcification were identified in seven women. Mammographic features of mammary duct ectasia are frequently detected in asymptomatic women undergoing screening mammography and cause no diagnostic dilemma. Occasionally mammary duct ectasia will have a mammographic appearance that is indistinguishable from carcinoma, necessitating breast biopsy. In this study 40% of those women with mammary duct ectasia that were submitted for biopsy had no other feature of mammary duct ectasia that could have suggested the pre-operative diagnosis.

Calcified lymph node metastases in adenocarcinoma of the colon.

Radiologically demonstrable calcification has been described in a variety of primary tumours and metastatic deposits. Dystrophic calcification in retroperitoneal lymph nodes may occur in malignant lymphoma or metastatic carcinoma, most often after radiotherapy or chemotherapy. However, de novo calcification in retroperitoneal lymph node metastases from carcinoma are very rare. Such a case is presented here.

Physicochemical and pharmacokinetic parameters of seven lipophilic chlorambucil esters designed for brain penetration.

This report describes the physicochemical and pharmacokinetic parameters of seven chlorambucil esters, which were compared with those of chlorambucil. These esters were designed as chlorambucil prodrugs to increase the brain penetration and concentration vs time profile of chlorambucil within the CNS for potential treatment of brain tumors. They include four aliphatic esters from one to eight carbon chains in length (chlorambucil-methyl, -propyl, -hexyl, and -octyl esters) and three aromatic esters, including the phenylmethyl, phenylethyl and prednisolone ester of chlorambucil, prednimustine. The esters were lipophilic and possessed log octanol:water partition coefficients (log P values) that ranged from 4.05 to greater than 8.0. All retained alkylating activity, which was reduced compared with that of chlorambucil. In addition, all were metabolized in vivo in the rat to yield chlorambucil alone. Measurement of the in vitro rate of ester hydrolysis of the compounds to yield chlorambucil in rat plasma demonstrated that short-chain aliphatic and aromatic chlorambucil esters were rapidly broken down to their parent compound. The plasma half-lives of the compounds increased with the increasing length and complexity of their ester chain. This may have been related to an increase in the binding of the long-chain esters to plasma proteins, protecting the ester from nonspecific plasma esterases, and to a reduced affinity of plasma esterases to these esters. Pharmacokinetic analysis of chlorambucil-hexyl, -octyl, and -prednisolone esters by HPLC demonstrated that following their intravenous administration in the rat (in doses equivalent to equimolar chlorambucil, 10 mg/kg), they yielded only low concentrations of active compounds in plasma and brain. The brain:plasma ratio of these was low and similar to that of chlorambucil, and no ester demonstrated anticancer activity superior to that obtained after the administration of equimolar chlorambucil (5 mg/kg i.v., days 1-5) against brain-sequestered Walker 256 carcinosarcoma in the rat.

Pharmacokinetics of chlorambucil-tertiary butyl ester, a lipophilic chlorambucil derivative that achieves and maintains high concentrations in brain.

Equimolar doses of chlorambucil (10 mg/kg) and the lipophilic chlorambucil derivative, chlorambucil-tertiary butyl ester (13 mg/kg), were given i.v. to rats. Plasma and brain concentrations of chlorambucil and its active metabolites, 3,4-dehydrochlorambucil and phenylacetic mustard, as well as of chlorambucil-tertiary butyl ester were then determined by HPLC between 2 and 240 min after drug administration. Chlorambucil demonstrated a monophasic disappearance from plasma following its administration, with a half-life of 28 min. Significant amounts of phenylacetic mustard were detected after 15 min, and this agent maintained high levels of active compounds in plasma throughout the study. Only low concentrations of chlorambucil and phenylacetic mustard were detected in brain between 2 and 120 min. Following equimolar chlorambucil-tertiary butyl ester administration, it rapidly disappeared from plasma, with a half-life of approximately 2 min, and maintained low plateau concentrations between 15 and 120 min after treatment. It was not detected thereafter, although significant amounts of chlorambucil and phenylacetic mustard were detected throughout the study. Significant amounts of chlorambucil-tertiary butyl ester entered and remained within the brain, achieving a peak concentration at 15 min and disappearing thereafter with a half-life of 37 min. Low levels of chlorambucil and phenylacetic mustard were also detected. Calculated from the areas under the concentration vs time curves of total active compounds derived from chlorambucil and chlorambucil-tertiary butyl ester in brain and plasma, the brain:plasma concentration integral ratios were 0.018 and 0.68, respectively. Following equimolar doses of chlorambucil and chlorambucil-tertiary butyl ester, a 7-fold greater concentration integral was achieved by chlorambucil-tertiary butyl ester in brain at a 5-fold lower plasma concentration integral. Chlorambucil-tertiary butyl ester may be of value in the treatment of brain-sequestered tumors.

Cerebrospinal fluid monoamine markers are decreased in dementia of the Alzheimer type with extrapyramidal features.

We measured monoamine metabolites and biopterin in the CSF of 37 patients with dementia of the Alzheimer type (DAT), with or without extrapyramidal signs, and in 14 age-matched healthy controls. Compared with concentrations in DAT and controls, the concentrations of homovanillic acid (HVA) and biopterin were significantly decreased in DAT with extrapyramidal signs (EDAT). CSF 3-methoxy-4-hydroxy-phenethyleneglycol and 5-hydroxyindoleacetic acid did not differ significantly among these groups. Age at onset of dementia was positively correlated with CSF HVA (r = 0.49, p less than 0.05). The two dementia groups did not differ significantly in the extent of ventricular dilation as measured by quantitative CT, but EDAT patients had lower Mini-Mental State Examination scores than did DAT patients. When patients were matched for age and dementia severity, CSF HVA and biopterin concentrations remained significantly lower in EDAT than in DAT patients. These results indicate that EDAT patients form a distinct subgroup of DAT with evidence of central monoamine dysfunction.

Comparative brain and plasma pharmacokinetics and anticancer activities of chlorambucil and melphalan in the rat.

Equimolar doses of chlorambucil and melphalan (both 10 mg/kg) were administered i.v. to anesthetized rats, and the plasma and brain concentrations of chlorambucil, its metabolites 3,4-dehydrochlorambucil and phenylacetic mustard, and melphalan were determined by high-performance liquid chromatography from 5 to 240 min thereafter. Chlorambucil demonstrated a monophasic disappearance from plasma, with a half-life of 26 min. The compound was 99.6% plasma-protein-bound. Chlorambucil underwent beta-oxidation to yield detectable concentrations of 3,4-dehydrochlorambucil and substantial amounts of phenylacetic mustard in the plasma. Low concentrations of chlorambucil and phenylacetic mustard were detected in the brain. Calculated from the areas under the concentration-time curves, the brain:plasma concentration integral ratios of chlorambucil and phenylacetic mustard were 0.021 and 0.013, respectively. Melphalan demonstrated a biphasic disappearance from plasma, with half-lives of 1.9 and 78 min. The compound was approximately 86% plasma protein-bound. Low concentrations of melphalan were detected in the brain, and its brain:plasma ratio was 0.13. These data demonstrate that following the administration of chlorambucil and melphalan, only low concentrations of active drug are able to enter the brain. As a consequence, concentrations of both drugs that cause the complete inhibition of extracerebrally located tumor have no effect on those located within the brain. Further, the brain uptake of melphalan, although low, is greater than that of chlorambucil and its active metabolites, which coincides with its slightly greater intracerebral activity following the systemic administration of very high doses.

Facilitated transport of melphalan at the rat blood-brain barrier by the large neutral amino acid carrier system.

Melphalan has been reported to be actively transported into tumor cells by two amino acid carrier systems. As amino acids are transported across cerebral capillaries by a facilitated mechanism, studies were undertaken to assess whether or not melphalan was transported similarly, and additionally to determine melphalan's plasma and brain pharmacokinetics. The brain uptake of [14C]melphalan was measured by an in situ brain perfusion technique in the anesthetized rat utilizing [14C]-melphalan. The cerebrovascular permeability-surface area product of [14C]melphalan was calculated at cold melphalan concentrations from O to 16.3 mumol/ml. The permeability-surface area product was concentration dependent and decreased from 10.8 +/- 0.6 (+/- SE) X 10(-4)S-1 at 0.02 mumol/ml melphalan to 5.4 +/- 0.3 X 10(-4)S-1 at 16.3 mumol/ml. The system became saturated at a concentration in excess of 0.1 mumol/ml. The Michaelis-Menten parameters Vmax and Km, determined by nonlinear regression analysis of the permeability-surface area product data, equaled 0.9 +/- 0.3 X 10(-4) mumol/s/g and 0.15 +/- 0.06 mumol/ml, respectively, for the saturable component of melphalan's brain uptake. The Kd of the nonsaturable component was 5.3 +/- 0.03 X 10(-4)S-1. Addition of the amino acid 1-phenylalanine to the brain perfusate inhibited the saturable component of melphalan's brain uptake. The analysis of the plasma and brain concentrations of melphalan by high-performance liquid chromatography, following i.v. melphalan administration, demonstrated that approximately 15% of the drug that was present in plasma entered the brain. These data suggest that the brain uptake of melphalan is facilitated, demonstrating concentration-dependent uptake, saturation, and inhibition, and that melphalan shares the large neutral amino acid carrier system at the blood-brain barrier.

Melphalan concentration dependent plasma protein binding in healthy humans and rats.

The binding of melphalan to plasma proteins from four healthy humans and from rats was measured by centrifugal ultrafiltration. Melphalan concentrations were determined by HPLC and by measuring 14C-melphalan activity. In whole blood, melphalan was distributed preferentially in plasma. However, a constant fraction, 37%, which was independent of the total melphalan concentration in whole blood, was present within the red blood cells. The binding of melphalan to plasma proteins from humans was less than that from rats. In both, however, the fraction bound was constant throughout the concentration range (0.1 to 9.0 microM) that is achieved during standard-dose melphalan therapy. Albumin was the primary binding protein. At concentrations equal to or in excess of 33 microM, which have been achieved during high-dose melphalan therapy, free plasma melphalan concentrations were no longer linearly related to total drug concentrations, and the plasma protein binding of melphalan in the human became concentration dependent. This occurred at concentrations of 70 microM in the rat. Scatchard analysis of the data indicated the presence of 2 groups of binding sites. Class I sites had 0.03 and 0.4 binding sites per albumin molecule in humans and rats, with respective association constants of 4.43 X 10(4) M-1 and 1.92 X 10(4) M-1. Class II sites had 5.18 and 2.60 binding sites per molecule, with respective association constants of 3.82 X 10(2) M-1 and 2.01 X 10(2) M-1.

Regional cerebrovascular transport of leucine as measured by the in situ brain perfusion technique.

Leucine influx into six brain regions was determined in anesthetized rats with the in situ brain perfusion technique using either saline or plasma perfusate. This technique has several advantages over other methods such as the brain uptake index (BUI) technique. The concentration dependence of L-leucine influx was best described by a model with a saturable and a nonsaturable component. For the saturable component, Vmax equaled 10.67 +/- 0.21 X 10(-4) mumol s-1 g-1 and Km equaled 0.0257 +/- 0.0009 mumol ml-1, whereas the constant of nonsaturable diffusion (Kd) equaled 0.957 +/- 0.067 X 10(-4) s-1 in the parietal lobe during saline perfusion. Vmax was higher in the cortical lobes than in other brain areas, probably owing to a greater capillary surface area. There were no regional differences in Km or Kd. The apparent Km for L-leucine during plasma perfusion was 20 times greater than the Km during saline perfusion, and 3 to 4 times greater than the plasma leucine concentration, owing to competitive inhibition of leucine transport by other large neutral amino acids in plasma. These results for Vmax, Km, and Kd differ by three- to fourfold from previous estimates obtained with the BUI technique. The high apparent Km during plasma perfusion indicates that leucine influx is a linear function of plasma concentration up to 0.5 mumol ml-1 when the plasma concentrations of other amino acids remain constant, whereas influx would be approximately constant when plasma concentrations of all large neutral amino acids increased or decreased by a constant fraction.

Inability of dimethyl sulfoxide to increase brain uptake of water-soluble compounds: implications to chemotherapy for brain tumors.

There is conflicting evidence as to whether dimethyl sulfoxide (DMSO) can reversibly open the blood-brain barrier and augment brain uptake of water-soluble compounds, including anticancer agents. To investigate this, 125I-human serum albumin, horseradish peroxidase, or the anticancer drug melphalan was administered iv to rats or mice, either alone or in combination with DMSO. Some animals received an additional ip priming dose of DMSO. The regional brain concentrations of each substance were measured after the animals were killed. DMSO administration did not significantly increase the brain uptake of any of the compounds as compared to control uptakes. These results do not support prior reports that DMSO increases the permeability of water-soluble agents across the blood-brain barrier.

Methadone in brain and its effects on locomotor activity of young and aged mice.

Plasma and brain levels of methadone produced by subcutaneous injections of the chloride salt (7.5, 15.0 or 22.5 mg/kg) and resultant changes in locomotor activity were determined in young (6-8 months) and aged (30-32 months) C57BL/6J mice. Methadone elevated locomotor activity of young and aged mice above control levels to about the same extent. The degree of activity elevation was inversely related to dose for both age groups, however, the reduction in stimulation with increasing dose was greater for young than aged mice; and only young mice exhibited a significant biphasic response to the high drug dose. Although the behavioral results suggest that aged mice were less responsive than young mice to methadone, brain concentrations of the drug were higher in aged than young mice by approximately one hour after injection. The age difference noted in brain concentration was not observed for plasma levels of methadone; hence cannot be accounted for by reduced drug metabolism in aged mice. The results of this study indicate that compared to young adults, aged mice are less responsive behaviorally to methadone despite higher brain concentrations of the drug.

Phenobarbital pharmacokinetics in rat as a function of age.

Biodisposition of phenobarbital was examined in male Fischer-344 rats of different ages (3-4, 11-12, 23-24, and 32-34 months). Phenobarbital was administered intraperitoneally as a bolus (20 mg/kg) or continuously for 5 days from an implanted osmotic minipump (4.73 mg/day). Phenobarbital concentrations were determined by gas chromatography with a nitrogen-selective detector after extraction from plasma, plasma ultrafiltrate, and brain (cortex and cerebellum). Higher plasma and brain concentrations were found in the aged animals after a bolus injection or during continuous administration, and were related to decreases in the apparent plasma clearance of the drug. Apparent clearance was greater during continuous administration than following a bolus in 3- to 4-month- and in 32- to 34-month-old rats, which suggested autoinduction of phenobarbital metabolism. In addition, the plasma/brain distribution ratio of phenobarbital was elevated in the older animals.

Age effects on haloperidol pharmacokinetics in male, Fischer-344 rats.

Biodisposition of haloperidol was examined in male, Fischer-344 rats in four age groups, 3 to 4, 11 to 12, 23 to 24 and 32 to 34 months. Haloperidol was administered i.p. as a bolus (0.50 mg/kg) or continuously during 4 days from an implanted osmotic minipump (0.15 mg/day). Plasma and regional brain concentrations of haloperidol were determined by gas chromatography with a nitrogen-phosphorus detector. After a bolus administration, plasma and brain concentrations were significantly higher at later time points, the plasma elimination half-life was significantly longer and the estimated plasma clearance was lower in 32- to 34- than in 3- to 4-month-old animals. The plasma and regional brain concentrations 6 hr after a bolus increased as a function of age, up to 23 to 24 months. At a steady state after continuous infusion, plasma and brain concentrations also rose with age up to 23 to 24 months. After either bolus or continuous infusion, the brain/plasma concentration ratios were lower at 11- to 12- and 23- to 24-months-of-age than at either of the other age groups. The results indicate that a reduced apparent plasma clearance of haloperidol is primarily responsible for higher plasma and brain concentrations of haloperidol in the older animals and that plasma concentrations are not always predictive of brain concentrations.