Assembly and secretion of fibrinogen. Degradation of individual chains

Hep G2 cells produce surplus A alpha and gamma fibrinogen chains. These excess chains, which are not secreted, exist primarily as free gamma chains and as an A alpha-gamma complex. We have determined the intracellular location and the degradative fate of these polypeptides by treatment with endoglycosidase-H and by inhibiting lysosomal enzyme activity, using NH4Cl, chloroquine, and leupeptin. Free gamma chain and the gamma component of A alpha-gamma are both cleaved by endoglycosidase-H, indicating that the gamma chains accumulate in a pre-Golgi compartment. Lysosomal enzyme inhibitors did not affect the disappearance of free gamma chains but inhibited A alpha-gamma by 50%, suggesting that A alpha-gamma is degraded in lysosomes. The degradative fate of individual chains was determined in transfected COS cells which express but do not secrete single chains. Leupeptin did not affect B beta chain degradation, had very little affect on gamma chain, but markedly inhibited A alpha chain degradation. Antibody to immunoglobulin heavy chain-binding protein (GRP 78) co-immunoprecipitated B beta but not A alpha or gamma chains. Preferential binding of heavy chain-binding protein to B beta was also noted in Hep G2 cells and in chicken hepatocytes. Taken together these studies indicate that B beta and gamma chains are degraded in the endoplasmic reticulum, but only B beta is bound to BiP. By contrast A alpha chains and the A alpha-gamma complex undergo lysosomal degradation.

Prostatic abscess due to Candida tropicalis in a nonacquired immunodeficiency syndrome patient

We report a case of prostatic abscess due to Candida tropicalis in a nonacquired immunodeficiency syndrome patient with diabetes. The diagnosis and management are discussed, and the literature is reviewed.

Dietary iron loading does not influence biliary iron excretion in rats

The effect of dietary iron loading on biliary iron excretion was investigated with male Wistar rats aged 6 wk. The rats were fed purified diets with either 174 or 1740 mg FeSO4. 7H2O/kg diet and demineralized water for 6 wk. Blood haemoglobin, hematocrit, and iron concentrations in kidney and heart were not affected and iron concentrations in liver, spleen, and tibia were significantly raised after feeding the high-iron diet. The high-iron diet did not raise biliary iron excretion, suggesting that biliary iron excretion does not play an important role in regulating iron metabolism in rat after dietary iron loading.

Dentin bond shear strength and microleakage for Syntac/Heliomolar: a comparison between the manufacturer's and total etch technique

Recent improvements in formulation have led to significant improvements in the bond strength and clinical performance of dentin bonding agents. The growing interest in the concept of total etch prompted a comparison between manufacturer-recommended procedure and that of total etch for the product Syntac. An in vitro study to examine shear bond strength to dentin and microleakage and an in vivo component to investigate the micromorphologic relationship between restoration and tissue was conducted. No statistical significance was observed in bond strength values for the nonetched versus the etched group. Significantly, however, a larger number of specimens in the nonetched group exhibited microleakage. In vivo, only the etched group exhibited a zone of hybridization although both nonetched and etched restorations showed no interfacial gaps. It was concluded that total etch does not compromise the shear bond strength of Syntac but it appears to significantly reduce microleakage possibly due to the formation of a hybrid zone and may have merit clinically.

[Comparison of constituents in Pueraria thomsonii Benth before and after processing]

Determinations of aqueous extract, alcoholic extract, flavonoids and puerarin as well as ten inorganic elements in Pueraria thomsonii have been made before and after processing. The results showed that the above mentioned ingredients all varied in amount.

Fragile X syndrome without CCG amplification has an FMR1 deletion

We describe a patient with typical clinical features of the fragile X syndrome, but without cytogenetic expression of the fragile X or an amplified CCG trinucleotide repeat fragment. The patient has a previously uncharacterized submicroscopic deletion encompassing the CCG repeat, the entire FMR1 gene and about 2.5 megabases of flanking sequences. This finding confirms that the fragile X phenotype can exist, without amplification of the CCG repeat or cytogenetic expression of the fragile X, and that fragile X syndrome is a genetically homogeneous disorder involving FMR1. We also found random X-inactivation in the mother of the patient who was shown to be a carrier of this deletion.

Experience with direct molecular diagnosis of fragile X

The utility of the pfxa3 probe for direct molecular diagnosis of the fragile X (FRAXA) has been established. This probe detects amplification of an unstable DNA element consisting of variable length CCG repeats. The size of the amplified fragment is correlated with phenotype and was determined using PstI digested DNA in family members. In 35 families with the fragile X, there was correspondence in 183 cases between the presence of an amplified unstable element and the presence of the fragile X chromosome independently determined by cytogenetics, position in the pedigree, or linked DNA markers flanking the fragile X. There was also correspondence in 124 cases between the presence of the normal 1.0 kb PstI fragment and absence of the fragile X chromosome independently determined by linked flanking markers. Six additional families considered to be isolated cases of 'fragile X' had been diagnosed before recognition of FRAXD. The pfxa3 probe confirmed the cytogenetic diagnosis in three families, the other three being rediagnosed as non-fragile X. A further two families had consistent expression of a different folate sensitive fragile site, FRAXE, close to FRAXA but not associated with fragile X syndrome and not detectable with the pfxa3 probe. Subsequent referrals were received from additional family members or from members of new families for whom carrier status had not been predetermined by linked markers. Direct pfxa3 diagnosis for the 135 females within these 222 additional cases was confirmed by dosage analysis with the control probe pS8.(ABSTRACT TRUNCATED AT 250 WORDS)

Fragile-X syndrome: unique genetics of the heritable unstable element

The fragile site at Xq27.3 is an unstable microsatellite repeat, p(CCG)n. In fragile-X syndrome pedigrees, this sequence exhibits variable amplification, the length of which correlates with fragile-site expression. There is a direct relationship between increased p(CCG)n copy number and propensity for instability: individuals having large amplifications exhibit somatic variation due to increased instability. The instability of the p(CCG)n repeat, when transmitted through affected pedigrees, explains the unusual segregation patterns of fragile-X phenotype, referred to as the Sherman paradox. All individuals of fragile-X genotype were found (where testing was possible) to have a parent with amplified p(CCG)n repeat, indicating that few, if any, cases of fragile-X syndrome are not familial.

Effects of acute pentobarbital administration on GABAA receptor-regulated chloride uptake in rat brain synaptoneurosomes

Effects of acute pentobarbital administration on GABAA receptor-regulated muscimol-stimulated, pentobarbital-stimulated, or flunitrazepam-enhanced, muscimol-stimulated chloride uptake were studied in the brains of Sprague-Dawley rats. Animals received sodium pentobarbital, 60 mg/kg IP, and cerebral cortical and cerebellar synaptoneurosomes were isolated at 10 min, 1 h, and when animals had awakened. The basal uptake of chloride was not changed in either cerebral cortex or cerebellum at different time periods after pentobarbital administration. Ten minutes after sodium pentobarbital administration, muscimol-stimulated chloride uptake was significantly reduced in cerebellum when the muscimol concentration was 2.5, 5, or 20 microM and in cerebral cortex when the concentration of muscimol was 5 or 10 microM (p less than 0.05, Duncan multiple-range test). One hour after pentobarbital administration or after animals had awakened, chloride uptake in brains from pentobarbital-treated animals was less at low concentration of muscimol (2.5 microM). No significant difference was found in either cerebral cortex or cerebellum in pentobarbital-(125-1,000 microM) stimulated or flunitrazepam-(2.5-20 microM) enhanced, muscimol-(3 microM) stimulated chloride uptake at different time periods after pentobarbital administration. Saline treatment had no effects on the basal or muscimol-stimulated chloride uptake in cerebellar synaptoneurosomes when compared with naive animals. The results demonstrate that GABAA receptor-regulated chloride uptake is decreased after acute pentobarbital administration, an effect that is reversible.

Optical isomers of a leukotriene B4 antagonist have differential effects on granulocyte diapedesis in the guinea pig dermis

Leukotriene B4 (LTB4) is a proinflammatory product of arachidonic acid metabolism that has been implicated in a number of inflammatory diseases. When injected intradermally into the guinea pig, LTB4 has been shown to elicit a dose-dependent infiltration of granulocytes as assessed by the level of the neutrophil marker enzyme myeloperoxidase. SC-41930 [7-[3-(4-acetyl-3-methoxy-2-propylphenoxy)propoxy]-3,4-dihydro-8- propyl-2H-1-benzopyran-2-carboxylic acid] is a potent LTB4 receptor antagonist. When compounds were coadministered along with LTB4 (35 ng) into the dermal site, racemic SC-41930, (+)-SC-41930, and (-)-SC-41930 each inhibited granulocyte accumulation with ED50 values of 340 +/- 30, 98 +/- 5.7, and 1000 +/- 142 ng, respectively; when given intravenously inhibited with ED50 values of 0.5 +/- 0.06, 0.3 +/- 0.04, and 1.4 +/- 0.19 mg/kg, respectively; and when given intragastrically inhibited with ED50 values of 1.7 +/- 0.20, 1.4 +/- 0.23, and 3.0 +/- 0.41 mg/kg, respectively.

Effects of barbiturates on GABA system: comparison to alcohol and benzodiazepines

Central nervous system depressants, e.g. barbiturates, alcohol and benzodiazepines, have a wide spectrum of activity in humans and animals. Evidence accumulated suggests that some of the pharmacological actions exerted by these agents may be mediated through GABA system by mimicking GABAergic transmission. This proceeding briefly summarizes the evidence presented in our previous review (Yu S and Ho Ik: Alcohol 7: 261, 1990) as to how the GABA system plays a part in the barbiturate actions and the development of tolerance to and physical dependence on barbiturates. The comparisons of the effects of alcohol, barbiturates and benzodiazepines at different steps of GABA synapse are also discussed. Furthermore, the results which have been reported in the literature are inconsistent. This may be due to differences in (a) animal models used; (b) brain regions used; (c) protocols (dose, duration, form and route of administration, etc.) used in treating animals and/or (d) techniques (pharmacological, biochemical, physiological, etc.) used.

Fragile X syndrome: genetic localisation by linkage mapping of two microsatellite repeats FRAXAC1 and FRAXAC2 which immediately flank the fragile site

We report the genetic localisation of the fragile site at Xq27.3 associated with fragile X syndrome. The position of the fragile site within the multipoint linkage map was determined using two polymorphic microsatellite AC repeat markers FRAXAC1 and FRAXAC2. These markers were physically located within 10 kilobases and on either side of the p(CCG)n repeat responsible for the fragile site. FRAXAC1 has five alleles with heterozygosity of 44% and is in strong linkage disequilibrium with FRAXAC2 which has eight alleles and a heterozygosity of 71%. No recombination was observed either between these markers in 40 normal CEPH pedigrees or with the fragile X in affected pedigrees. These markers provide the means for accurate diagnosis of the fragile X genotype in families by rapid polymerase chain reaction analysis and were used to position the fragile X within the multipoint map of the X chromosome to a position 3.7 cM distal to DXS297 and 1.2 cM proximal to DXS296.

The therapeutic and biological effects of total lymph node irradiation and autologous bone marrow infusion on malignant lymphoma patients

Forty patients with malignant lymphoma were treated by 60Co total lymphoid irradiation (TLI): 21 cases received 6 Gy and 19 received 8 Gy. Ten also received autologous bone marrow infusion (ABMI). Acute radiation damage with digestive tract reaction and hemopoietic and immunological depression was observed. Bone marrow was depressed. WBC and platelets decreased rapidly. Lymphocytes showed quantitative and qualitative changes even at the early stage. All these symptoms subsided within 40 days. TLI accompanied by irradiation of the tumor site could result in effective control. The 1-, 3-, and 5-year survival rates of malignant lymphoma patients were 30/40 (75%), 14/24 (58%) and 4/12 (33%), respectively, while in those with Hodgkin's disease alone, the 1- and 3-year survival rates were 10/13 (76%) and 5/7 (71.4%), respectively. ABMI hastened hemopoietic reconstitution, which recovered relatively quickly after TLI.

Isolation of a human DNA sequence which spans the fragile X

To identify the sequences involved in the expression of the fragile X and to characterize the molecular basis of the genetic lesion, we have constructed yeast artificial chromosomes (YACs) containing human DNA and have screened them with cloned DNA probes which map close to the fragile site at Xq27.3. We have isolated and partly characterized a YAC containing approximately 270 kb of human DNA from an X chromosome which expresses the fragile X. This sequence in a yeast artificial ring chromosome, XTY26, hybridizes to the two closest DNA markers, VK16 and Do33, which flank the fragile site. The human DNA sequence in XTY26 also spans the fragile site on chromosome in situ hybridization. When a restriction map of XTY26, derived by using infrequently cutting restriction enzymes, is compared with similar YAC maps derived from non-fragile-X patients, no large-scale differences are observed. This YAC, XTY26, may enable (a) the fragile site to be fully characterized at the molecular level and (b) the pathogenetic basis of the fragile-X syndrome to be determined.

Hereditary unstable DNA: a new explanation for some old genetic questions?

Fragile X syndrome, associated with the fragile X chromosome, is the most common cause of familial mental retardation. The condition is characterised by a heritable DNA sequence that consists of an abnormal number of CCG repeats, and which is unstable in both mitosis and meiosis. We suggest that such heritable unstable DNA sequences could be present in other parts of the genome and that these might explain a number of genetic events that are not well understood in terms of classic genetic mechanisms. Such poorly explained observations include anticipation, incomplete penetrance, variable expression, and possibly imprinting, variegation, and multifactorial inheritance.

Magnetic resonance imaging and anatomy of the spine

This article deals with the detailed anatomy of the spine most pertinent to magnetic resonance (MR) imaging. The cervical and lumbar regions, the pediatric spine, and the intervertebral discs are emphasized. High resolution MR images of cadaver spines obtained from a 1.5 tesla imager were compared with cryomicrotome sections. This correlative study provided meaningful anatomic information for accurately interpreting and better understanding MR images of living patients.

Mapping of DNA instability at the fragile X to a trinucleotide repeat sequence p(CCG)n

The sequence of a Pst I restriction fragment was determined that demonstrate instability in fragile X syndrome pedigrees. The region of instability was localized to a trinucleotide repeat p(CCG)n. The sequence flanking this repeat were identical in normal and affected individuals. The breakpoints in two somatic cell hybrids constructed to break at the fragile site also mapped to this repeat sequence. The repeat exhibits instability both when cloned in a nonhomologous host and after amplification by the polymerase chain reaction. These results suggest variation in the trinucleotide repeat copy number as the molecular basis for the instability and possibly the fragile site. This would account for the observed properties of this region in vivo and in vitro.

Fragile X genotype characterized by an unstable region of DNA

DNA sequences have been located at the fragile X site by in situ hybridization and by the mapping of breakpoints in two somatic cell hybrids that were constructed to break at the fragile site. These hybrids were found to have breakpoints in a common 5-kilobase Eco RI restriction fragment. When this fragment was used as a probe on the chromosomal DNA of normal and fragile X genotype individuals, alterations in the mobility of the sequences detected by the probe were found only in fragile X genotype DNA. These sequences were of an increased size in all fragile X individuals and varied within families, indicating that the region was unstable. This probe provides a means with which to analyze fragile X pedigrees and is a diagnostic reagent for the fragile X genotype.

Restoration of lymphocyte proliferation and CTL generation by murine rIL-2 after treatment of allogeneic stimulator cells by ultraviolet B irradiation, heat, or paraformaldehyde

Following a 5-day mixed lymphocyte culture (MLC), C3H/HeJ (H-2k) splenocytes stimulated with DBA/2 (H-2d) gamma-irradiated splenocytes (2000 rads) are specifically cytotoxic in a 4-hr 51Cr-release assay to P815 (H-2d) target cells (62 +/- 2% cytolysis) but not to third-party EL4 (H-2b). However, when the DBA/2 stimulator cells were treated with heat inactivation (45 degrees C for 1 hr), fixed with 1% paraformaldehyde (15 min), or irradiated with ultraviolet-B light (10(4) J/M2), no cell proliferation or cytolytic activity developed in the MLCs. The levels of IL-1, IL-2, and IL-6 from the supernatants of MLC using stimulators undergoing either of the three treatments were markedly decreased compared with that from gamma-irradiated stimulators. Both cell proliferation and specific cytolysis were restored in a dose-dependent fashion by the addition of murine rIL-2 to the MLCs. If the stimulator cells were first activated with 5 micrograms/ml pokeweed mitogen or lipopolysaccharide for 2 days, the subsequent treatment with heat, paraformaldehyde, or UV-B did not significantly affect the development of cytolysis (54-70% cytolysis). Suppressor cells were not detected when cells from the nonresponsive MLCs (2.5 x 10(6) cells) were added to an MLC freshly prepared with gamma-irradiated stimulator cells, or were injected intraperitoneally (50 x 10(6) cells) into naive mice 2 days before recovery and in vitro sensitization of splenocytes. Therefore, modification of the stimulating alloantigen can prevent the release of cytokines that function as an essential second signal in the development of the proliferative response and subsequent cytolysis. The cytokine found to be essential for restoration of this response is IL-2.

[Miliary tuberculosis. Report of 4 cases proved by autopsy]

Four cases of acute miliary tuberculosis, including one case of nonreactive tuberculosis, are reported in this article. Final diagnoses were proved by autopsy. Literature review shows that symptoms of the disease vary greatly in different cases, but fever with unknown causes and overwhelming infection is the constant features. Nonreactive tuberculosis is common in the patients with low immunity and correct diagnosis depends on autopsy in most cases. Anti-tuberculosis drugs for nonreactive tuberculosis is not very effective and the prognosis is unfavourable. This article provides for the doctors with the experience of mis-diagnosis of acute miliary tuberculosis, especially nonreactive tuberculosis.

[Research on the processing of Angelica based on the analysis of water soluble constituents]

In this paper, a comparative study on the contents of water-soluble and alcohol-soluble tannin and ferulic acid in Angelica and its processed products is reported. The result shows that different processing methods have significant effects on the above constituents, thus administering to the interpretation of the theory of Angelica processing.

[Field survey of sarcocystis infection in the Tibet autonomous region]

Fecal specimens of 926 persons from Duilongdeqing, Milin and Linzhi counties of Tibet were examined by the zinc sulfate flotation method. The prevalences of Sarcocystis hominis in the three counties were 20.5%, 22.5% and 22.9% respectively (P greater than 0.05), with an average of 21.8%, and those of Sarcocystis suihominis were 0, 0.6% and 7.0% respectively (P less than 0.01). No significant difference in infection rate was found between different age or sex groups. Sarcocystis was detected in 42.9% of beef specimens from the market. Obviously, sarcocystis infection in Tibetans is usually caused by eating raw or undercooked beef or pork. The infected cases were generally asymptomatic, 9/10 and 5/5 of cases showed negative stool examination one month after being treated by sulfadiazine or finidazole respectively.

Intervertebral disk: normal age-related changes in MR signal intensity

The effect of age on the signal intensity of normal lumbar intervertebral disks was studied. Twenty-seven cadavers ranging in age from newborn to 79 years were studied with use of a 1.5-T magnetic resonance (MR) imager within 48 hours of death. The signal intensity in the central area of the disk was measured on a sagittal image obtained with a long repetition time (TR) and a long echo time (TE) and correlated to the age. A significant correlation between the decrease in signal intensity and age was found, although signal intensity changed less than 6% in 80 years. The decrease in signal intensity is concomitant with decreases in water and glycosaminoglycans and increases in collagen in the disk.

Effects of GABA antagonists, SR 95531 and bicuculline, on GABAA receptor-regulated chloride flux in rat cortical synaptoneurosomes

Synaptoneurosomes isolated from cerebral cortices of male Sprague-Dawley rats were used for studying GABAA receptor-regulated chloride influx. The in vitro effects of GABA antagonists, SR 95531 (a pyridazinyl GABA derivative) and bicuculline, on pentobarbital-stimulated, muscimol-stimulated or flunitrazepam-enhanced, muscimol-stimulated chloride uptake were studied. The chloride uptake was determined at 30 degrees C, for 5 sec. Pentobarbital and muscimol produced a maximal stimulation of chloride uptake in cortical synaptoneurosomes at 500 microM and 50 microMs, respectively. SR 95531 as well as bicuculline had no effect on the basal uptake of chloride. Whereas, SR 95531 (0.3 - 30 microM) and bicuculline (0.1 - 100 microM), when added 5 min before muscimol (50 microM), produced a significant concentration-dependent inhibition of muscimol (50 microM)-stimulated chloride uptake (IC50S of 0.89 +/- 0.11 microM and 13.45 +/- 2.10 microM, respectively). In studies of the inhibitory effects of SR 95531 and bicuculline on pentobarbital (500 microM)-stimulated chloride uptake, the IC50S were 0.81 +/- 0.12 microM and 3.86 +/- 1.14 microM, respectively. SR 95531 exhibited a more potent inhibitory effect than bicuculline on flunitrazepam-enhanced, muscimol-stimulated chloride uptake. The results revealed that SR 95531 has a more potent antagonistic effect than bicuculline on GABAA-regulated chloride flux.

Effect of axial loading on neural foramina and nerve roots in the lumbar spine

The hypothesis that the neural foramina in some patients are critically narrowed by axial compression of the spine has not been studied with direct imaging techniques. Frozen cadaveric motion segments of the lumbar spine (intervertebral disk and contiguous vertebrae) were imaged with computed tomography (CT). The segments were thawed and compressed in a hydrostatic press to simulate axial loading, and then the segments were frozen and imaged again. The motion segments were subsequently sectioned with a cryomicrotome, and the chronic degenerative changes present in the disks were classified. Pre- and post-compression CT images were compared, and anatomic relationships were studied. In 41 randomly selected segments (some with preexisting radial, transverse, and concentric annular tears), compression diminished the diameters and cross-sectional areas of the spinal canal and neural foramina. In no cases were nerve roots displaced, distorted, or compressed by axial loading. This study suggests that axial loading, such as that produced by ordinary weight bearing, does not critically compromise the neural foramina even in the presence of chronic degenerative disk changes.

[History and prospects of application of traditional Chinese drug beimu]

This paper deals with the history of the traditional Chinese drug Beimu and the emergence of Chuan Beimu and Zhe Beimu. The prospects of these drugs are also discussed in the light of their actual application in China.

Tyramine-O-sulfate, in addition to tyrosine-O-sulfate, is produced and secreted by HepG2 human hepatoma cells, but not by 3Y1 rat embryo fibroblasts

The spent media of HepG2 human hepatoma cells and 3Y1 rat embryo fibroblasts labeled with [35S]sulfate, upon ultrafiltration, were analyzed by a two-dimensional thin-layer separation procedure. Autoradiographs of the cellulose thin-layer plate revealed the presence of tyramine-O-[35S]sulfate in addition to tyrosine-O-[35S]sulfate in spent medium from human hepatoma cells. In contrast, only tyrosine-O-[35S]sulfate was observed in spent medium of 3Y1 rat fibroblasts. Using adenosine, 3'-phosphate, 5'-phospho[35S]sulfate as the sulfate donor, sulfotransferase(s) present in HepG2 cell homogenate catalyzed the sulfation of tyramine to tyramine-O-[35S]sulfate, but not the sulfation of tyrosine to tyrosine-O-[35S]sulfate. Endogenous aromatic amino acid decarboxylase present in HepG2 homogenate was shown to catalyze the decarboxylation of [3H]tyrosine to form [3H]tyramine while attempts to use it for the decarboxylation of tyrosine-O-sulfate to form tyramine-O-sulfate were unsuccessful. These results suggest that tyramine-O-sulfate may be derived from the de novo sulfation of tyramine, instead of the decarboxylation of tyrosine-O-sulfate.

[A primary study on molecular epidemiology of diarrhea caused by enterotoxigenic Escherichia coli by DNA colony hybridization using three enterotoxigenic gene-probes]

921 isolates of acute-diarrhea-inducing E. Coli strains from several provinces and cities, including Guangzhou, Wuhan, Sichuan, Shenyang and Hunan, have been collected during 1984-1989 and were identified in 1989 for detecting genes coding for these enterotoxins-LT, ST-P, ST-H by DNA colony hybridization using three enterotoxigenic gene probes. Of all the isolates homologous to these genes encoding LT, ST-P, ST-H and both LT and ST were 198 (21.5%), 131 (14.2%), 54 (5.9%) and 18 (2.1%), respectively. It was showed that in our country pathogenic agents of acute infectious diarrheal disease with ETEC strains first might be ETEC-LT strains, secondary ETEC-ST-H strains. Whereas, in rural districts ETEC-ST-P possess higher proportion of ETEC strains. These results provided some essential data and advanced methods for researching further molecular epidemiology of the ETEC diarrheal disease.

Effects of acute barbiturate administration, tolerance and dependence on brain GABA system: comparison to alcohol and benzodiazepines

Central nervous system depressants, e.g., barbiturates, alcohol and benzodiazepines, have a wide spectrum of activity in humans and animals. Evidence accumulated suggests that some of the pharmacological actions exerted by these agents may be mediated through GABA system by mimicking GABAergic transmission. This review attempts to summarize the evidence available as to how the GABA system plays a part in the barbiturate actions and the development of tolerance to and physical dependence on barbiturates. The comparisons of the effects of alcohol, barbiturates and benzodiazepines at different steps of GABA synapse are also presented. Furthermore, the results which have been reported in the literature are inconsistent. This may be due to differences in: (a) animal models used; (b) brain regions used; (c) protocols (dose, duration, form and route of administration, etc.) used in treating animals and/or (d) techniques (pharmacological, biochemical, physiological, etc.) used.

Augmentation of cell-mediated cytotoxicity following 50% partial hepatectomy

The cytolytic responses of C3H/HeJ mice after 50% hepatectomy (PH) were assessed in a 4-hr 51Cr-release assay. Spleen cells (SC) (50 x 10(6] from normal or PH C3H/HeJ (H-2k) mice were sensitized with equal numbers of irradiated allogeneic DBA/2 (H-2d) spleen cells in a five-day mixed lymphocyte culture. Generated cytolytic activity was measured against 51Cr-labeled P815 mastocytoma (H-2d) and EL4 lymphoma (H-2b) target cells. The wet weight and cell numbers per spleen following 50% partial hepatectomy were 70% and 75% higher than the control values for the first 20 days, and then returned to normal levels by 21 days. The cytolysis by spleen cells from 2-, 14-, and 31-day PH mice were 89.3 +/- 0.7, 86.9 +/- 5.3, and 90.1 +/- 1.3%, respectively, compared with control (sham-operated) values of 56.0 +/- 1.0, 57.0 +/- 2.0, and 49.9 +/- 7.0% (P less than 0.03 at E/T 100:1). This enhanced cytolysis by PH spleen cells remained high for at least 118 days after the liver resection before returning to control levels by 268 days. Cytolytic effector cells in PH SC were generated at least 24 hr earlier than in control SC. When normal and PH cytolysis were compared following primary and secondary in vitro sensitization, the cytolytic levels of primarily-sensitized PH spleen cells were comparable to secondarily sensitized normal spleen cells. Furthermore, the primarily sensitized normal spleen cells did not show crossreactive cytolysis with EL4 target cells (H-2b), while both the primarily sensitized PH spleen cells and the secondarily sensitized normal spleen cells were significantly cross-reactive against the third party EL4 target cells. Adherent PH spleen cells appear to be responsible for this augmented cytolytic capacity since their coculture with normal nonadherent responder spleen cells increased control cytolysis by approximately 30%. These studied demonstrate that, following 50% partial hepatectomy, there is an immediate and sustained increase in the allospecific cytolytic response.

Reversible changes in tumor growth and metastatic behavior induced by immune pressure

Prolonged exposure to host immunity was studied for its effect on several characteristics of a cloned 3-methylcholanthrene-induced fibrosarcoma. One million cells of a clone 10-O were injected subcutaneously into normal C3H/HeJ mice (clone 10-N) or tumor-immune mice (clone 10-I). After 10 passages in immune mice, 1 X 10(6) cells from 10-I tumor were transferred back into normal mice (clone 10-R). After 5 to 10 additional in vivo passages, clone 10-O, 10-N, 10-I, and 10-R tumors were transplanted into normal mice and observed for tumor growth rate, tumorigenicity, antigen specificity, metastatic potential, and plating efficiency. Clone 10-I after 10 passages in immunized mice grew significantly more slowly than did 10-O or 10-N clones, required more tumor cells to cause 50% tumor incidence in normal mice (tumorigenicity), and completely lost its capacity to metastasize spontaneously or experimentally. The plating efficiency in vitro of 10-I was also less than that of 10-O or 10-N. All these changes reversed after 5 to 10 passages of 10-I clone back into normal mice (10-R). Although immune pressure induced qualitative antigenic changes, as demonstrated by a tumor-rejection assay, and resulted in no cross-reactivity with control tumor clones (antigen specificity), the degree of immune response to its autologous clone in immune mice (immunogenicity) remained constant. These results suggest that several unrelated characteristics of this clone 10 can be phenotypically changed during the same period by immune pressure.

Choice of lasers for laser angioplasty

Thrombi in test-tube, intraarterial thrombi and pig aorta wall were in vitro irradiated with continuous CO2 laser, short pulsal and ultrashort pulsal YAG laser (with pulse-width of 10 ns and 40 ps, respectively) and their double frequency laser and excimer laser with a wave-length of 308 nm and pulse-width of 20 ns. Their effect of vaporizing and ablating (photodecomposing) thrombi and their thermal injuring effect on adjacent tissues were compared and assessed in order to select optimal laser with little thermal injuring and more rapid vaporizing or ablating thrombi effect for laser angioplasty. The experimental results showed that excimer laser, ultrashort pulsal YAG laser and its double frequency laser, and double frequency laser of short pulsal YAG laser, with laser beam and blood vessel kept in a coaxial position, can effectively vaporize or ablate thrombi without thermal injury to vessel wall. So they may be used for laser angioplasty. Of them, especially, excimer laser and double frequency laser of ultrashort pulsal YAG laser have short wave-length and high peak power, and more effectively ablate thrombi than others, so they proved to be optimal lasers for laser angioplasty.

Incidence of unfused ossicles in the lumbar facet joints: CT, MR, and cryomicrotomy study

The incidence of unfused ossicles in the lumbar spine, in radiographic studies, is 0.7-1.5%. With a sledge cryomicrotome, we sectioned 273 lumbar facet joints in 38 adult cadavers and correlated the anatomic appearance of the joints with CT and magnetic resonance (MR) images. Ossicles were present in 13% of the cadavers and 2.6% of the facet joints and were demonstrated effectively by MR. The incidence of ossicles, which can be confused with fractures, in the facet joints is higher than previously reported.

[An experimental study of excimer laser angioplasty in vitro]

Intratube thrombus and in vitro intraarterial thrombus and isolated normal pig aortic wall were radiated by excimer laser with wavelength of 308 nm and pulse width of 20 ns. The single pulse energy and the numbers of pulses were varied at the constant beam size and pulse frequency and the results were studied by micrometer measurement and histological examination. The results show: (1) excimer laser can effectively ablate thrombus. With constant total energy (at the range from 10 to 50 J), the depth of vaporized thrombus was nonlinearly proportional to the single pulse energy. But with constant single pulse energy (at the range from 10-100m J), the depth of vaporized thrombus was in linear proportion to the numbers of pulses; (2) if coaxial position of laser beam with blood vessel was maintained, thrombus can be effectively vaporized without arterial wall damage; (3) the incision produced by excimer laser has microscopically precise edges: there is no evidence of thermal injury and adjacent tissue is unaffected. Our conclusion is that excimer laser can be used safely and effectively in angioplasty. It may be mainly by photochemical effect that excimer laser ablates organic tissue.

Criteria for classifying normal and degenerated lumbar intervertebral disks

The purpose of this study was to develop criteria for distinguishing normal and degenerated lumbar intervertebral disks. Cryomicrotome sections from and magnetic resonance images of 31 cadavers were reviewed. The immature nucleus pulposus, found up to age 2 years; the transitional nucleus pulposus, found in teenagers; and the adult nucleus pulposus were associated with an intact anulus fibrosus without tears except for small concentric or transverse tears in the periphery of the anulus fibrosus. Discoloration of the nucleus pulposus, diminishing disk height, and diminishing signal intensity were associated consistently with a radial tear of the anulus fibrosus. The severely degenerated nucleus pulposus was associated also with a radial tear or complete disruption of the anulus fibrosus. The results suggest that intervertebral disk normally progresses from the immature to the transitional to the adult nucleus pulposus. When a radial tear develops in the anulus there is shrinkage and disorganization of fibrocartilage in the nucleus pulposus and replacement of the disk by dense fibrous tissue and cystic spaces.

The effect of patient positioning on MR imaging of the internal auditory canal

Identification of individual cranial nerves and complete exclusion of tumor in the internal auditory canal may be difficult with MR, especially in imperfectly positioned patients. MR studies of the temporal bones in patients and in normal volunteers positioned non-rotated or canted were correlated with corresponding cryomicrotomic sections. Especially in axial images, oblique sectioning of cranial nerves VII and VIII may cause difficulty in identifying individual nerves. A combination of axial and coronal short TR and TE images can be used to confidently exclude intracanalicular tumor in most cases.

Simultaneous ion-pair and partition liquid chromatography of acetaminophen, theophylline and salicylate with application to 500 toxicologic specimens

Acetaminophen (A), salicylate (S), and theophylline (T) are three common pharmaceutical agents involved in drug overdose for which determinations of serum drug concentrations play a pivotal role in clinical management. All three must be included in overdose screening, but often separate methods must be used. By combining reverse phase high performance liquid chromatography (HPLC) for A and T with ion-pair techniques for S, all three drugs can be chromatographed and quantitated simultaneously. A water-soluble ion-pair of S and 2-amino-2-(hydroxy-methyl)-1,3-propanediol eluted in a mobile phase of 4% acetonitrile and 12% acetic acid in water. Relative retention times for A, T and S were 0.41, 0.57 and 1.75 with an internal standard of 8-chlorotheophylline. Validation studies demonstrated recoveries of 88-104%, intraasay precisions of 2.1-6.6%, interassay precision of 3.8-8.0%, detection limits and linearity ranges of 2-200 mg/l for A and T and 10-1,000 for S. Seventy-two drugs were tested for interference. Accuracy studies showed no significant biases when compared to other methods. The method is convenient for toxicologic screening or therapeutic drug monitoring. In 576 consecutive serum specimens submitted for general toxicologic screening, 7.3% were positive for A, 5.2% for S, and 1.7% for T. Only 1.7% had critical concentrations indicating intoxication.

Substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines as potential inhibitors of H+/K+ ATPase

A series of substituted 2-[(2-benzimidazolylsulfinyl)methyl]anilines were synthesized as potential inhibitors of the acid secretory enzyme H+/K+ ATPase. Substitutions on the aniline nitrogen atom resulted in potent enzyme inhibition in vitro but weak activity in gastric fistula dogs. Electron-donating substituents on the aniline ring enhanced in vitro and in vivo potency relative to the unsubstituted analogue. The potency showed a correlation to the calculated pKa of the aniline nitrogen atom. Substitutions on the aniline and benzimidazole rings did not further enhance potency. Di- and trisubstituted aniline derivatives were potent inhibitors of the enzyme system. The preferred combination of substituents were a methoxy group on the benzimidazole ring and a single alkyl group on the aniline ring. One such compound, 76, was an effective inhibitor of acid secretion in the dog and was selected for further pharmacological study.

Response of spinach and kidney bean plants to nitrogen dioxide

Different responses of spinach and kidney bean plants to various concentrations of NO(2) in the light and in the dark were shown. Spinach is more resistant than NO(2) than kidney bean. It is not only due to its greater tolerance to NO(2)(-) accumulated in leaves, but also to its stronger ability to metabolize NO(2)(-). The injury of spinach induced by the exposure to high concentration NO(2) in the light was not caused by the accumulation of NO(2)(-), but concerned the large amount of accumulated NH(3). The primary causes of NH(3) accumulation were that the activity of nitrite reductase was not affected by the fumigation on the one hand, and the activities of glutamine synthetase and glutamate synthase were inhibited on the other.

Reversal of ischemic liver failure by intrasplenic liver cell transplantation

A model of ischemic hepatic failure in Sprague-Dawley rats (SD) with 100% mortality has been developed by one-hour occlusion of the right portal vein and hepatic artery followed by left 70% hepatectomy. The intrasplenic injection of 40 x 10(6) syngeneic adult or three-day neonatal single liver cell suspensions decreased the mortality from 100% to 50% and 36%, respectively. Mortality decreased with increasing time from the intrasplenic injection of neonatal liver cells to the time of acute hepatic ischemia. Mortality also decreased with increasing interval between hepatic ischemia and removal of the transplanted liver cells by splenectomy. Intrasplenic injection of graded doses of neonatal liver cells decreased mortality from 75% at a dose of 10 x 10(6) cells, to 36% at 160 x 10(6) cells. Treatment of neonatal liver cells with metabolic inhibitors did not significantly affect their ability to reverse acute hepatic ischemia.

Computed tomography and magnetic resonance imaging of the orbital apex

This article describes the CT and MR appearance of the orbital apex and masses in this region. The sectional anatomy by axial, coronal, and sagittal planes as well as the thin-layer technique used to accomplish this is detailed first. Then the application of these techniques to the presence of tumors is illustrated and discussed.

Endogenous forms of fibrinogen in Hep G2 cells

The three polypeptide chains of fibrinogen, A alpha, B beta and gamma chain, are synthesized on separate polysomes. Fully formed fibrinogen is a six chain, disulfide-linked, dimeric molecule with a molecular weight of 340kDa. Previous pulse-chase studies with L-35 S methionine using the human hepatocellular carcinoma cell line, Hep-G2, showed that the three chains are not immediately disulfide-linked and that there exist intermediate precursors as well as pools of A alpha and gamma chains (J. Biol. Chem. 259, 10574-10581, 1984). In this study the endogenous levels of fibrinogen and its precursors are measured by two different methods; pulse and steady-state labelling with L-35 S-methionine and immunoblotting. In Hep-G2 cells intracellular fibrinogen-related antigen is primarily (30-53%) composed of an A alpha-gamma complex and, to a smaller degree, of fully-formed fibrinogen (13-33%). Furthermore, the Hep G2 cell also contains endogenous pools of free gamma chain (11-26%). Other fibrinogen precursors (namely, the B beta-A alpha, B beta-gamma complexes as well as the fibrinogen half-molecule) do not appear to accumulate intracellularly. Most, if not all, of these precursors occur as isoforms but this heterogeneity is not due to varying degrees of glycosylation. In all the intracellular fibrinogen forms identified thus far, free sulfhydryl groups, detected by 14C-iodoacetamide incorporation, occur only in the A alpha-gamma complex and the free gamma chains.