Autoregulation of blood flow to choroid plexus of rabbits

Blood flow to the choroid plexus (CP) of rabbits was measured before and during an increase in arterial pressure (AP). Blood flow returned to control levels in the CP of the lateral and fourth ventricles of the brain when AP was increased 63% by i.v. infusion of norepinephrine. However, when AP was increased 68% by occlusion of the descending thoracic aorta, blood flow to the CP of the fourth ventricle remained elevated, while blood flow to the CP of the lateral ventricles returned to the control level. Our findings suggest that blood flow to the CP of the lateral ventricles autoregulates during nonpharmacological or pharmacological increases in AP, while blood flow to CP of the fourth ventricle does not autoregulate during nonpharmacological increases in AP.

Effect of desonide ointment, 0.05%, on the hypothalamic-pituitary-adrenal axis of children with atopic dermatitis

Desonide ointment has demonstrated a good safety and efficacy profile during the many years it has been used in treating dermatoses. However, there have been no controlled clinical trials to evaluate its systemic safety when used in treating children. Suppression of the hypothalamic-pituitary-adrenal (HPA) axis can occur after repeated application of topical corticosteroids. In general, the degree of suppression of the HPA axis function is related to the daily dosage of steroid given, the duration of its administration, the extent of body surface covered, and the potency of the corticosteroid. This study sought to determine the comparative effects of 0.05 percent desonide and 2.5 percent hydrocortisone ointments on the HPA axis of children with atopic dermatitis. There was no suppression of early morning cortisol in either treatment group. The ACTH-stimulated mean cortisol values after four weeks of treatment were not significantly different from the baseline values for either treatment group. We conclude that neither 0.05 percent desonide ointment nor 2.5 percent hydrocortisone ointment compromised the HPA axis of children with atopic dermatitis treated topically for four weeks.

Dwarfism in Dexter cattle is not caused by the mutations in FGFR3 responsible for achondroplasia in humans

Dexter cattle carry a genetic defect causing a dwarf phenotype in the heterozygotes (Dx+/-), while homozygotes (Dx+/+) are stillborn with extreme shortening of limbs and gross craniofacial defects and are described as 'bulldog' calves. The heterozygous phenotype has been likened to achondroplastic dwarfism in humans (ACH), which has recently been shown to be the result of mutations in the transmembrane region of the fibroblast growth factor receptor 3 (FGFR3) gene. We have sequenced the transmembrane region of bovine FGFR3 from normal Dexter cattle (Dx-/-) and bulldog calves (Dx+/+). The sequence from both is identical and therefore excludes mutations in the trans-membrane region of FGFR3 as the cause of Dexter dwarfism.

Symmetrical synovial fluid cell cytokine messenger RNA expression in rheumatoid arthritis: analysis by reverse transcription/polymerase chain reaction

To investigate the complex intra-articular immune activity in rheumatoid arthritis (RA), we analysed the expression of a wide range of cytokine mRNAs in synovial fluid cells from patients with rheumatoid arthritis. To minimize in vitro artefact, mRNA was rapidly extracted from synovial fluid leucocytes taken from single joints of seven patients and simultaneously from both knee joints of four patients. Expression of interleukin (IL) 1 beta, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, tumour necrosis factor-alpha and interferon-gamma (IFN-gamma) was detected using the reverse transcription/polymerase chain reaction. The expression of cytokines varied between patients. IFN-gamma mRNA was detected in 60% of the patients and IL-4 mRNA in 10%. Cytokine expression in both knees was very similar. These results suggest that T-cell activity in RA is detectable using sensitive techniques and that the intra-articular immunopathology of RA is systemically very similar.

Cosmid-derived markers anchoring the bovine genetic map to the physical map

The mapping strategy for the bovine genome described in this paper uses large insert clones as a tool for physical mapping and as a source of highly polymorphic microsatellites for genetic typing, and was one objective of the BovMap Project funded by the European Union (UE). Eight-three cosmid and phage clones were characterized and used to physically anchor the linkage groups defining all the bovine autosomes and the X Chromosome (Chr). By combining physical and genetic mapping, clones described in this paper have led to the identification of the linkage groups corresponding to Chr 9, 12, 16, and 25. In addition, anchored loci from this study were used to orient the linkage groups corresponding to Chr 3, 7, 8, 9, 13, 16, 18, 19, and 28 as identified in previously published maps. Comparison of the estimated size of the physical and linkage maps suggests that the genetic length of the bovine genome may be around 4000 cM.

A medium-density genetic linkage map of the bovine genome

A cattle genetic linkage map was constructed which covers more than 95 percent of the bovine genome at medium density. Seven hundred and forty six DNA polymorphisms were genotyped in cattle families which comprise 347 individuals in full sibling pedigrees. Seven hundred and three of the loci are linked to at least one other locus. All linkage groups are assigned to chromosomes, and all are orientated with regards to the centromere. There is little overall difference in the lengths of the bull and cow linkage maps although there are individual differences between maps of chromosomes. One hundred and sixty polymorphisms are in or near genes, and the resultant genome-wide comparative analyses indicate that while there is greater conservation of synteny between cattle and humans compared with mice, the conservation of gene order between cattle and humans is much less than would be expected from the conservation of synteny. This map provides a basis for high-resolution mapping of the bovine genome with physical resources such as Yeast and Bacterial Artificial Chromosomes as well as providing the underpinning for the interpolation of information from the Human Genome Project.

Kinematics of the glenohumeral joint: influences of muscle forces, ligamentous constraints, and articular geometry

Despite recent interest in the study of shoulder kinematics, there is considerable controversy in the literature regarding translations at the glenohumeral joint. The purpose of this study was to investigate the key factors that control shoulder motions, thus leading to a better understanding of joint function. Translation and rotation patterns were studied in fresh-frozen glenohumeral joints of human cadavers with a six-degrees-of-freedom magnetic tracking device. Shoulders were positioned from maximal internal to external rotation at several arm positions (various elevations and planes of motion). In order to determine the effect of muscle forces, joints were positioned both actively and passively. Additionally, articular surface geometry and ligament origin-insertion wrap lengths were measured to assess their influences on joint kinematics. When joints were positioned passively, large translations were observed at the extremes of motion. With active positioning, muscle forces tended to limit humeral head translations, principally by restricting rotational ranges of motion. However, when data from the passive model were reanalyzed by considering only the rotational ranges of motion seen actively, no significant differences in translation were found between the two models. Joint conformity was found to have a significant influence on translations during active positioning but not during passive positioning. Glenohumeral ligament wrap lengths, however, correlated with translations when joints were positioned passively but not when positioned actively. Findings from this study emphasize the importance of muscle forces in keeping the humeral head centered in the glenoid. Although large translations are possible, they can be achieved only with increases in rotational ranges of motion associated with the removal of muscle force. Additionally, joint conformity appears to play a role in controlling translations during active motions, whereas capsular constraints become more important during passive motions.

Predicting long-term performance of irradiation polymers

Material degradation occurs during and after irradiation sterilization. The degree of post-degradation can be accelerated by altering the temperature, environment, and irradiation dose. This article discusses methods to accelerate post-degradation and how this can be used as a predictive technique for evaluating new or improved polymer formulations.

Bronchopulmonary foregut malformation mimicking neuroblastoma

We report the case of a patient with an unusual, complex bronchopulmonary foregut malformation. The malformation included an extralobar sequestration, an esophageal duplication cyst, and a gastric duplication cyst. Postnatal imaging suggested a fetal adrenal neuroblastoma.

The biochemical pathway mediating the proliferative response of bone cells to a mechanical stimulus

Calvarial bone cells of rats were subjected to either a cyclic biaxial strain of 0.17 per cent (1700 microstrain) or a hydrostatic pressure of 2.5, five, or ten pounds per square inch (17.2, 34.5, or sixty-nine kilopascals). The frequency was held constant at one hertz for both types of mechanical stimulation. When cultured bone cells that had been subjected to a cyclic biaxial strain for two hours were harvested twenty-two hours later, it was found that the level of prostaglandin E2 had increased significantly (p < 0.01) as had cellular proliferation (p < 0.01), as indicated by the incorporation of [3H]-thymidine. The addition to the medium of indomethacin, an inhibitor of prostaglandin synthesis, at a ten-micromolar concentration significantly inhibited (p < 0.01) the increase in prostaglandin E2 synthesis but had no effect on the strain-induced increase in cellular proliferation, as indicated by the incorporation of [3H]-thymidine. Twenty-four hours after exposure to the same cyclic biaxial strain for thirty seconds, other cultured bone cells showed a significant increase in the level of cytoskeletal calmodulin (p < 0.05) and in the DNA content (p < 0.05). N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7), a calmodulin antagonist, was added to the medium at a one-micromolar concentration, which had been shown to have no effect on the increase in the DNA content of control cells; W-7 completely blocked the increase in the level of cytoskeletal calmodulin and in the DNA content in the cells that were subjected to a cyclic biaxial strain. The bone cells subjected to a hydrostatic pressure showed a dose-dependent increase in the concentration of cytosolic Ca2+, as measured with Fura 2-AM, a fluorescent indicator of intracellular calcium. With a pressure of ten pounds per square inch (sixty-nine kilopascals), the increase in the concentration of cytosolic Ca2+ was nearly eight times greater than that at 2.5 pounds per square inch (17.2 kilopascals) (126 +/- 15.2 compared with 16 +/- 8.0 nanomolar, mean and standard deviation). The addition to the medium of neomycin, an inhibitor of the inositol phosphate cascade, at a ten-millimolar concentration completely blocked the increase in the concentration of cytosolic Ca2+ in these cells; this concentration of neomycin had been shown to have no effect on proliferation in control bone cells. There was also a dose-dependent relationship between the duration of the stimulus and the cellular proliferation. Remarkably, one cycle of pressure at ten pounds per square inch (sixty-nine kilopascals) and a frequency of approximately one hertz produced a 57 per cent increase in the incorporation of [3H]-thymidine at twenty-four hours (p < 0.001). From these findings, we hypothesized that the inositol phosphate cascade-cytosolic Ca(2+)-cytoskeletal calmodulin system plays a dominant role in the signal transduction of a mechanical stimulus into increased proliferation of bone cells, at least under the conditions reported here.

Neonatal gastrointestinal imaging

As an aid to practicing neonatologists, the many gastrointestinal anomalies and diseases found in neonates are discussed with regard to choosing the most efficient and appropriate imaging modalities in each. The discussion is organized under anatomical headings: esophagus, stomach, small bowel, colon, liver, and miscellaneous. Nine representative images are included as illustrations. There is a brief discussion of umbilical arterial and venous catheters.

Mottle on computed radiographs of the chest in pediatric patients

PURPOSE

To investigate the relationship between radiation exposure and perceived mottle at bedside pediatric chest examinations performed with screen-film and computed radiographic techniques.

MATERIALS AND METHODS

In a pediatric intensive care unit, chest radiographs were obtained with both computed radiography (60 radiographs) and a 600-speed screen-film system (14 radiographs). The relative radiation exposure was estimated by using the sensitivity value obtained in the processing of each computed radiograph. Five radiologists assessed the mottle present in the computed radiographs and screen-film images.

RESULTS

For computed radiographs, the perceived level of mottle was inversely related to radiation exposure. For the same radiation exposure, the perceived mottle on computed radiographs was significantly higher than that on screen-film images (P < .001 for small cassettes; P < .01 for large cassettes).

CONCLUSION

Pediatric computed radiography of the chest requires approximately twice the exposure of a 600-speed screen-film system to attain the same level of mottle.

The effect of intravesical mitomycin C on recurrence of newly diagnosed superficial bladder cancer: a further report with 7 years of follow up

PURPOSE

We determined the role, if any, of 1 and 5 instillations of intravesical mitomycin C in the treatment of newly diagnosed superficial bladder cancer.

MATERIALS AND METHODS

A multicenter randomized clinical trial was done involving 502 patients with newly diagnosed superficial bladder cancer. After complete transurethral resection patients with newly diagnosed superficial bladder cancer. After complete resection patients were randomized into 1 of 3 treatment arms: no further treatment, 1 instillation of mitomycin C at resection and 1 instillation at resection and at 3-month intervals for 1 year (total 5 instillations). The dose of mitomycin C used was 40 mg./40 ml. water. End points were interval to first superficial recurrence, recurrence rate (defined as the number of positive cystoscopies per year) and progression-free interval rate (progression defined as the development of muscle invasive or metastatic disease, or death from bladder cancer).

RESULTS

After median followup of 7 years 1 and 5 instillations of mitomycin C resulted in decreased recurrence rates and increased recurrence-free interval. The benefit of mitomycin C was observed in patients at low, medium and high risk for subsequent recurrence. There was suggestive but not conclusive evidence that 5 instillations of mitomycin C offered a slight advantage over 1 instillation.

CONCLUSIONS

Our analysis confirms the positive benefit of mitomycin C to decrease the number of subsequent recurrences and increase the recurrence-free interval.

Altered expression of class I major histocompatibility antigens on bovine cells infected with the protozoan parasite Theileria annulata

Theileria annulata infection is controlled by MHC class I restricted cytotoxic T cell killing of infected cells. The long term persistence of parasite suggests that it employs a mechanism to avoid immune surveillance. In this paper we describe the modification of BoLA class I antigens on the surface of Theileria annulata transformed lymphoblastoid cells. The extent of modification is different between individuals varying from extensive to undetectable.

Pulsatile perfusion system for ex vivo investigation of biochemical pathways in intact vascular tissue

We have constructed and performed initial validation of an innovative perfusion system that allows exposure of intact segments of vascular tissue to realistic physiological and hemodynamic environments ex vivo. Computer-controlled opening and closing of an in-line gate valve allows generation of arterial pressure waveforms. The control algorithm predicted resultant pressure waveforms with a high degree of accuracy (Pearson correlation coefficient > 0.97). To document vascular homeostasis ex vivo, vasomotor bioassays and morphological studies were performed. The bioassays consisted of injecting epinephrine (2 x 10(-3) mg/ml) into the perfusion system followed by acetylcholine (100 microM) while concurrently measuring vessel diameter with a laser micrometer, significant vasomotion was measured for canine carotid arteries (n = 4) bioassayed after 1, 24, and 48 h of perfusion (P < 0.03). Additionally, human saphenous vein segments were perfused for 24 h (n = 4) and viewed with laser confocal scanning microscopy and transmission electron microscopy; photomicrographs show typical vascular morphology. We conclude that the vascular perfusion system described herein is well suited for investigating the response of intact vascular tissue to hemodynamic variables.

Novel alterations in CDK1/cyclin B1 kinase complex formation occur during the acquisition of a polyploid DNA content

The pathways that regulate the S-phase events associated with the control of DNA replication are poorly understood. The bone marrow megakaryocytes are unique in that they leave the diploid (2C) state to differentiate, synthesizing 4 to 64 times the normal DNA content within a single nucleus, a process known as endomitosis. Human erythroleukemia (HEL) cells model this process, becoming polyploid during phorbol diester-induced megakaryocyte differentiation. The mitotic arrest occurring in these polyploid cells involves novel alterations in the cdk1/cyclin B1 complex: a marked reduction in cdk1 protein levels, and an elevated and sustained expression of cyclin B1. Endomitotic cells thus lack cdk1/cyclin B1-associated H1-histone kinase activity. Constitutive over-expression of cdk1 in endomitotic cells failed to re-initiate normal mitotic events even though cdk1 was present in a 10-fold excess. This was due to an inability of cyclin-B1 to physically associate with cdk1. Nonetheless, endomitotic cyclin B1 possesses immunoprecipitable H1-histone kinase activity, and specifically translocates to the nucleus. We conclude that mitosis is abrogated during endomitosis due to the absence of cdk1 and the failure to form M-phase promoting factor, resulting in a disassociation of mitosis from the completion of S-phase. Further studies on cyclin and its interacting proteins should be informative in understanding endomitosis and cell cycle control.

The spin trap reagent PBN attenuates degeneration of 5-HT neurones in rat brain induced by p-chloroamphetamine but not fenfluramine

Dark Agouti rats injected with either p-chloroamphetamine (PCA; 2.5 mg/kg i.p.) or fenfluramine (15 mg/kg i.p.) had substantial decreases (approximately 50%) in the concentration of 5-HT and 5-HIAA and binding of [3H]paroxetine in the cerebral cortex 7 days later. This indicates that both compounds had produced neurodegeneration of 5-HT axon terminals. Two doses of alpha-phenyl-N-tert-butyl nitrone (PBN; 150 mg/kg i.p.) 130 min apart had no effect on cortical 5-HT content or [3H]paroxetine binding. However, when PBN (150 mg/ kg) was given 10 min before and 120 min after PCA (2.5 mg/kg) it attenuated the PCA-induced neurodegeneration. In contrast, PBN was without significant effect on the fenfluramine-induced damage. Changes in rectal temperature following either the neurotoxins or neurotoxins+ PBN were no more than +/-1 degree C of saline-injected control rats. These data indicate that PCA, like MDMA, probably induces neurotoxic degeneration because of the formation of catechol or quinone metabolites and subsequent reactive tree radical formation. Such a mechanism does not appear to explain fenfluramine-induced damage to 5-HT neurones.

The CAT-Tox (L) assay: a sensitive and specific measure of stress-induced transcription in transformed human liver cells

Identifying and measuring the molecular mechanisms of toxicity is an important goal in hazard assessment. We have developed an assay in transformed human liver cells to simultaneously measure the transcriptional responses of 14 stress promoter- or response element-chloramphenicol acetyl transferase (CAT) fusion constructs that are stably integrated into the HepG2 cell line. This assay can measure a wide spectrum of stresses, both toxic and nontoxic, such as protein and protein biosynthesis perturbations, DNA damage, heavy metals, and planar aromatic hydrocarbons. We found that each promoter or response element can be induced by one or more of four chemicals that were tested in the assay. These results have been interpreted in light of the current models of action for each compound. The responses of this assay system can distinguish among compounds that are closely related in their structure and have been shown previously to elicit similar biological activities in simple assay systems. We have designated this technique the CAT-Tox (L)iver assay. It measures a broad range of cellular stresses and toxicants at levels that were comparable to or below those of established methods. The induction profiles generated using the CAT-Tox (L) assay can help to elucidate the molecular mechanisms by which chemicals exert their actions on human cells. These profiles can be indicative of both toxic and nontoxic processes that are occurring in the cell. We propose that this cellular stress assay can serve as a screen for a variety of substances at the molecular level.

Morphogenetic reorganization of the brain during embryogenesis in the grasshopper

We have studied the morphogenetic reorganization that occurs in the grasshopper brain during embryogenesis. We find that morphogenetic movements occur at three organizational levels during brain development. First, the entire developing brain changes its orientation with respect to the segmental chain of ventral ganglia. A 90 degrees shift in the attitude of the brain neuraxis occurs during embryogenesis due to a gradual upward movement of the cerebral structures in the head. Second, the clusters of proliferating neuroblasts and progeny that generate the neuroarchitecture of the mature brain move relative to one another and to nonneural structures such as the stomodeum. This is especially pronounced for the pars intercerebralis and for the tritocerebrum, as shown by annulin and engrailed immunoreactivity. Third, individual neuroblasts within a given proliferative cluster undergo positional reorganization during embryogenesis. Identified neuroblasts of the tritocerebrum and the pars intercerebralis are displaced within the brain. We conclude that the transformation of the simple sheet-like structure of the early embryonic brain into the highly differentiated structure of the mature brain involves a series of morphogenetic movements that occur in virtually all parts of the brain.

Three-dimensional nuclear magnetic resonance microimaging of trabecular bone

The conventional approach to measuring structural parameters in trabecular bone rests on stereology from optical images, derived from sections of embedded bone. In order to provide data that are statistically representative of a sufficiently large volume, multiple sections need to be analyzed in each of the three orthogonal planes. In this work, an alternative technique is presented which is based on three-dimensional (3D) volumetric proton nuclear magnetic resonance (NMR) microimaging. The method presented provides from 9 x 9 x 4 mm3 volumes of defatted bone specimens in 15-20 minutes scan time at isotropic resolution corresponding to (78 microm)3 voxel size. Surface-rendered images of bovine and human trabecular bone are shown and an algorithm was developed and implemented for determining the orientation and magnitude of the principle axes of the mean intercept length tensor.

Chromosomal localization and molecular characterization of 53 cosmid-derived bovine microsatellites

Gene mapping in cattle has progressed rapidly in recent years largely owing to the introduction of powerful genetic markers, such as the microsatellites, and through advances in physical mapping techniques such as synteny mapping and fluorescence in situ hybridization (FISH). Microsatellite markers are often not physically mapped because they are generally isolated from small insert plasmid libraries, which makes their chromosomal localization inefficient. In this report we describe the FISH mapping of a large group of cosmid-derived bovine microsatellite markers, as our contribution to the European mapping initiative, BovMap. One objective of BovMap is to develop a set of anchored loci for the cattle genome map. Two cosmid libraries were screened with probes corresponding to the (AC)n microsatellite motif. Positive clones were mapped by FISH, and then a subset was further analyzed by sequencing the region flanking the microsatellite repeat. In total, 58 clones were hybridized with chromosomes and identified loci on 22 of the 31 different bovine chromosomes. Three clones contained satellite DNA. Two or more markers were placed on 12 chromosomes. Sequencing of the microsatellites and flanking regions was performed directly from 43 cosmids, as previously reported (Ferretti et al. Anim. Genet. 25, 209-214, 1994). Primers were developed for 39 markers and used to describe the polymorphism associated with the corresponding loci.

Clearing the cervical spine in obtunded patients: the use of dynamic fluoroscopy

OBJECTIVE

Obtunded patients (Glasgow Coma Scale score of < 13) with normal cervical roentgenograms remain in collars until they can be clinically evaluated. Cervical collars provide incomplete immobilization and have complications. Our hypothesis was that cervical spines could be evaluated in obtunded patients with normal cervical roentgenograms using dynamic fluoroscopy.

DESIGN

This study was a prospective clinical evaluation.

METHODS

Obtunded trauma patients with normal cervical roentgenograms underwent fluoroscopic examination of the cervical spine through a full range of motion.

RESULTS

Fluoroscopic evaluations were done in 116 patients. There were 113 true negative examinations. Two patients had facet fractures not diagnosed on cervical roentgenograms, and no instability on fluoroscopy. One patient had a positive exam, with 2 mm of subluxation. There were no neurologic complications. Decubiti were present in 44% and were more frequent when the collar was on > 5 days (p = 0.029).

CONCLUSIONS

Dynamic fluoroscopy can safely and effectively clear the cervical spine in obtunded patients. Earlier removal of the collar decreases decubiti.

The hyperthermic and neurotoxic effects of 'Ecstasy' (MDMA) and 3,4 methylenedioxyamphetamine (MDA) in the Dark Agouti (DA) rat, a model of the CYP2D6 poor metabolizer phenotype

1. The effect of administration of 3,4-methylenedioxymethamphetamine (MDMA or 'Ecstasy') and its N-demethylated product, 3,4-methylenedioxyamphetamine (MDA) on both rectal temperature and long term neurotoxic loss of cerebral 5-hydroxytryptamine (5-HT) has been studied in male and female Dark Agouti (DA) rats. The female metabolizes debrisoquine more slowly than the male and its use has been suggested as a model of the human debrisoquine 4-hydroxylase poor metabolizer phenotype. 2. A novel h.p.l.c. method was developed and used to measure plasma MDMA and MDA concentrations in the DA rats. 3. The hyperthermic response following MDMA was enhanced in female rats. Plasma MDMA concentrations were also 57% higher than in males 45 min post-injection, while plasma concentrations of MDA were 48% lower. 4. Plasma concentrations of MDMA and MDA in male rats were unaffected by pretreatment with proadifen (15 mg kg-1) or quinidine (60 mg kg-1), but the hyperthermic response to MDMA (10 mg kg-1, i.p.) was enhanced by quinidine pretreatment. 5. The hyperthermic response following MDA was greater in male DA rats, despite plasma drug concentrations being 40% higher in females 60 min after injection. 6. Seven days after a single dose of MDMA (10 mg kg-1, i.p.) there was a substantial loss in the concentration of 5-HT and 5-hydroxyindoleacetic acid (5-HIA) in cortex and hippocampus. [3H]-paroxetine binding was also decreased by 27% in the cortex, indicating that the amine loss reflected a neurodegenerative change. MDMA (5 mg kg-1, i.p.) was without effect on brain 5-HT content. content.7. A single dose of MDA (5 mg kg-1, i.p.) produced a major (approximately 40%) loss of 5-HT content of cortex and hippocampus 7 days later. The loss was similar in males and females.8 These data demonstrate that female DA rats are more susceptible to the acute hyperthermic effects ofMDMA, probably because of impaired N-demethylation and indicate that in human subjects acuteMDMA-induced toxicity may be exacerbated in poor metabolizer phenotypes. Low debrisoquine hydroxylase activity did not appear to impair the formation of a MDMA or MDA neurotoxic metabolite. Both severe acute hyperthermia and delayed neurotoxicity occurred following plasma levels of MDMA comparable to those reported in persons misusing the drug.

Probability of random sire exclusion using microsatellite markers for parentage verification

Many microsatellite sequences have been described in the bovine genome. Being highly polymorphic these have been suggested as markers for parentage verification and individual identification in cattle. We have evaluated the use of five highly polymorphic microsatellite markers for parentage verification in 14 breeds of cattle in the UK. Three of the microsatellite loci occur within introns in genes: BoLA DRB3, steroid 21-hydroxylase, and the beta subunit of the follicle-stimulating hormone. The other two are anonymous sites ETH131 and HEL6. Results were analysed by a statistical approach that takes in to account deviations from Hardy-Wienberg equilibrium and linkage disequilibrium for multiple loci. The method of determining the probability of random sire exclusion uses observed genotype frequencies instead of allele frequencies. Independently, the markers used have a probability of between 0.72 and 0.62 of identifying a parentage error, while used together the five markers give, on average across breeds, a probability of 0.99 of excluding an incorrect sire.

Use of dexamethasone for ureteric obstruction in advanced prostate cancer: percutaneous nephrostomies can be avoided

OBJECTIVE

To evaluate the effectiveness of dexamethasone in relieving bilateral lower ureteric obstruction in the acute phase of renal failure secondary to locally advanced prostate cancer.

PATIENTS AND METHODS

This study comprised 11 patients (median age 72 years, range 52-84) presenting with advanced prostate cancer, bilateral ureteric obstruction and gross renal failure. Their response to immediate administration of intravenous followed by oral dexamethasone for 4 weeks, in conjunction with definitive treatment and final outcome, was evaluated.

RESULTS

Renal function improved in 10 patients within 72 h. avoiding the need for insertion of percutaneous nephrostomies. However, four of 10 patients whose renal failure initially improved, failed to respond to definitive therapy, and died 3 to 4 weeks after cessation of the steroids.

CONCLUSION

When administered in the acute phase of renal failure from prostate cancer, dexamethasone may obviate the need for urinary diversion in patients with bilateral ureteric obstruction, particularly in men who will not respond favourably to available forms of therapy for advanced and aggressive disease.

Quantitative analysis of trabecular microstructure by 400 MHz nuclear magnetic resonance imaging

A new approach for the quantitative analysis of trabecular microstructure, based on high-field proton nuclear magnetic resonance (NMR) imaging, is presented. NMR is ideal because it provides high contrast between the marrow proton signal and the bone, which appears with background intensity. Images from 1 cm3 defatted specimens of trabecular bone, suspended in water doped with 1 mM Gd(DTPA) to shorten T1 to about 300 ms, can be obtained at a resolution on the order of 30-50 microns and slice thickness of 150 microns, in 10 minutes at 400 MHz proton frequency. Digital image processing algorithms were designed and evaluated for the measurement of bone area fraction, perimeter length, mean trabecular thickness, and separation. Bone area fraction derived from the NMR images was found to be in excellent agreement with bone volume fraction measured independently (slope = 0.96, r2 = 0.924, p < 0.0001). Errors in the mean trabecular thickness and separation were < 6%. The effects of finite imaging slice thickness and signal-to-noise ratio (SNR) were also evaluated. The data suggest a resolution of 50 x 50 x 200 microns 3 and an SNR on the order of 10 to provide safe margins for precise and accurate structural analysis by means of the algorithms presented in this paper. The method allows simultaneous measurement at multiple locations within the specimen volume without the need for physical sectioning.

Cortical cerebral blood flow cycling: anesthesia and arterial blood pressure

Cycling of various cerebral metabolic substances, arterial vascular diameter, and flow has been noted by many workers at a frequency near 0.1 Hz. Suspicion that this phenomenon is dependent on the type of anesthesia led us to investigate the occurrence of cerebral blood flow (CBF) cycling with different anesthetics. Fifteen Sprague-Dawley rats were anesthetized with either pentobarbital (n = 5, 40-50 mg/kg), alpha-chloralose (n = 5, 60 mg/kg), or halothane (n = 5, 1-0.5%). Body temperature was maintained at 37 degrees C. Femoral arterial and venous catheters were placed, and a tracheotomy was performed, permitting artificial ventilation with 30% O2-70% N2. A closed cranial window was formed over a 3-mm diameter craniotomy. Mean arterial pressure (MABP), arterial partial pressures of CO2 and O2 (PaCO2 and PaO2), and pH were controlled and stabilized at normal values. CBF was determined using laser Doppler flowmetry. To induce cycling, MABP was transiently and repeatedly lowered by exsanguination. Fast Fourier analysis of selected 64-s flow recordings (n = 38) was performed. CBF cycling was observed, independent of the type of anesthesia, in all animals. In 36 epochs, cycling was induced when MABP was reduced to a mean pressure of 65 +/- 1.5 mmHg. The mean frequency and amplitude were 0.094 +/- 0.003 Hz and 6.6 +/- 0.5%, respectively. Cycling occurred without blood withdrawal in two epochs. With the use of the blood-withdrawal epochs (n = 36), all three anesthetics shared a common linear slope between amplitude and blood pressure (P < 0.02) and blood pressure change (P < 0.01). Pentobarbital differed from alpha-chloralose and halothane in the relation between cycling frequency and blood pressure. Only pentobarbital exhibited correlation between frequency and blood pressure (P < 0.02) and blood pressure change (P < 0.001). The occurrence of these oscillations is not related to the type of anesthesia, and they usually occur at MABP values that are near or just above the lower limit of autoregulation. At this pressure level, CBF oscillations would suggest that vasoconstrictive and dilatory forces are no longer in balance, but alternatively vying for control.

The enzymatic basis for the rat liver 6-hydroxymelatonin sulfotransferase activity

Understanding 6-hydroxymelatonin (6HM) sulfation is deemed important to explaining normal and oncostatic actions of the pineal gland. Here we identify the enzymatic basis for this sulfation in rats. First, a quantitative assay was designed for measuring hepatic 6HM sulfotransferase (6HMST) activity. The assay was then used to identify a male dominant sexual dimorphism wherein liver from males contains double the 6HMST per g or per 100 g body weight seen in females. Examination of other rat tissues showed that most in vivo 6HM sulfation was likely to occur in liver. In addition, DEAE-Sephadex chromatography of liver cytosol indicated that 80-90% of the 6HMST activity in both sexes was due to an enzyme we named 6HMST II. A minor 6HM sulfotransferase (6HMST I) eluted from the columns prior to the main enzyme. 6HMST II, purified additionally, was shown to convert 6HM to a product that appeared to be 6HM sulfate (6-sulfa-toxymelatonin). The enzyme was inhibited by Na+, K+, Zn2+, and Cd2+. Its pH optimum was 7.80 +/- 0.30. Comparisons are made between 6HMST II, dopamine sulfotransferase II, and aryl sulfotransferase IV.

Axogenesis in the embryonic brain of the grasshopper Schistocerca gregaria: an identified cell analysis of early brain development

Axogenesis in the embryonic brain was studied at the single cell level in the grasshopper Schistocerca gregaria. A small set of individually identifiable pioneer neurons establishes a primary axon scaffold during early embryogenesis. At the beginning of scaffold formation, pioneering axons navigate along and between glial borders that surround clusters of proliferating neuroblasts. In each brain hemisphere, an axonal outgrowth cascade involving a series of pioneer neurons establishes a pathway from the optic ganglia to the brain midline. At the midline the primary preoral commissural interconnection in the embryonic brain is pioneered by a pair of midline-derived pioneer neurons. A second preoral commissural connection is pioneered by two pairs of pars intercerebralis pioneer neurons. Descending tracts are pioneered by the progeny of identified neuroblasts in the pars intercerebralis, deutocerebrum and tritocerebrum; the postoral tritocerebral commissure is pioneered by a pair of tritocerebral neurons. All of the pioneering brain neurons express the cell adhesion molecule fasciclin I during initial axon outgrowth and fasciculation. Once established, the primary axon scaffold of the brain is used for fasciculation by subsequently differentiating neurons and, by the 40% stage of embryogenesis, axonal projections that characterize the mature brain become evident. The single cell analysis of grasshopper brain development presented here sets the stage for manipulative cell biological experiments and provides the basis for comparative molecular genetic studies of embryonic brain development in Drosophila.

Transient blood-brain barrier passage of polar compounds at low pH

The brain uptake index (BUI) of polar 14C-labeled test compounds with molecular weights (MWs) of 79-70,000 was examined using the single-pass carotid injection technique in pentobarbital-anesthetized rats. Compounds were injected in 40 mM malonate, pH 2.5, and 10 mM N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid, pH 7.4. BUI is defined as (14C-labeled test compound/[3H]H2O in brain)/(14C-labeled test compound/[3H]H2O in injectate) x 100 at a 5-s decapitation time. Increased BUIs of compounds in pH 2.5 buffer were MW dependent with a threshold < 5,000. BUI, extraction, and permeability-surface area product (PS) were significantly greater at pH 2.5 compared with pH 7.4 (P < 0.05). Washouts of [14C]butanol and [3H]H2O at pH 2.5 and pH 7.4 were calculated. Cerebral blood flow and PS increased at low pH. Other buffers, oxalate, glycine, and lactate were used at low pH and also increased BUIs. The duration of the blood-brain barrier (BBB) opening at pH 2.5 was 60 s as estimated by penetrance of the normally excluded dye fluorescein. A plot of BUI or PS at pH 2.5 vs. (MW)1/2 suggests that transient BBB tight junction opening contributed to the passage of polar compounds at low pH.

Distribution in the Western United States on Alfalfa and Cultivar Reaction to Mixed Populations of Ditylenchus dipsaci and Aphelenchoides ritzemabosi

Ditylenchus dipsaci and Aphelenchoides ritzemabosi were extracted from 29 of 40 plant samples (72.5%) collected from Arizona, California, Colorado, Idaho, Montana, Oregon, South Dakota, Utah, Washington, and Wyoming. Percentages of A. ritzemabosi in tissue of the 29 samples ranged from 1.77 to 67.82%. Only Ditylenchus dipsaci was recovered from the remaining 11 samples. All of the 16 fields sampled in Wyoming contained both nematodes. Percentages of A. ritzemabosi in the Wyoming samples ranged from 0.7-30.0%, with an overall mean of 10.3%. Individual plants collected from a field in Big Horn, Wyoming, all contained both nematodes. Percentages of A. ritzemabosi in tissue ranged from 5-70%. Alfalfa stem nematode symptomatic plants in 17 of 18 alfalfa cultivars collected from a screening nursery in California contained both nematodes, of which 10-94% were A. ritzemabosi. Only one cultivar had D. dipsaci only, and no entries had A. ritzemabosi only. Under environmentally controlled conditions, A. ritzemabosi reproduced in all nine alfalfa cultivars tested at 6 weeks of age with a mean reproductive factor (final population/initial population) of 4.1. There were more (P </= 0.05) A. ritzemabosi in stem and bud tissue of the susceptible cultivars at harvest than in the resistant cultivars with combined cultivar means of 238, 42, 78, and 4 A. ritzemabosi/g tissue for the susceptible, moderately resistant, resistant, and highly resistant cultivars, respectively. Percentage A. ritzemabosi in tissues decreased over time in seedlings but increased in older plants.

Radioimmunoassay for the determination of alosetron in human urine and saliva

The development of a radioimmunoassay (RIA) for the sub-ng ml-1 determination of alosetron, a potent and selective 5HT3 receptor antagonist, in human urine and saliva is described. The antiserum was raised in Soay sheep following primary and booster immunizations with an immunogen prepared by conjugating alosetron-p-azobenzoic acid to bovine serum albumin (BSA). The radioligand consisted of alosetron specifically 125-iodinated on the 2-position of the imidazole group. The mean (+/- standard deviation) theoretical sensitivity (minimum detectable dose corresponding to the imprecision of the zero standard) of the RIA is 3.2 +/- 2.6 pg ml-1 (n = 12) of alosetron in assay diluent (0.1% m/v gelatine-0.05% m/v sodium azide in 0.1 mol l-1 phosphate buffer solution, pH 7.4). The working calibration range using 0.1 ml samples of saliva and 20-fold diluted urine is 0.10-6.40 ng ml-1 of alosetron. Urine samples were diluted prior to assay to overcome adverse matrix effects; consequently, the lower limit of quantification for undiluted urine is 2.0 ng ml-1 of alosetron. Inter- and intra-assay bias and imprecision over the working calibration range were generally < +/- 12% and < 13%, respectively, except at the 0.10 ng ml-1 alosetron level, where the corresponding values were < +/- 17.3% and < 20.2%. The antiserum was free from adverse cross-reactivity with either a synthetic precursor of alosetron or with four major metabolites of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute intraoperative arterial elongation: histologic, morphologic, and vascular reactivity studies

This study focuses on the histomorphologic damage produced by an acute elongation process, as well as on quantifying the alterations in arterial contractility following the application of this technique. Light microscopy and scanning electron microscopy studies were prepared from expanded and non-expanded pig superficial femoral arteries (SFA) harvested immediately following expansion, and again at 24- and 72-hr intervals. Histologically, the expanded vessels showed minor, patchy, endothelial slough, but not fragmentation of the internal or external elastic lamina. At 24 hr, the endothelium showed reactive changes, but no evidence of smooth-muscle necrosis of the tunica media was observed. At 72 hr, healing of the endothelium was evident by SEM. Similar specimens, also from the SFA, were harvested and placed in organ chambers immediately following expansion and 24 hr later, to measure contractility when exposed to alpha-adrenergic agonists. The vessels were exposed to the contractile agonists, phenylephrine and 5-hydroxytryptamine, which evoked similar concentration-dependent increases in tension in both the expanded group and the controls. From these observations, the authors conclude that acute intraoperative elongation of arteries results in only minor endothelial damage, without affecting the inherent contractility of the vessel wall.

Polymorphism analysis of the prion gene in BSE-affected and unaffected cattle

Polymerase chain reaction (PCR) primers designed to amplify the octapeptide repeat region of the bovine prion gene were used to test the association of genotypes with bovine spongiform encephalitis (BSE) in 56 BSE-affected and 177 unaffected animals. Three alleles (A,B,C) were detected as single-strand conformation polymorphisms (SSCPs) and two alleles (1,2--representing six or five copies of the octapeptide repeat respectively) were detected as amplified double-strand fragment length polymorphisms (AMFLPs). Observed genotypes of SSCPs and AMFLPs were analysed by chi-square. The SSCP genotypes of nuclear family members of animals with BSE and BSE-affected animals were different (P < 0.001, P < 0.01) from unrelated animals of the same breed without BSE. No genotypic differences were found between the BSE-affected animals and their relatives (P > 0.469). No AMFLP genotypic differences were detected between BSE-affected animals, their relatives, unrelated animals of the same breed or animals of different breeds (P > 0.05). These data suggest that BSE-affected animals and their relatives are more likely to have the AA SSCP genotype than unrelated animals of the same breed or animals of different breeds.

Cerebellar lesions alter autonomic responses to transient isovolaemic changes in arterial pressure in anaesthetized cats

In previous studies, bilateral lesions of the rostral fastigial nucleus (rFN) of the cerebellum impaired recovery of mean arterial pressure (MAP) after many forms of hypotension. This study examined effects of cerebellar lesions on baroreflex responses during transient, isovolaemic, non-orthostatic changes in MAP in anaesthetized cats. Bilateral rFN lesions did not alter the rate or extent of fall in MAP induced by nitroprusside, but reduced by 39% the reflex increase in heart rate per unit decrease in pressure (delta HR/delta MAP). Femoral artery resistance remained below control levels. Lesions prolonged the time for 50% MAP recovery after nitroprusside by 93%. During phenylephrine-induced MAP increases, bilateral rFN lesions augmented reflex delta HR/delta MAP by 68%. In intact cats, the reflex decrease in HR after phenylephrine was blocked by electrical stimulation of the rFN, but appeared immediately after stimulation was stopped. Stimulation alone increased both MAP and HR. Propranolol failed to block either the increased HR or the suppression of reflex cardiodeceleration induced by rFN stimulation. Decreases in resting HR after rFN lesions may reflect removal of tonic cerebellar inhibition of cardiac parasympathetic tone. Thus, the cerebellum can influence autonomic output and modify baroreflex sensitivity by augmenting cardiovascular responses mediated by the sympathetic nervous system and inhibiting those mediated by the parasympathetic nervous system.

A surgical approach to the sublingual salivary gland

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