Consistency and reproducibility of AmpliType PM results between seven laboratories: field trial results

The AmpliType PM Field Trial was designed to assess the ability of forensic laboratories to obtain the correct results from samples commonly encountered in forensic casework. The seven forensic laboratory participants of the AmpliType PM Field Trial each performed four studies. Samples were analyzed using components of the AmpliType PM PCR Amplification and Typing Kit. Laboratories were also provided with DNA probe strips to type the DQA1 locus. Of the 381 PM and 325 DQA1 DNA probe strip results obtained from DNA-containing and non-DNA-containing samples, 98.2% and 95.7% showed the correct result for PM and DQA1 types, respectively. No samples were typed incorrectly. The remaining small percentage of samples were either uninterpretable due to the presence of a mixture, or no result was obtained due to insufficient DNA. The Field Trial demonstrated that laboratories can easily implement the AmpliType PM system to analyze DNA-containing samples and controls successfully for forensic casework applications.

Interaction between adriamycin cytotoxicity and hyperthermia: growth-phase-dependent thermal sensitization

Thermal sensitization of adriamycin cytotoxicity was studied in vitro and in vivo using tumour cells originated from a spontaneous mouse fibrosarcoma, FSa-II. The adriamycin dose-cell survival curve for exponentially growing cells was biphasic with the initial sensitive portion followed by a resistant tail. The survival curves determined in vitro as a function of treatment time at various temperatures were also biphasic. With increasing temperatures the initial portion became steeper and the resistant fraction decreased. At a temperature of 43 degrees C, which gives lethal damage to cells by itself, the cell survival decreased rapidly during the initial 30 min of treatment and became relatively constant for subsequent treatment times up to 180 min. The tumour response determined by the median tumour growth time for one-half of treated tumours to reach 1000 mm3 from the treatment day (35 mm3) indicated that the tumour response to adriamycin was independent of temperature. Hyperthermia at 43.5 degrees C for 60 min prolonged the tumour growth time without showing chemosensitization. The maximum drug dose used was 12 mg/kg that is < LD10 or the drug dose that kills animals with < 10% probability. The dose-response curves (tumour growth versus drug dose) showed identical slopes at room temperature, 41.5 and 43.5 degrees C. Further studies were conducted in vitro. Plateau phase cells were treated with graded adriamycin doses for 60 min at 37 degrees C, or with a constant adriamycin dose of 0.25 microgram/ml for various times at 37 or 43 degrees C. The dose-cell survival curves for both exponential and plateau phase cells were biphasic, but the plateau phase cells were more resistant to adriamycin at 37 degrees C than the exponential phase cells. The survival curve for plateau phase cells, determined as a function of treatment time, showed an initial shoulder followed by an exponential portion. Compared with the heat survival curve at 43 degrees C, the survival curve for the drug treatment at 43 degrees C was identical to that for the heat alone treatment for the first 60 min and then became steeper than the heat alone survival curve. These results suggest that adriamycin cytotoxicity may be enhanced at elevated temperatures only when tumours are treated for a prolonged time or possibly with a large drug dose.

The distribution of inflammatory demyelinated lesions in the central nervous system of rats with antibody-augmented demyelinating experimental allergic encephalomyelitis

Experimental allergic encephalomyelitis (EAE) has long been studied as an animal model of the human demyelinating disease Multiple Sclerosis. However, EAE induced in the Lewis rat by injection of myelin basic protein (MBP), or MBP-specific T-lymphocytes, is primarily an inflammatory condition of the central nervous system (CNS) with little or no demyelination. In EAE models in which demyelination does result, it is either not very widespread or is unpredictable in its degree and location. In this study we have produced antibody-augmented demyelinating EAE (ADEAE) in the Lewis rat by injection of activated MBP-specific T-lymphoblasts, followed by injection 4 days later of a monoclonal antibody against myelin/oligodendrocyte glycoprotein, an extrinsic protein of myelin. We have documented the extent and location of inflammatory cell infiltrates and demyelination throughout the CNS using histochemistry, immunofluorescence, and image analysis. Perivascular inflammatory infiltrates were seen in the deep cerebellar white matter and in the folia. Perivascular, periventricular, and subpial inflammation was widespread throughout the pons/medulla and at all levels of the spinal cord. Very little inflammation was apparent in the forebrain. MBP immunofluorescence demonstrated extensive areas of periventricular demyelination in the forebrain around the third ventricle. Both periventricular and perivascular lesions were commonly observed in the cerebellum and pons/medulla. The extent of demyelination in the spinal cord increased caudally with large confluent areas of subpial demyelination seen throughout the lumbar cord. The extensive and reproducible distribution of inflammatory demyelinating lesions in ADEAE provide the possibility to select areas of the CNS for more detailed analysis of the cellular changes that accompany demyelination and remyelination.

Transdermal fentanyl disposition in elderly subjects

The pharmacokinetic characteristics of a 20-cm2 fentanyl 24-hour transdermal patch were compared between 10 healthy elderly subjects 67-87 years and 6 young subjects 19-27 years. All 10 elderly subjects required patch removal prior to 24 h due to adverse effects versus none of the young subjects. The mean patch duration (PD) in elderly subjects was 11.7 +/- 4.9 h, yielding a mean area under the curve from 0 to 60 h (AUC0-60) of 20.4 +/- 10.3 ng h/ml versus a mean AUC0-60 of 21.0 +/- 10.4 ng h/ml in young subjects. Correcting AUC0-60 for PD (AUC0-60/PD) gave a mean value of 2.05 +/- 1.10 ng/ml for elderly subjects, which was significantly greater than the AUC0-60/PD of 0.88 +/- 0.44 ng/ml in young subjects (p = 0.034, Student's t test). The higher serum concentrations reflect increased absorption and/or decreased clearance in the elderly.

Retarded development of neurons and oligodendroglia in rat forebrain produced by hyperphenylalaninemia results in permanent deficits in myelin despite long recovery periods

The severe hypomyelination seen in the CNS of untreated phenylketonuria (PKU) patients has been suggested to be the result of a defect in the process of myelination itself. Using chronic hyperphenylalaninemia (HPA) in rats as a model of PKU we have previously shown, by immunohistochemistry, that axonal maturation as well as myelination was severely retarded. In the present study we have used image analysis techniques to quantitate changes in myelin basic protein (MBP) and 200-kDa neurofilament protein (NF-H) immunostaining in the corpus callosum and cerebral cortical grey matter of HPA rats. No difference in the density of MBP+ myelin was observed in the corpus callosum after 24 days HPA treatment although the width of the tract was much reduced. In contrast there was a deficit in NF-H immunostaining. Large deficits in both myelin and axonal maturity were seen in the cortical grey matter. Following a 6-week recovery period, despite recovery in the corpus callosum, large deficits in both MBP and NF-H were still seen in all cortical layers. Deficits in NF-H immunostaining were two to three times greater than those for MBP. On increasing the recovery period to 18 weeks significant deficits in myelin remained in layers I-III of the cortical grey matter whereas NF-H immunostaining had returned to normal levels in all layers. Our data suggest a primary effect of HPA on neuronal development, in particular axonal maturation, with a secondary hypomyelination and show that permanent deficits in myelinated axons in outer cortical layers can result when myelination is severely inhibited during a critical developmental period.

Cellular reaction to an acute demyelinating/remyelinating lesion of the rat brain stem: localisation of GD3 ganglioside immunoreactivity

We describe a simple and reproducible acute demyelinating lesion of the rat brain stem induced by injection of ethidium bromide into the cisterna magna of young adult rats. Using immunofluorescence with a panel of antibodies to cell-specific antigens we have studied the changes in cell populations that occur at various stages during lesion progression and repair. In particular we localized the expression of ganglioside GD3 immunoreactivity, a marker for oligodendroglial progenitors in developing brain. Both astroglia (GFAP+) and oligodendroglia (CNP+) were destroyed during the early response to the ethidium bromide although axons were spared. Splitting of myelin lamellae occurred as early as 4 days post-injection (DPI), with extensive demyelination of the inferior cerebellar peduncle following by 6 DPI. Large numbers of ED1+ and OX-42+ macrophages were present in the lesion site at this stage. Astrogliosis occurred around the perimeter of the lesions. Two populations of GD3+ cells appeared within and around the lesion sites during the demyelination. One population was identified by the phenotype GD3+ ED1+ and thus probably belonged to the macrophage/microglial lineage. In these cells both antigens appeared cytoplasmic. The second population of GD3+ cells exhibited cell membrane GD3 immunoreactivity but did not express the ED1 antigen. These cells are suggested to be oligodendroglial progenitors generated in response to the demyelination. No such cells were seen in control tissue. GD3+ cells were present within the lesion sites from 6 DPI until 10-12 DPI. Following the clearance of myelin debris from the lesions, remyelination was a relatively rapid event with thin MBP+ myelin sheaths first seen at 11-12 DPI. Remyelination, which was extensive by 25 DPI, was predominantly oligodendroglial in origin (MBP+P0- myelin) with only small pockets of peripheral myelin (MBP+P0+ myelin) observed. The present study, in addition to identifying putative glial progenitors within a demyelinated lesion, also demonstrates the difficulties in unambiguously identifying such cells in the normal and damaged adult CNS.

Neuron-oligodendroglial interactions during central nervous system development

It is well established that a variety of growth factors influence the differentiation of oligodendroglial lineage cells in culture, although little information is available concerning the role and source of these factors in vivo. Developing oligodendroglia are almost constantly in a neuronal environment and would be expected to respond to a variety of signals from neurons that affect their survival, migration, division, maturation and myelin production. However, very little is known about the specific interactions that occur between these two cell types. Here we review the experimental evidence for the influence of neurons on oligodendroglial differentiation, including studies on the effects of both soluble factors and contact dependent events. We also propose a scheme for the control of myelinogenesis via both internal and external signals.

Distribution of glial fibrillary acidic protein and glutamine synthetase in human cerebral cortical astrocytes--a light and electron microscopic study

Human cerebral cortex was studied immunocytochemically by light and electron microscopy using antibodies against glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS). Glial fibrillary acidic protein-positive cells and processes were present in both cortex and white matter, but in contrast glutamine synthetase-positive cells and processes were present only in cortex. Cell bodies which contained glutamine synthetase had typical ultrastructural features of protoplasmic astrocytes. Glutamine synthetase-positive processes were often present near asymmetrical synapses in the neuropil. These processes often contained mitochondria, but not glial filaments, and were different from unlabelled astrocytic processes, which seldom contained mitochondria, but had large numbers of glial filaments. Glutamine synthetase immunoreactivity therefore affords a means of distinguishing between these two types of astrocytic processes in the human cerebral cortex.

Rat cerebral cortical neurons in primary culture release a mitogen specific for early (GD3+/04-) oligodendroglial progenitors

The development of cells of the oligodendroglial lineage, from immature progenitor to myelinating cells, occurs largely in a neuronal environment, yet little is known about specific interactions between these 2 cell types. We have tested the effects of medium conditioned by cultures of rat cerebral cortical neurons (CCM), cerebellar granule interneurons (GCM), and a dorsal root ganglion derived cell line (NDCM) on cells of the oligodendroglial lineage in culture. Different stages of the lineage were defined using the cell surface antigens GD3, 04, and GalC. CCM and NDCM were mitogenic for the early GD3+/04- oligodendroglial progenitor, whereas GCM was mitogenic for the later GD3+/04+ stage. Neutralising antibodies to PDGF and bFGF were able to eliminate the mitogenic activity of NDCM and GCM, respectively, but did not abolish the mitogenic effect of CCM. We have demonstrated that neurons in primary culture from distinct CNS regions exert different influences on cells of the oligodendroglial lineage, and specifically that cortical neurons release an unknown mitogen for GD3+/04- oligodendroglial progenitors.

Synergism between alkylating agent and cis-platin with moderate local hyperthermia: the effect of multidrug chemotherapy in an animal system

The combined effect of multidrug chemotherapy given in combination with hyperthermia was investigated using early-generation isotransplants of a spontaneous fibrosarcoma, FSa-II in C3Hf/Sed mice. Combinations of various types of chemotherapeutic agents, including alkylating agents, cyclophosphamide (CY) and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU); antibiotics, bleomycin (BLM) and mitomycin C (MMC); an antimetabolite, 5-fluorouracil (5FU); and a platinum complex, cis-diamminedichloroplatinum(II) (cDDP), were examined using the tumour growth (TG) time assay. Simultaneously, the effect of glucose on the response to thermochemotherapy was investigated. Graded doses of the multidrugs were given i.p. immediately before hyperthermia with or without a glucose dose of 5 g/kg given i.p. 60 min before hyperthermia. Hyperthermia was given by immersing the tumour-bearing murine feet into a water bath set at 41.5 +/- 0.05 degrees C for 60 min. Dose-response curves were obtained between the TG time and drug dose. The thermal enhancement ratio (TER) was expressed as a ratio of the slope of the dose-response curve obtained at 41.5 degrees C to that obtained at room temperature. To evaluate normal tissue damage, the number of white blood cells (WBC) was counted from a day before treatment to the 21st day after treatment. A substantial thermal enhancement of the anti-tumour effect was observed in all five multidrug regimens tested. Glucose administered prior to thermochemotherapy further enhanced the antitumour effect. The TER was largest for the combination of CY+cDDP (TER was 5 without glucose). The second largest TER was obtained for a combination of CY+cDDP+MMC (TER was 4.1 without glucose and 6.5 with glucose). The antitumour effects of these two combinations were synergistic at a test elevated temperature only. No synergistic effect was found at room temperature for any of the drug combinations tested. The smaller TERs were observed in the treatment regimens that included 5FU. In general, a decrease in the number of WBC following multidrug chemotherapy was slightly less than that following the individual drugs.

Metabolic engineering of Candida tropicalis for the production of long-chain dicarboxylic acids

We have engineered an industrial strain of the yeast, Candida tropicalis, for the efficient production of long-chain dicarboxylic acids, which are important raw materials for the chemical industry. By sequential disruption of the four genes encoding both isozymes of the acyl-CoA oxidase which catalyzes the first reaction in the beta-oxidation pathway, alkane and fatty acid substrates have been successfully redirected to the omega-oxidation pathway. Consequently, the conversion efficiency and chemical selectivity of their terminal oxidation to the corresponding dicarboxylic acids has been improved to 100 percent. The specific productivity of the bioconversion has been increased further by amplification of the cytochrome P450 monooxygenase and NADPH-cytochrome reductase genes encoding the rate-limiting omega-hydroxylase in the omega-oxidation pathway. The amplified strains demonstrated increased omega-hydroxylase activity and a 30% increase in productivity compared to the beta-oxidation-blocked strain in fermentations. The bioconversion is effective for the selective terminal oxidation of both saturated and unsaturated linear aliphatic substrates with chain-lengths ranging from 12 carbons to 22 carbons and also avoids the undesirable chain modifications associated with passage through the beta-oxidation pathway, such as unsaturation, hydroxylation, or chain shortening. It is now possible to efficiently produce a wide range of previously unavailable saturated and unsaturated dicarboxylic acids with a high degree of purity.

The effect of dietary fruits and vegetables on urinary galactitol excretion in galactose-1-phosphate uridyltransferase deficiency

Even on a lactose-restricted diet, urinary galactitol excretion and erythrocyte galactose-1-phosphate levels are persistently elevated in patients with galactose-1-phosphate uridyltransferase deficiency. In order to determine the contribution of galactose in dietary fruits and vegetables to this phenomenon, (1) the content of galactose in a lactose-free diet was directly measured when a galactosaemic patient's diet was specifically enriched in those fruits and vegetables which contain relatively large amounts of free galactose and (2) galactitol excretion was determined during ingestion of this diet for 3 weeks and while on a synthetic diet for 1 week that provided < 8 mg galactose/day. For comparison the effect of a 3-week supplementation of 200 mg galactose/day was determined. The measured intake in total foodstuffs matched the theoretical content of galactose in the patient's diet based on amounts in fruits and vegetables alone, thus supporting the concept that fruits and vegetables are primarily responsible for galactose intake in a lactose-free diet. All of the dietary manipulations, however, had relatively little effect on metabolite levels, suggesting that endogenous galactose production is primarily responsible for the elevated levels of galactose metabolites routinely detected in patients on lactose-restricted diets.

Secondary processing of chondrules and refractory inclusions (CAIs) by gasdynamic heating

A theoretical model of aerodynamic heating of a meteoric particle upon entry into a parent body atmosphere is presented. The model includes the effects of melting, vaporization, and heat conduction into the particle interior. Properties of chondrule rims are interpreted in the context of the model. We conclude that the formation of true melt rims by atmospheric entry requires that a low-melting-temperature component be fractionated in the outer part of the chondrule prior to rim formation, and that the range of thermal alteration effects observed in UOC chondrites reflects the variety of encounter conditions and chondrite types. Further tests of the model are suggested.

A rapid chemiluminescent method for quantitation of human DNA

A sensitive and simple method for the quantitation of human DNA is described. This method is based on probe hybridization to a human alpha satellite locus, D17Z1. The biotinylated probe is hybridized to sample DNA immobilized on nylon membrane. The subsequent binding of streptavidin-horseradish peroxidase to the bound probe allows for chemiluminescent detection using a luminol-based reagent and X-ray film. Less than 150 pg of human DNA can easily be detected with a 15 minute exposure. The entire procedure can be performed in 1.5 hours. Microgram quantities of nonhuman DNA have been tested and the results indicate very high specificity for human DNA. The data on film can be scanned into a computer and a commercially available program can be used to create a standard curve where DNA quantity is plotted against the mean density of each slot blot signal. The methods described can also be applied to the very sensitive determination of quantity and quality (size) of DNA on Southern blots. The high sensitivity of this quantitation method requires the consumption of only a fraction of sample for analysis. Determination of DNA quantity is necessary for RFLP and many PCR-based tests where optimal results are obtained only with a relatively narrow range of DNA quantities. The specificity of this quantitation method for human DNA will be useful for the analysis of samples that may also contain bacterial or other non-human DNA, for example forensic evidence samples, ancient DNA samples, or clinical samples.

Dose response, coasting, and differential fiber vulnerability in human toxic neuropathy: a prospective study of pyridoxine neurotoxicity

We administered either 1 or 3 g/d of pyridoxine (vitamin B6) to five healthy volunteers and repeatedly followed serum pyridoxal phosphate levels, clinical symptoms and signs, quantitative sensory thresholds (QSTs), and sural nerve electrophysiology. Pyridoxine was discontinued at the first sign of either clinical or laboratory abnormality. In all subjects, sensory symptoms and QST abnormalities occurred concurrently. Subjects receiving higher doses became symptomatic earlier than low-dose subjects. Elevation of thermal QSTs preceded or exceeded that for vibration in the three low-dose subjects; vibration and thermal QST became abnormal simultaneously in the higher-dose subjects. A reduction in the amplitude of the sural sensory potential lagged behind QST changes in two of three subjects. Symptoms continued to progress ("coasting") for 2 to 3 weeks despite stopping pyridoxine administration and the return of serum pyridoxal phosphate levels to normal. This study suggests that (1) there is a clear dose-percent relationship for pyridoxine-induced neuropathy, (2) QST is a sensitive measurement for detecting early peripheral neuropathy; QST abnormalities may precede changes in nerve conduction studies, (3) coasting appears unrelated to persistently elevated blood levels of the toxin, and (4) a dose-dependent vulnerability may exist among nerve fibers of different caliber when exposed to an axonal toxin, such as pyridoxine.

Parameters affecting transcription termination by Escherichia coli RNA. II. Construction and analysis of hybrid terminators

Rho-independent terminators are characterized by two major functional regions, one upstream from the termination site having a sequence capable of forming an RNA hairpin in the nascent transcript, the second extending, from the base of this hairpin, seven to nine nucleotides along the transcript to the actual sites of termination (3'-tail region). This latter region of the transcript is often rich in uridine residues. Both regions are postulated to play central roles in the termination process. We have constructed a series of hybrid rho-independent, transcription terminators in which sequences upstream and downstream from the RNA hairpin for the Escherichia coli trp attenuator (trpatt+) are interchanged with sequences from trpatt mutant (1419) or from the phage T7 early terminator (T7Te). Similar hybrids have been constructed for T7Te, replacing flanking sequences with trpatt regions. The effects of such changes on transcription termination have been tested in vitro with purified E. coli RNA polymerase to determine the intrinsic termination efficiency (%T) of each hybrid terminator. Both the trpatt+ terminator and T7Te are highly efficient rho-independent terminators in vitro. However, replacement of trpatt+ sequences upstream and downstream from the RNA-terminator hairpin with the comparable T7Te sequences reduces %T dramatically, suggesting that the RNA-terminator hairpin does not function independently from its flanking regions. Regions downstream from the actual termination/release site are shown to be of considerable importance in determining %T for terminators bearing the T7Te or trpatt1419 3'-tail region, but have little effect on terminators with the trpatt+ 3'-tail region. For terminators bearing the T7Te or trpatt1419 3'-tail region that are inefficient, efficient termination is restored by elevated concentrations of KCl in the reaction. The results do not fit well with models for termination in which %T is determined by a two-step process in which the terminator-RNA hairpin, and a seven to 12 base-pair DNA-RNA hybrid structure rich in uridine residues, act independently to cause the polymerase to pause, and to release the transcript, respectively. DNA sequences both upstream and downstream from these regions, as well as DNA sequences downstream from the transcript termination site, can significantly affect the termination process. Conversely, terminators lacking a 3'-tail region rich in uridine residues can be highly efficient, but only when joined with appropriate sequence immediately downstream from the termination site. This suggests that the 3'-tail region acts in some manner other than the formation of an unstable DNA-RNA hybrid that facilitates termination.

Disturbed myelinogenesis and recovery in hyperphenylalaninemia in rats: an immunohistochemical study

Chronic hyperphenylalaninemia (HPA) in rats has been used as an experimental model of the human inborn error of metabolism phenylketonuria (PKU). Impaired brain development in PKU and HPA is reflected in reduced myelin formation. We have used immunohistochemistry, with antibodies to cell-specific antigenic markers, to investigate the cellular basis of the hypomyelination in the corpus callosum and cerebral cortex of rats made hyperphenylalaninemic from Postnatal Days 3-17. The rats were then allowed to recover until Day 59. No effects were seen on the number and differentiation pattern of ganglioside GD3-expressing glial progenitors. Myelin basic protein and 2'3'-cyclic nucleotide 3'-phosphohydrolase (CNP) immunostaining demonstrated a reduction in myelin formation in the corpus callosum and subcortical white matter at 12 and 17 days postnatal. However, numbers of CNP+ oligodendrocytes appeared normal throughout development. No reactive astrogliosis was seen at any stage. The intensity of axonal neurofilament immunostaining was reduced in the corpus callosum at 17 days. In layers II and III of the cortical gray matter there was an increase in the cell packing density and a concomitant decrease in cell body size. Myelination in the corpus callosum was rapid during the recovery period with no difference noted at Day 59. Axonal neurofilament staining also returned to normal in the corpus callosum. However, recovery became increasingly incomplete away from the corpus callosum into the cortical gray matter. Our data suggest a primary effect of HPA on axonal maturation with hypomyelination consequential upon this.

Parameters affecting transcription termination by Escherichia coli RNA polymerase

Escherichia coli RNA polymerase can terminate transcription efficiently at rho-independent terminators in a purified transcription system in the absence of accessory factors. This process of "intrinsic termination" involves direct recognition of the terminator by the core RNA polymerase, and provides an important model system for the study of the molecular interactions involved in the switch between elongation and termination. We have analyzed the intrinsic termination efficiency (%T) of 13 rho-independent terminators, under a variety of in vitro reaction conditions. Although all of these sites share the general sequence features of typical rho-independent terminators, we find a wide range of %T (2% to 90%) for the different sites under our standard transcription conditions. While %T for a particular site is characteristic of that site, the efficiency can be altered considerably by the nature and concentration of salts in the reaction, by alteration of the concentrations of the nucleoside triphosphate substrates, or by transcription from supercoiled rather than linear templates. Surprisingly, different conditions can alter %T to a different extent for different terminators. For neutral salts such as potassium chloride or potassium glutamate, changes in the range from 0.1 to 1 M affect %T for different terminators in a distinct manner, depending on the terminator and the anion involved. At some sites, %T is greatly increased by Cl- concentrations up to 1 M, while at other sites %T is reduced or unaffected by these conditions. At some sites K+ concentrations up to 1 M give a modest increase in %T, while at other sites %T is slightly reduced under the same conditions. Thus the actual values of %T, as well as the order of terminator sites ranked according to %T, can be altered greatly according to the choice of reaction conditions. Reduction of the Mg2+ concentration below 1 mM has a dramatic and quite different effect, enhancing termination to approximately 100% for all terminators tested. Transcription of supercoiled DNA templates gives somewhat reduced %T as compared with linear DNA templates. However, the effect is no greater than twofold. Our results are not consistent with those expected for models in which %T is determined by the differential stability of DNA, RNA and hybrid duplex structures at the melted region in the transcription complex. Thus, the Cl anion does not affect the stability of nucleic acid duplexes even at 1 M concentrations, but can enhance termination tenfold. Also, the alterations of monovalent cation concentration that affect %T are not expected to have a differential effect on Tm for DNA, RNA and hybrid duplexes.(ABSTRACT TRUNCATED AT 400 WORDS)

Cardiac output measurement in critical care patients: Thoracic Electrical Bioimpedance versus thermodilution

Thoracic Electrical Bioimpedance (TEB) is a method for measuring cardiac performance which is noninvasive, continuous, has minimal technical requirements, and no patient risk. We used a commercially available TEB device to measure cardiac output in patients with thermodilution catheters in place. We compared the cardiac output measurements for the two modalities. We also compared the average hospital cost for initial cardiac assessment using the two techniques. The mean difference between the two cardiac output measurements was small (0.23 +/- 0.56) and not affected by the magnitude of the cardiac output readings. There was a strong correlation between COTD and COTEB (r = 0.91) and the regression slope was 0.91 with a Y intercept of 0.76. Cost analysis demonstrated that the use of TEB was approximately $600 less than thermodilution. Thoracic electrical bioimpedance measurement of cardiac output may offer a valuable alternative to the invasive measurement of the thermodilution catheter.

Proliferation and differentiation potential of rat forebrain oligodendroglial progenitors both in vitro and in vivo

We have followed the development of the O-2A progenitor cell from the neonatal rat forebrain, both in dissociated cell culture and in cryostat sections, using immunocytochemical techniques employing a panel of antibodies that recognise the cells at different stages of their development. This included the monoclonal antibody LB1, which binds to the surface ganglioside GD3 expressed on O-2A progenitor cells. In secondary cultures enriched for O-2A progenitors maintained in a serum-free chemically defined medium, a large proportion of the cells are primed to differentiate into oligodendroglia and go on to express the oligodendroglial specific surface glycolipid galactocerebroside (GC) and then the myelin proteins CNP and MBP. However, a significant proportion of immature bipolar GD3+ cells remained after 6 days in secondary culture. It appears that not all the O-2A progenitors in our cultures differentiate immediately and some cells remain in an undifferentiated state and divide to replenish progenitor numbers. We have also identified in our cultures a small apolar GD3- cell, which when isolated differentiated into a GD3+ bipolar O-2A progenitor cell. We have termed this cell type a preprogenitor. The differentiation of this cell type into O-2A progenitors may be the source of the immature GD3+ cells present at the later stages of our secondary cultures. The proliferative profile of the cultures was studied using 5′bromo-2-deoxyuridine (BrdU) incorporation as an index of mitosis. Only the immature, bipolar O-2A progenitors were seen to divide at any time in serum-free culture. Neither the more mature multipolar O-2A cells nor the oligodendroglia were seen to divide. The developmental profile of the O-2A cells in the rat forebrain in vivo showed a largely similar progression to that in culture, with a time lag of at least 6 days between GD3 expression and the onset of myelination. BrdU incorporation studies in vivo also showed that the GD3+ progenitor cell is mitotic whereas the GC(+)-expressing oligodendroglia is not. We have shown that there are several significant alterations in the timing of antigen expression in both O-2A progenitors and oligodendroglia in vitro compared to that seen in vivo.

Oligodendroglial progenitor cells but not oligodendroglia divide during normal development of the rat cerebellum

To identify the stage in the life cycle of oligodendroglia at which they are mitotic during normal in vivo development [3H]thymidine autoradiography has been combined with immunocytochemistry on frozen sections of rat cerebellum. A panel of antibodies have been used that recognize antigens expressed by oligodendroglia at different stages of differentiation from progenitor to mature cell. It has been demonstrated that of the cells of the oligodendroglial lineage only the progenitors, identified by their expression of the ganglioside GD3, were seen to incorporate [3H]thymidine at all the developmental stages tested. Only few dividing GD3-positive cells were observed in the subventricular zones of the fourth-ventricle. The greatest number of dividing GD3-positive progenitors in the rat cerebellum was observed in the folia at postnatal day 7. Silver grains were never observed over cells that could be distinguished as oligodendroglia by their expression of galactocerebroside, 2'3'-cyclic nucleotide 3'-phosphohydrolase, or myelin basic protein. Mitotic astroglia were observed at all stages and could be clearly distinguished by their expression of glial fibrillary acidic protein and glutamine synthetase. When animals were injected with [3H]thymidine at postnatal day 7 and killed at 1-day intervals radiolabel was first observed in galactocerebroside-positive and 2'3'-cyclic nucleotide 3'-phosphohydrolase-positive oligodendroglia at day 9 and in myelin basic protein-positive cells at day 10-11, 3 days after the last cell division. Thus, we have demonstrated for the first time using in situ immunocytochemical techniques, a mitotic glial progenitor cell that is known to give rise to oligodendroglia both in vivo and in vitro.

Are some chondrule rims formed by impact processes? Observations and experiments

Observations and experimental evidence are presented to support the hypothesis that high-speed impact into a parent body regolith can best explain certain textures and compositions observed for rims on some chondrules. A study of 19 interclastic rimmed chondrules in the Weston (H 3/4) ordinary chondrite shows that two main rim types are present on porphyritic olivine-pyroxene (POP) and porphyritic pyroxene (PP) chondrules: granular and opaque rims. Granular rims are composed of welded, fine-grained host chondrule fragments. Bulk compositions of granular rims vary among chondrules, but each rim is compositionally dependent on that of the host chondrule. Opaque rims contain mineral and glass compositions distinctly different from those of the host, partially reacted chondrule mantle components, and some matrix grains. Opaque rims are greatly enriched in FeO (up to 63 wt%). The original chondrule pyroxene compositional zonation patterns and euhedral grain outlines are discontinuous at the chondrule/rim interface. Opaque rims are dominated by fayalitic olivine (Fa92-56), with high Al2O3 content (0.78-3.15%), which makes them distinctly different from primary olivine, but similar to Fe-olivine in chondrule rims of other meteorites. Thin zones of chondrule minerals adjacent to the present rims are intermediate in FeO content between the Mg-rich interior and the Fe-rich rim, which indicates a reaction relationship. Regardless of conclusions drawn regarding other types of rims, granular and opaque rim characteristics appear to be inconsistent with nebular condensation, in that host and matrix fragments are included within the rim. We have initiated a series of experiments, using the Ames two-stage light gas gun, to investigate the hypothesis that the Weston chondrule rims are the result of thermal and mechanical alteration upon impact into a low-density medium. Clusters of approximately 200-micron-sized silicate particles were fired into aerogel (density = 0.1 g cm-3) at velocities of 5.6, 4.7, and 2.2 km sec-1. Recovered grains show characteristics that range from fragmented projectile grains mixed with melted aerogel that nearly rim the grains to grains that have melted aerogel clumps mixed with partially melted projectile. These experimental results demonstrate that rim-like thermal and mechanical alteration of projectiles can result from a high-velocity encounter with a low-density target. Therefore, experiments using appropriately chosen projectile and target materials can provide a test of the hypothesis that chondrule rims common to Weston and possibly other ordinary chondrites were formed by such a process.

The rat glucagon gene is regulated by a protein kinase A-dependent pathway in pancreatic islet cells

A cAMP response element (CRE) has been identified in the proximal 5'-flanking region of the rat glucagon gene, and activation of the cAMP-dependent pathway in fetal rat intestinal cells leads to an increase in the levels of glucagon mRNA transcripts. In contrast, the human glucagon gene does not contain a similar CRE, and the results of studies using immortalized rat and hamster islet cell lines have suggested that glucagon gene expression may not be regulated by cAMP. To reconcile these observations, we have studied the control of glucagon gene expression. Incubation of primary rat islet cell cultures with forskolin in the presence of low (0.5 g/liter) or high (2.0 g/L) glucose resulted in a 2- to 3-fold increase in the levels of glucagon mRNA transcripts. Forskolin also stimulated the secretion and synthesis of immunoreactive glucagon. The importance of the protein kinase-A-dependent pathway in the regulation of glucagon gene expression was also examined in hamster islet InR1-G9 cells. Cotransfection of a glucagon-chloramphenicol acetyltransferase (CAT) fusion gene containing the glucagon CRE and a cDNA encoding the catalytic subunit of protein kinase-A resulted in stimulation of glucagon-CAT activity in hamster islet cells. Catalytic subunit cotransfection also activated somatostatin-CAT, but no activation of RSVCAT was detected. The results of these experiments suggest that the rat glucagon gene is regulated by a protein kinase-A-dependent pathway in the endocrine pancreas.

The effect of 5-fluorouracil at elevated temperatures on a spontaneous mouse tumour: Arrhenius analysis and tumour response

In a series of studies to investigate activation energies and thermal enhancements of various chemotherapeutic agents the effect of 5-fluoruracil (5FU), an antimetabolite, on murine tumour cells was studied at elevated temperatures. Animal tumours were early generation isotransplants of a spontaneous fibrosarcoma, FSa-II tumours, and C3Hf/Sed mice were used throughout. Cell survival curves for 5FU were obtained as a function of treatment time by in vitro treatment-in vivo lung colony assay at temperatures between 37.0 and 43.5 degrees C. The D0, or the treatment time to reduce surviving fraction from S to S/e in the exponential portion of the survival curve, decreased slightly from 37 degrees C treatment to 41.5 degrees C treatment. The D0 decreased substantially from 41.5 degrees C to 43.5 degrees C. Arrhenius-plot analysis indicated that the activation energies were 92.9 and 731 kJ/M at temperatures between 37 and 41.5 degrees C, and between 41.5 and 43.5 degrees C, respectively. The activation energy of 92.9 kJ/M for the temperature range from 37 to 41.5 degrees C was the lowest of the other agents, bleomycin, cis-diamminedichloroplatinum and 1,3-bis(2-chloroethyl)-N-nitrosourea, which have been investigated in our laboratory. This indicated that the thermal enhancement was smallest among these agents. In vivo experiments failed to demonstrate thermal enhancement of the anti-tumour effect of 5FU. Namely, combined 5FU and heat treatments at 41.5 and 43.5 degrees C did not prolong the tumour growth time compared with 5FU given at room temperature. No pH effect was found in an in vitro experiment and glucose administration did not enhance the anti-tumour effect of 5FU.

On the anisotropy of the canine diaphragmatic central tendon

We studied the mechanical and anatomical anisotropy of the canine diaphragmatic central tendon (CT). Dumb-bell-shaped strips with effective dimensions of 10 x 2 mm (length x width) were cut from different regions of the canine diaphragmatic CT in two different orientations relative to the direction of neighboring muscle fibers. Specimens sampled with their long axial dimension oriented parallel to the neighboring muscle fibers were named Group-1 and those sampled with an orientation perpendicular to the neighboring muscle fibers were named Group-2. Results from one-dimensional stress-strain and tensile failure strength tests revealed that the CT is a nonlinear, inelastic, and anisotropic material. Group-1 specimens were found to have a higher stiffness, higher failure strength and higher strain energy density at failure than Group-2 specimens. Polarized microscopy showed that multiple sheets of collagen fiber bundles formed an orthogonal network in the tendon. Collagen fiber bundles along Group-1 direction formed parallel trajectory lines connecting the neighboring costal and crural muscles; bundles along Group-2 direction were observed to orient 90 degrees away. At the central apex region of the CT, collagen bundles of Group-1 formed a fan-like trajectory pattern. This collagen network architecture was compared favorably to the trajectories of an approximated principal stress field in the CT due to simulated contractile forces from its adjacent costal and crural muscles. These combined results suggest a structure-function relationship for the anatomical and mechanical anisotropy in the canine diaphragmatic CT.

Analysis of genetic markers in forensic DNA samples using the polymerase chain reaction

The ability to extract and type DNA from forensic evidentiary samples has revolutionized the field of forensic serology. Previously, genetic marker typing was limited to the analysis of blood group markers and soluble polymorphic protein markers. Because the number of suitable markers expressed in particular fluids and tissues is relatively small, and because mixtures of fluids cannot be separated for conventional genetic marker typing, a suspect frequently cannot be included or excluded as a fluid donor in a case. However, the development of methods to extract DNA from virtually all biological specimens has greatly expanded the potential for individual identification. Of particular importance was the ability to extract mixtures of sperm cells and epithelial cells found in sexual assault cases such that the DNA from the sperm cells could be typed independently of the DNA from the victim's epithelial cells. Restriction fragment length polymorphism (RFLP) analysis was the first DNA-based method applied to problems of individual identification. This method, while powerful in its ability to differentiate individuals, is limited by the quantity and quality of DNA required for an unambiguous result and by the amount of time it takes to obtain a result. Despite these limitations, several laboratories are using RFLP analysis successfully for the detection of polymorphisms in forensic DNA case samples. While the field of forensic serology was being revolutionized by the prospect of DNA analysis, the field of molecular biology was being revolutionized by the invention of the polymerase chain reaction (PCR), which ultimately has had an impact on every area of biological science. The PCR DNA amplification technology is ideally suited for the analysis of forensic DNA samples in that it is sensitive and rapid and not as limited by the quality of DNA as the RFLP method. The focus of this article is the use of the PCR for typing genetic markers, and we will address specifically the special considerations that arise from applying DNA amplification and typing technology to forensic materials.

Ophthalmological and other toxicities related to cytosine arabinoside and total body irradiation as preparative regimen for bone marrow transplantation

Cytosine arabinoside, 3 g/m2, every 12 h for 6 days, followed by fractionated total body irradiation, 200 cGy twice daily for 3 days, was administered to 39 adult patients undergoing bone marrow transplantation. Allogeneic transplant patients received cyclosporin and methotrexate for prophylaxis of graft-versus-host disease. There were 21 autologous transplants (16 with acute leukemia, four with an advanced stage of chronic myelocytic leukemia, and one with lymphoma) and 18 allogeneic transplants (14 with acute leukemia, two with an advanced stage of chronic myelocytic leukemia and two with myelodysplastic syndrome). Toxicities were compared between the two groups. There was a significantly greater degree and duration of mucositis and a greater frequency of radiation-type retinopathy developing in the allogeneic group, predominantly in those having had radiation for prophylaxis or treatment of central nervous system leukemia. Seven of 11 acute leukemic patients who received autologous transplants in remission survive. Two of seven acute leukemias who received allogeneic transplants while in remission survive. Although the increased morbidity, retinitis and mucositis, observed in the allogeneic group indicates that this regimen when combined with methotrexate and cyclosporin is too toxic, the results in autologous transplantation in acute leukemia in remission are encouraging.

Malignant hyperthermia in the otolaryngologic patient: prospective anesthetic and surgical management of eight children

Malignant hyperthermia (MH) is a rare genetic myopathy whose hallmark is rise in body temperature. This hypermetabolic state is triggered by inhalational anesthetics and/or depolarizing muscle relaxants such as succinylcholine. Even the use of dantrolene may not be protective against the hypermetabolic crisis. Eight patients at risk for MH undergoing tonsillectomy, adenoidectomy, and/or myringotomy with ventilation tube insertion were anesthetized with nitrous oxide, barbiturates, opiates, tranquilizers, and nondepolarizing muscle relaxants without dantrolene and without complication. Cardiac monitoring and rectal temperatures were followed. In order to provide additional evidence, all eight patients had vastus lateralis muscle biopsies with subsequent caffeine-halothane contracture studies performed. The contracture study showed positive results in seven of eight patients studied, indicating MH-susceptible muscle. No anesthetic or operative complications were encountered. This study demonstrates that patients at risk of developing MH crisis can have otolaryngologic procedures performed relatively safely while undergoing appropriately selected anesthesia.

Cystine uptake by cultured cells originating from dog proximal tubule segments

Large numbers of kidney epithelial cells were cultured successfully from isolated dog proximal tubule segments. Cells in primary culture and in first passage retained the cystine-dibasic amino acid co-transporter system which is found in vivo and in freshly isolated proximal tubule segments. In contrast to other cultured cells, the cystine-glutamate anti-porter was absent in primary cultures. However, this anti-porter system seemed to be developing in cells in first passage. The intracellular ratio of cysteine:reduced glutathione (CSH:GSH) was maintained at 1:36 in both primary cultures and in low passage cells. Incubation of cells in primary culture for 5 min at 37 degrees C with 0.025 mM [35S]L-cystine resulted in incorporation of approximately 36 and 8.5% of the label into intracellular CSH and GSH, respectively. These cultured cells, therefore, seem to be an excellent model system for the eventual elucidation of a) the inticacies of cystine metabolism and b) regulation of 1) the cystine-dibasic amino acid co-transporter system and 2) the development of the cysteine-glutamate anti-porter system.

Partial amino acid sequences of several globin chains from the sockeye salmon, Oncorhynchus nerka

1. Partial amino acid sequences for several sockeye salmon hemoglobin beta-chains have been determined and compared to several other fish beta-chain sequences. 2. A 90% homology exists between the sockeye cathodal (C1) beta-chain and the trout Hb I beta-chain for residues 1-19. 3. The sockeye salmon anodal (A1-3) beta-chain is virtually identical to the trout HB IV beta-chain for the first 55 amino acid residues. 4. The alpha-chains of the sockeye salmon appear to be acetylated at the N-terminal position and about 0.6% of the sockeye hemoglobin is glycosylated.

Lack of effect of cimetidine on acetaminophen disposition in humans

The effect of cimetidine administration on the disposition of acetaminophen was evaluated in seven men and six women. One gram of acetaminophen was administered to each volunteer after an overnight fast on two occasions in a balanced crossover design with and without cimetidine, 300 mg every 6 hours beginning 50 hours before acetaminophen administration and continuing for 22 hours after. N-Acetylcysteine was administered on both occasions when acetaminophen was ingested to protect against glutathione depletion. Blood samples were collected serially for 12 hours after acetaminophen administration, and total urine volume was collected for 24 hours. Fractional clearances of acetaminophen through renal and metabolic routes (sulfation, glucuronidation, 3-hydroxylation, and glutathione conjugate formation) were not altered by cimetidine administration. Studies in microsomes prepared from two human organ donors indicated that cimetidine inhibited acetaminophen reactive metabolite formation noncompetitively, with Ki values of 0.35 mmol/L and 0.32 mmol/L for the respective livers, which is 5 to 10 times the putative cimetidine concentration required for therapeutic effect.

Immunohistochemical localization of myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphohydrolase in flattened membrane expansions produced by cultured oligodendrocytes

Oligodendrocytes, the cells responsible for myelin sheath formation in the central nervous system, were isolated from primary dissociated mixed glial cultures prepared from newborn mouse forebrain, and further cultured in a serum-free defined culture medium. Single and double indirect immunofluorescence using antibodies against the myelin glycolipids, galactocerebroside and sulfatide, and the myelin proteins, myelin basic protein and 2',3'-cyclic nucleotide 3'-phosphohydrolase, was used to investigate the composition of the flat membrane extensions produced by some oligodendrocytes in culture. Galactocerebroside and sulfatide were both expressed on the external surface of the plasma membrane of oligodendrocyte cell bodies and processes and also the membrane expansions. Neither myelin basic protein nor 2',3'-cyclic nucleotide 3'-phosphohydrolase were expressed on the external surface of oligodendrocytes. Myelin basic protein could be localized to the cell body and the membrane expansions but not the major and fine processes. The localization of these myelin components suggests that the expansions have characteristics of the mature myelin membrane. 2',3'-Cyclic nucleotide 3'-phosphohydrolase was found to be localized in the cell body, and in total contrast to myelin basic protein, in the major processes and the fine interconnecting processes, but not the membrane expansions. In some of the cells 2',3'-cyclic nucleotide 3'-phosphohydrolase was present at the outer extremities of the flat membrane sheets, giving the appearance of an extending growth region. Our results thus clearly show that 2',3'-cyclic nucleotide 3'-phosphohydrolase is localized within oligodendrocytes in discrete regions of plasma membranes and suggest that this protein has a possible role in the early stages of myelin formation.

Inhibition of the release of arachidonic acid prevents the development of sarcolemmal membrane defects in cultured rat myocardial cells during adenosine triphosphate depletion

Previous studies have suggested that phospholipid degradation is closely associated with the development of sarcolemmal membrane injury. This study was initiated to characterize the effects of synthetic inhibitors of phospholipase activities using a cultured myocardial cell model in which arachidonic acid is liberated after treatment with the metabolic inhibitor, iodoacetate. Pretreatment with a steroidal diamine (U26,384) blocked the degradation of labeled phosphatidylcholine and the release of arachidonic acid in cultured myocardial cells during ATP depletion. Inhibition of phospholipid degradation by U26,384 prevented the development of sarcolemmal membrane defects and the release of creatine kinase from the cultured myocardial cells during ATP depletion. Pretreatment with U26,384 had no significant effect on the extent of ATP depletion after iodoacetate treatment, which indicates that the activity of this compound could not be simply ascribed to a sparing effect on ATP concentration. These results support the hypothesis that the development of sarcolemmal membrane injury and the associated loss of cell viability are causally related to progressive phospholipid degradation. In addition, these studies indicate that the release of arachidonic acid during ATP depletion is associated with the net loss of the phosphatidylcholine molecule.

Expression of GD3 ganglioside by developing rat cerebellar Purkinje cells in situ

GD3 is a major ganglioside of the immature vertebrate CNS, and its expression is suggested to be characteristic of immature neuroectodermal cells. Using immunocytochemistry on cryostat sections of developing rat cerebellum with a monoclonal antibody specific for GD3, we have found that GD3 begins to be expressed on the plasma membrane of Purkinje cell bodies and dendrites beginning at postnatal day 7. Staining became brighter as the dendritic tree of the cells enlarged. As the Purkinje cells began to mature in different folia, they became GD3+, until by 15 days postnatal all Purkinje cells were GD3+. Positive staining of the dendritic tree was still present in the adult cerebellum. Using a monoclonal antibody 7-8D2, which recognizes cerebellar granule cells and their axons (the parallel fibres), and polyclonal antibodies against a synaptic vesicle component synaptophysin, double-immunofluorescence staining together with anti-GD3 antibodies suggested that the appearance of GD3 immunoreactivity did not correlate either with the ingrowth of parallel fibres or the presence of their synapses on Purkinje cell dendrites. However, comparison with earlier morphological studies showed that the appearance of GD3 immunoreactivity correlated well with the formation of climbing fibre synapses on Purkinje cell dendrites and the onset of the rapid expansion of the dendritic tree. These results are in keeping with the idea that elevated GD3 concentrations are found in certain cell types during periods of rapid growth or high metabolic activity but also show that this is not only restricted to immature cells.

Alpha 1-adrenergic stimulation of cardiac gene transcription in neonatal rat myocardial cells. Effects on myosin light chain-2 gene expression

Previous studies have demonstrated that alpha-adrenergic stimulation of cultured, neonatal rat myocardial cells results in an increase in intracellular volume and protein content of cultured neonatal rat myocardial cells. Utilizing this model of cardiac hypertrophy, we have examined the effects of alpha-adrenergic stimulation on the accumulation of sarcomeres and the expression of a rat cardiac myofibrillar gene, myosin light chain-2 (MLC-2). Following alpha-adrenergic stimulation, cultured myocardial cells displayed a severalfold increase in the number of sarcomeric units, as assessed by electron microscopy, an increase in cellular MLC-2 content, and a 2-3 fold increase in the steady state levels of MLC-2 mRNA. This effect of alpha-adrenergic stimulation was accompanied by a 2-3-fold increase in total transcriptional activity, which was dependent on the concentration and duration of exposure to the agonist, and displayed alpha 1-adrenergic receptor specificity. The transcriptional response was not immediate, with a lag period of at least 1 h, and a maximal effect required continuous occupancy of the receptor. The increase in steady state levels of MLC-2 mRNA is regulated, in part, at the level of transcription of the cardiac MLC-2 gene. These results suggest that alpha 1-adrenergic stimulation may be important in the growth of the neonatal heart through the activation of total transcriptional activity. In addition, increases in the levels of myofibrillar proteins during myocardial cell growth and hypertrophy, may be mediated in part by the stimulation of transcription of myofibrillar genes.

Development of macroglial cells in rat cerebellum. I. Use of antibodies to follow early in vivo development and migration of oligodendrocytes

The origin of oligodendrocytes and astrocytes in the CNS is still a focus of much experimentation and controversy. We have used antibodies against ganglioside GD3 and galactocerebroside (GC) to follow the origin and development of rat cerebellar oligodendrocytes both in vitro and in vivo. The immunofluorescent identification of GC+ cells in the rat neonatal cerebellum in vivo, revealed that cells initially GD3+/GC- appeared to make the transition via GD3+/GC+ cells to GD3-/GC+ oligodendrocytes. This sequence of events closely paralleled the maturation of cerebellar oligodendrocyte precursors found in serum-free dissociated culture. In contrast, whereas both GD3+ and glial fibrillary acidic protein-positive cells were seen in serum-containing dissociated culture and also in freshly dissociated suspensions of cerebellum at postnatal days 0 to 6, such cells could not be identified in situ. Putative GD3+/GC- oligodendrocyte precursor cells arose from the deeper regions of the cerebellum at birth, perhaps initially from the superior medullary velum adjacent to the fourth ventricle, and appeared to migrate into the developing folia just prior to myelination and the acquisition of GC.

Stress-induced malignant hyperthermia in a head-injured patient. Case report

Susceptibility to malignant hyperthermia is a rare inherited myopathy. Hypermetabolic crises accompanied by a rise in body temperature to as high as 44 degrees C are the hallmark of malignant hyperthermia episodes. These are triggered by inhalational anesthetic agents or depolarizing muscle-relaxant drugs. A similar condition exists in pigs; however, in addition to drug-induced attacks, episodes of malignant hyperthermia occur in these animals as a result of stress. It has been proposed that stress-induced malignant hyperthermia occurs in man. The present paper presents a case of stress-induced malignant hyperthermia in a 21-year-old man in whom the inciting stress was a head injury.

Development of macroglial cells in rat cerebellum. II. An in situ immunohistochemical study of oligodendroglial lineage from precursor to mature myelinating cell

Using immunofluorescence with a panel of antibodies that recognize antigens expressed by oligodendroglia, the myelin-producing cells of the CNS, at different stages of differentiation from precursor to mature cell, we have investigated the development of cells of this lineage in cryostat sections of rat cerebellum. Our results are consistent with the view that glial precursors, identified by their expression of the ganglioside GD3, arise in the subependymal layers of the 4th ventricle and migrate to their final position in the cerebellum via the superior medullary velum, and to some extent the peduncles. As the cells reach their final destination they make the transition to recognizable galactocerebroside (GC)-expressing oligodendroglia, via a GD3+/GC+ intermediate. The myelin-associated protein 2′,3′-cyclic nucleotide 3′-phosphohydrolase (CNP) appears at the same time as GC, whereas myelin basic protein (MBP) is expressed 2–3 days after GC and CNP, immediately prior to myelin formation. A very clear progression of oligodendroglial differentiation was observed from the SMV into the base of the cerebellum, up into the white matter (WM) tracts of the folia, and then away from this central white matter into the granule cell and Purkinje cell layers, and finally the molecular layer. The time delay between the expression of GC, CNP and MBP was the same for oligodendroglia in all of these layers, suggesting the presence of an intrinsic clock controlling the initial expression of these myelin components. The early appearance of CNP in oligodendroglia suggests a role for this protein in the early stages of myelinogenesis.

Long-term survival following levamisole or placebo adjuvant treatment of colorectal cancer: a Western Cancer Study Group Trial

In 1976, the Western Cancer Study Group initiated a prospectively randomized, double-blind trial of an 18-month adjuvant program comparing levamisole with placebo treatment following surgical resection in patients with colorectal adenocarcinoma. After stratification for site of disease (colon vs. rectum) and stage (B vs. C), 78 patients were entered. The levamisole schedule was 2.5 mg/kg/day given on days 1 and 2 of each week. The median follow-up of entered patients is now 7.5 years. Toxic effects of treatment were minimal. However, no long-term survival advantage was associated with levamisole compared to placebo administration in this population with resected large-bowel adenocarcinoma.

Expression of the 2',3'-cyclic nucleotide 3'-phosphohydrolase gene and immunoreactive protein in oligodendrocytes as revealed by in situ hybridization and immunofluorescence

In order to investigate the role of the myelin-associated enzyme 2' 3'-cyclic nucleotide 3'-phosphohydrolase in the development of the myelin sheath, as well as genetic factors involving dysmyelinating disorders, we have recently isolated and sequenced cDNAs corresponding to the CNPase protein. In this study we have used 32P-labeled bovine CNPase cDNA probes to localize the messenger RNA coding for this enzyme in mouse cerebral and cerebellar cryostat sections and have compared our data with the distribution of the CNPase protein as revealed by immunofluorescence. Specific labeling was localized to the white matter fiber tracts and, in many areas, to individual oligodendrocyte cell bodies. The corpus callosum and the white matter of the cerebellum were heavily labeled. Distribution of the CNPase protein, as detected by immunohistochemical studies, was parallel to that of the CNPase mRNA as detected by in situ hybridization histochemistry, with oligodendrocyte cell bodies and their processes intensely labeled. This study provides strong evidence that the CNPase gene is expressed in the myelin-producing cells of the central nervous system and that CNPase is synthesized by and stored within oligodendrocytes.

Oligodendroglial and astroglial heterogeneity in mouse primary central nervous system culture as demonstrated by differences in GABA and D-aspartate transport and immunocytochemistry

Using simultaneous autoradiography and immunofluorescence we have investigated the functional heterogeneity amongst oligodendrocytes and astrocytes in primary mouse central nervous system (CNS) culture as expressed by differences in their ability to accumulate gamma-[3H]aminobutyric acid [( 3H]GABA) and D-[3H]aspartate. We have used a range of specific antibodies that identify oligodendrocytes and astrocytes, from precursor to fully mature cells, to address the question of whether all neuroglial cells are capable of expressing this function. Our results showing that A2B5-, 03-, and galactocerebroside-positive cells became heavily labelled with these two neuroactive amino acids, whereas cells expressing the myelin proteins 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) and myelin basic protein (MBP) did not, demonstrate that this capacity is already present in oligodendrocytes at early developmental stages but may not extend to fully mature cells. Astrocytes in culture exhibited a large degree of variability with respect to their ability to transport GABA and D-aspartate. When grown in either serum-containing or serum-free hormone supplemented culture medium two morphologically distinct of glial fibrillary acidic protein (GFAP)-positive astrocyte were identified, process-bearing and epithelioid. Process-bearing cells became heavily labelled with the amino acids under both growth conditions, whereas, data showed that although epithelioid astrocytes were not, or only lightly, labelled with either amino acid in serum-containing cultures, when grown in serum-free culture medium they became more heavily labelled. Thus the expression, in culture, by epithelioid astrocytes, of one of the functions attributed to these cells is largely dependent on growth conditions.