Head-direction cells in the rat posterior cortex. II. Contributions of visual and ideothetic information to the directional firing

This study investigated the effects of visual and ideothetic cues on the spatial tuning of head-direction (HD) cells recorded in the rat posterior cortices. Extracellular, single unit responses were recorded from animals performing each of two different tasks, a spatial working memory task on a radial-arm maze and a passive rotation task on a modified "lazy Susan" platform. The influence of visual cues was assessed by manipulating the position of one white and three black cue-cards placed around the maze. We found three major categories of HD cells based on their response to cue manipulations in the maze tasks. Type A cells (10/41) rotated their preferred directions along with the rotation of the cues. The majority (type B, 25/41) of the HD cells were unaffected by the rotation of visual cues, maintaining their established preferred direction. Type C cells (6/41) showed complex responses to cue rotation, with the preferred direction reflecting either a combination of both type A and type B responses or an unpredictable response. The results indicate that the internal representation of directionality can be calibrated by visual cues and that some mnemonic processes may have been involved in the registration of the previous cue locations. Eleven cells were tested in both the maze task and the passive rotation task. Most (9/11) showed a significant directionality in the former task, but showed either no or weak directionality in the latter task, suggesting that movement-related ideothetic cues may be used in supporting the directional firing of these cells. Only two cells showed significant directionality in both tasks. Their established preferred directions did not rotate along with the cues in the maze task, but did rotate with the cues in the passive rotation task. We conclude that the dynamic aspect of the directional tuning in these cortical HD cells may represent on-line calibration of an angular coordinate representation.

Experimental transfer of Paragonimus westermani from rodents to rodents following subcutaneous and intraperitoneal routes

In order to investigate the experimental transfer of Paragonimus westermani from rodents to rodents following subcutaneous and intraperitoneal routes, 13 rats and 23 mice were inoculated with a total of 115 (1 mature and 114 immature) worms of P. westermani subcutaneously and intraperitoneally. The age of worms before transfer was 25-193 days. The transfer was performed immediately after worm collection from rodents which were killed at various intervals from 4 to 144 days after infection. The location, development and size of worms were recorded. An infection rate of 58% (or 21/36) was demonstrated in rodents after experimental transfer of P. westermani by intraperitoneal and subcutaneous routes. Twenty-seven worms were recovered, giving a worm recovery rate of 23.5%. The rate was significantly higher by the subcutaneous route (34.8%) than by the intraperitoneal route (20.7%) but no difference was found between mice (23.9%) and rats (23.0%). The sizes of worms in the abdominal cavity, pleural cavity and thoracic muscles of mice, and in the leg muscles of rats were much less than in the pleural cavity and lung cysts of rats. A mature worm (7 x 5 mm) and numerous eggs were found in the uterus and pleural cavity of one rat. It is evidence that these rodents are unfavourable definitive hosts of P. westermani, because the worm size, infectivity, maturation and egg production are usually very low. However, the worms are usually widely distributed in their rodent hosts and remain small in size for a long period. Therefore, these rodents are good paratenic hosts for P. westermani and can play an important role in infecting cats and dogs with P. westermani in the laboratory.

Laparoscopic Meckel's diverticulectomy in infants: report of three cases

Three infants younger than 2 years presented with episodic bloody-to-tarry stool of moderate amount. Two of them were diagnosed to have Meckel's diverticulum because of a positive 99mTc pertechnetate scan. Although the third infant had two negative radionuclide scans within 3 months, Meckel's diverticulum was still suspected by exclusion studies. All three infants underwent laparoscopic surgery. At laparoscopy, a Meckel's diverticulum was identified in all. Besides, an ileoileo intussusception just proximal to the diverticulum was also found in one patient. Reduction of the intussusception and diverticulectomy were performed successfully by laparoscopic procedure. Compared with conventional laparotomy, this procedure has the advantages of direct preoperative visual confirmation of the diagnosis, less traumatic access, much shorter recovery period and perhaps fewer intraoperative and postoperative complications. And thus, laparoscopic surgery has the potential of becoming regular treatment for symptomatic Meckel's diverticulum of infants.

Enflurane inhibits the function of mouse and human brain phosphatidylinositol-linked acetylcholine and serotonin receptors expressed in Xenopus oocytes

Modulation of the inositol 1,4,5-trisphosphate (IP3)-mediated signal transduction pathway by the inhalational anesthetic enflurane was studied in Xenopus oocytes expressing mouse and human cortical mRNA. We found that enflurane significantly inhibited ion currents activated by m1 muscarinic and 5-hydroxytryptamine (5-HT)1c receptors. This inhibition was dependent upon the concentration of acetylcholine or 5-HT, with large inhibition (80-89%) of low concentrations and small inhibition (8-44%) of high concentrations of acetylcholine and 5-HT. Similar effects were found with either mouse or human receptors. To investigate the mechanism of enflurane action, ion currents induced by intracellular injection of guanosine 5'-(3-O-thio)triphosphate and IP3 were examined. Enflurane strongly suppressed the guanosine 5'-(3-O-thio)triphosphate-activated current but not the IP3-activated current. These results suggest that an inhalational anesthetic can disrupt the function of mouse and human brain phosphatidylinositol-linked receptors by selectively inhibiting the guanine nucleotide-binding protein activity.

Experimental infection of Paragonimus westermani in mice and rats

To determine the infectivity and maturity of metacercariae of Paragonimus westermani after keeping at low temperature for a long period, 45 mice and 45 rats were each infected with 20 metacercariae which were kept at 4 degrees C for 8 to 234 days. The worm recovery in mice increased with age of worm and reached a peak of 32% at 41-50 days and then decreased with age. The rate in rats first decreased to a lowest point of 6% at 71-100 days and then increased with age. In 42 infected mice and 41 infected rats, 187 immature worms (183 tiny and 4 juvenile ones) and 190 worms (164 tiny, 19 juvenile and 7 mature ones) were recovered respectively. Two worm cysts with eggs only and 8 empty worm cysts were also found in the rats. In addition, the frozen metacercariae can still develop to mature worms in SD rats.

Molecular determinants of general anesthetic action: role of GABAA receptor structure

Using receptors expressed from mouse brain mRNA in Xenopus oocytes, we found that enhancement of type A gamma-aminobutyric acid (GABAA) receptor-gated Cl- channel response is a common action of structurally diverse anesthetics, suggesting that the GABAA receptor plays an important role in anesthesia. To determine if GABAA receptor subunit composition influences actions of anesthetics, we expressed subunit cRNAs in Xenopus oocytes and measured effects of enflurane on GABA-activated Cl- currents. Potentiation of GABA-activated currents by enflurane was dependent on the composition of GABAA receptor protein subunits; the order of sensitivity was alpha 1 beta 1 > alpha 1 beta 1 gamma 2S = alpha 1 beta 1 gamma 2L > total mRNA. The results suggest that anesthetics with simple structures may act on the GABAA receptor protein complex to modulate the Cl- channel activity and provide a molecular explanation for the synergistic clinical interactions between benzodiazepines and general anesthetics.

[Choledochal cyst associated with dominant dorsal duct syndrome: report of two cases]

Two cases with choledochal cysts associated with dominant dorsal ducts were reported. The first patient, a male infant, presented with abdominal distention and vomiting for two days at the age of four months. The second patient, nine month-old male infant, presented with fever for one day, irritability, post-prandial vomiting and preference for lying in a left lateral decubitus position. Both cases were operated under the impression of choledochal cysts, and were found by intraoperative cholangiopancreatography to have dominant dorsal ducts. These two cases and the literature concerning choledochal cyst associated with dominant dorsal duct are reviewed.

Enflurane inhibits NMDA, AMPA, and kainate-induced currents in Xenopus oocytes expressing mouse and human brain mRNA

Effects of enflurane, an inhalational anesthetic, on NMDA, AMPA, and kainate-gated currents were examined in Xenopus laevis oocytes expressing mouse or human brain mRNA. In oocytes expressing mouse mRNA, enflurane at an anesthetic concentration (1.8 mM) inhibited the NMDA-, AMPA-, and kainate-induced currents by 29-40%, 30-33%, and 20-27%, respectively, suggesting that all three glutamate ionotropic receptors are susceptible to suppression by inhalational anesthetics. Furthermore, inhibition by enflurane was independent of the concentrations of the agonists (NMDA, AMPA, and kainate) or the NMDA-coagonist (glycine). This suggests that enflurane inhibition does not result from a competitive interaction at glutamate or glycine binding sites. Enflurane also suppressed the oscillation and apparent desensitization of NMDA currents, suggesting an inhibition of Ca2+ influx through the NMDA channel. In oocytes expressing human brain mRNA, only kainate produced observable currents. Kainate currents of human channels were smaller in size than those of the mouse; however, the kainate concentration-response curve and percent inhibition (27-29%) by enflurane were similar for mice and humans. The results suggest that human and mouse kainate receptors have similar pharmacological characteristics.

Fifteen-hour continuous esophageal pH monitoring: influence of position on gastroesophageal reflux among asymptomatic babies

Using continuous esophageal pH monitoring, we examined 40 asymptomatic babies to evaluate the influence of different positions (prone, supine, right and left side lying position) on gastroesophageal reflux (GER). Several parameters including percent of time with a pH < 4, numbers of reflux episode, numbers of reflux episode lasting more than 5 min, average duration of longest reflux and average pH were studied. All babies were born fullterm and were 1 to 14 days old (average: 4 days). Male to female ratio was 1.7:1. For all parameters, except for average pH, we obtained more favorable results in prone position (p < 0.05). Continuous esophageal pH monitor is a suitable technique to evaluate GER under physiologic circumstances.

General anesthetics potentiate gamma-aminobutyric acid actions on gamma-aminobutyric acidA receptors expressed by Xenopus oocytes: lack of involvement of intracellular calcium

Potentiation of the gamma-aminobutyric acid (GABAA) receptor-gated Cl- channel response has been suggested to be a primary action of some anesthetic agents. We asked whether the GABAA receptor is a target site common for general anesthetics that are chemically and structurally diverse. This hypothesis was tested in Xenopus oocytes expressing mouse cortical mRNA, and GABA-activated Cl- currents were measured using two-electrode voltage clamping. General anesthetics, including inhalational (halothane, diethylether, enflurane and isoflurane), i.v. (3 alpha-hydroxy-5 alpha-dihydroprogesterone, ketamine and propofol) and alcohol (pentanol) anesthetics, enhanced GABA-induced currents by 56 to 1089% at concentrations that were clinically relevant. The results suggest that potentiation of the GABAA receptor/channel response may be a common action for anesthetic agents. Moreover, anesthetic effects were dependent on GABA concentrations; the enhancement was marked with low GABA concentrations and was exponentially decreased as the GABA concentration increased. Also, anesthetic effects were dependent on anesthetic concentrations. The apparent EC50 of halothane was found to be similar to the anesthetic ED50. We also investigated the role of intracellular Ca++ in mediating anesthetic enhancement of the GABA current. We found that intracellular injection of the Ca++ chelator, EGTA, did not change the enhancement by anesthetics. In addition, these anesthetics alone did not produce significant currents, suggesting that the Ca(++)-dependent Cl- current was not activated by these anesthetics per se. Thus, we found that diverse anesthetics potentiate GABA-induced Cl- currents, but this action is not mediated by a release of intracellular Ca++.

Synthesis and transport of GAP-43 in entorhinal cortex neurons and perforant pathway during lesion-induced sprouting and reactive synaptogenesis

Metabolic labeling and quantitative 2D gel autoradiography were used to assess changes in the synthesis and transport of GAP-43 in entorhinal cortex (EC) neurons and perforant pathway during lesion-induced sprouting and reactive synaptogenesis. In normal adult rats, there is a high constitutive level of GAP-43 synthesis and transport in EC neurons projecting to the hippocampus. Following unilateral EC lesions, there is a 2-fold (100%) increase in the transport of newly synthesized GAP-43 to the contralateral or 'sprouting' hippocampus. The timing of this upregulation (between 6 and 15 days) suggests that changes in GAP-43 expression occur in response to the growth of presynaptic terminals during sprouting.

Analysis and clinical correlates of the 14 and 6 Hz positive electroencephalographic spikes in Chinese children

From January 1987 to March 1991, electroencephalographic (EEG) analysis and clinical correlates of the 14 and 6 Hz positive spikes were studied retrospectively in 2,026 Chinese patients, ranging in age from 1 to 18 years. All of them were the first-evaluation patients of Pediatric Neurology Clinics, National Taiwan University Hospital, each had had through EEG examinations (including waking and natural sleep records) and detailed medical records. The major findings of the present study are: (1) The overall incidence of the 14 and 6 Hz positive spikes in the series was 2.52% (51/2,026), and that in the age subgroup 1-5 years was significantly lower than those in the subgroups 6-10 years (p less than 0.0001) and 11-15 years (p less than 0.01). (2) 38 out of 51 cases (74.5%) with 14 and 6 Hz positive spikes presented normal EEG background activity. (3) 7 out of 51 cases (13.7%) had coincided negative spikes in frontal areas, and 12 out of 51 cases (23.5%) were associated with other focal or generalized paroxysmal discharges. (4) From the analysis of the clinical manifestations in the 51 cases with the 14 and 6 Hz positive spikes, the episodic attacks of headache, abdominal pain or other autonomic symptoms were most common (49%, 25/51 cases). Of the 25 cases, 19 cases (37.2%, 19/51 cases) were finally diagnosed as autonomic seizure or abdominal epilepsy and 3 cases were diagnosed as migraine. 3 of 10 cases with convulsive seizure or complex partial seizure were associated with autonomic symptom. (5) The etiology in 36 out of 51 cases (70.6%) remained unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

The Rett and Rett-like syndromes: a broad concept

Eight patients who satisfied the following three criteria: 1) autistic behavior, 2) mental retardation and 3) stereotypic hand movements were evaluated. Four patients fulfilled the diagnostic criteria for the Rett syndrome developed by representatives of the International Rett Syndrome Association and the Center for Disease Control, Atlanta, USA. The other four Rett-like patients were atypical in the sense that the manifestations were incomplete or psychomotor development throughout the first 6 months of life was abnormal or the disease was heralded by infantile spasms with transient stereotypic hand movements or the baby was born with congenital microcephaly. All eight patients were girls. No laboratory test result specific for the Rett syndrome or Rett-like syndrome was obtained.

Analysis of a splice acceptor site mutation which produces multiple splicing abnormalities in the human argininosuccinate synthetase locus

The cloned argininosuccinate synthetase gene from a citrullinemia patient's fibroblast cell line revealed a single base substitution (G to C) within the splice acceptor site of the last intron. The mutation abolished normal RNA splicing, and, by cDNA analysis, three abnormal splicing pathways were demonstrated. The major pathway involved the activation of a cryptic acceptor site in the last exon that resulted in a deletion of seven nucleotides in the mature RNA. Another pathway involved a downstream cryptic acceptor site, that is 388 nucleotides downstream from the first cryptic site. Northern blot analysis showed that this second cryptic site is present on the minor 2.7-kilobase mRNA, but not on the major species of argininosuccinate synthetase mRNA, which is 1.7-kilobases in length. Using this aberrant cDNA as a probe, the cDNA of the 2.7-kilobase mRNA was isolated and studied. Sequence analysis suggests that this species of RNA is the one that bypasses the polyadenylation signal employed by the 1.7-kilobase RNA. Since both transcripts encounter the same translation termination codon, both RNAs should encode identical protein. Furthermore, a tract of 22 repeats of d(CA).(GT) is found at the 3' end of the gene and this repeat sequence is present on the 2.7-kilobase RNA. The third pathway of the abnormal splicing revealed a rare class of transcript that has the last intron retained in the mature RNA. This study shows that in human the intron inclusion can occur through a naturally occurring point mutation. All these abnormally spliced RNAs resulted in a protein reading frame shift.

Epilepsia partialis continua (Kojewnikow's syndrome): report of one case

We describe a 12-year-old boy with EPC (Epilepsia Partialis Continua) who showed well localized myoclonic jerks in the left toes continuing for more than 19 months. Preceding partial clonic or tonic convulsions of the left leg or body were initially noted. Neurological examination disclosed mild muscle weakness of the left leg. During the course, neither mental deterioration nor progressive evolution was noted. Since the EEG revealed well defined midline central spike focus which represent the sensorimotor area of left leg and foot, we postulate that the pathophysiological mechanism of the EPC may be evoked by the focal epileptogenic activation of the motor cortex. EEG-EMG polygraphy proved the well localized myoclonic action potential volleys in the M. extensor hallucis longus of the left great toe. According to the clinical and electrophysiological findings, we classified our case into the group I of Bancaud's definition but failed to find out any demonstrable brain lesion throughout brain CT, MRI and angiography. Neurosurgical intervention is not practical for our case, and medical treatment gave somewhat improvement.

Persistence of neurochemical changes in dopamine systems after repeated cocaine administration

The purpose of this study was to test whether persistent changes consistent with behavioral sensitization occur in dopamine (DA) uptake, release or receptors following repeated cocaine administration. Our neurochemical experiments focused primarily on the striatum; however, quantitative autoradiography was used to measure D-1 and D-2 DA receptors in both cell body and terminal regions of the nigrostriatal and mesolimbic dopaminergic pathways. After receiving eight once-daily injections of cocaine (10 mg/kg, i.p.), rats remained behaviorally sensitized for 1 week. This repeated treatment with cocaine induced two changes consistent with increased dopaminergic transmission. Postsynaptic D-2 DA receptors were selectively increased in nucleus accumbens one day after termination of the repeated cocaine administration; however, these receptors returned to control levels one week after cocaine administration had been terminated. In contrast, amphetamine-stimulated [3H] DA release from striatal slices was increased in rats receiving repeated cocaine injections, but this increase was not apparent until 1 week after the drug administration had been terminated. While neither of these two changes is sufficient to explain cocaine-induced behavioral sensitization, both are consistent with increased dopaminergic responsiveness and may contribute to sensitization.

Hypothalamic monoamines and their metabolites in the deermouse, Peromyscus maniculatus, during daily torpor

Deermice, subjected to food rationing, an ambient temperature below thermal neutrality and short photoperiod, were sacrificed in euthermia or during daily torpor. Hypothalamic monoamine and metabolite levels were quantified by HPLC with electrochemical detection. Significant elevations in the levels (pg/microgram protein) of dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid were noted in the torpid animals. The concentrations of norepinephrine and serotonin displayed no significant alterations between the euthermic and torpid states. However, the serotonin metabolite, 5-hydroxyindole-3-acetic acid, was elevated by almost 300%. These data suggest that an increase in activity of the hypothalamic serotonergic and dopaminergic systems occurs during daily torpor in the deermouse.

Comparison of spatial and temporal characteristics of neuronal activity in sequential stages of hippocampal processing

The activity of individual pyramidal cells in the CA1 and CA3 subfields of the rodent hippocampus exhibits a remarkable selectivity for specific locations and orientations of the rat within spatially-extended environments. These cells exhibit high rates of activity when the animal is present within restricted regions of space, referred to as place fields, and are extremely quiet when it is elsewhere. Although this phenomenon has been well studied in the CA fields of the hippocampus, relatively little is known about the spatial and temporal firing characteristics either of the entorhinal cortical inputs to the hippocampus, or of the subicular recipients of the output of hippocampal place cells. We report here on a comparison of spatial and temporal discharge characteristics among entorhinal cortex, CA3 and CA1, and the subiculum. CA3 complex spike cells were significantly more spatially specific than their CA1 counterparts. Neither entorhinal cortex nor subiculum exhibited the highly localized patterns of spatial firing observed in the CA fields. In addition, average discharge rates in these areas were substantially higher. However, particularly in subiculum, there was evidence for spatially consistent, but dispersed, firing in some cells, suggestive of the convergence of a number of CA1 place cells. The patterns observed are not consistent with the hypothesis that spatial selectivity is progressively refined at the various levels of hippocampal processing. Rather, hippocampal output appears to be expressed as a much more highly distributed spatial code than activity within the hippocampus proper. We suggest that the sparse coding used within the hippocampus itself represents a mechanism for increasing the storage capacity of a network whose function is to form associations rapidly.

An unexpected pH effect on the stability of moexipril lyophilized powder

Because of the limited stability of moexipril (RS-10085; 1) in aqueous solution, lyophilized parenteral formulations were evaluated as a function of pH in this study. In general, the lyophilized powder of 1 showed about two orders of magnitude less reactivity at 50 degree C than in aqueous solution at pH values below 3 or above 6. At pH 5.1, however, the lyophilized powder had maximum reactivity, with the rate actually comparable to that observed in aqueous solution. When the distribution of the two major products, diketopiperazine (DKP) 2 and ester hydrolysis analogue 3, was compared to the observed kinetics as a function of pH, it was clear that removal of water via lyophilization suppressed the spontaneous k1 cyclization process, the spontaneous k3 hydrolysis process, and the specific base-catalyzed k4 hydrolysis process. The overall spontaneous k2 cyclization process, however, was not affected by lyophilization. The latter result is accounted for by the increased equilibrium constant for the formation of the tetrahedral intermediate, To, as a result of lyophilization. This study demonstrates that stability data in solution can not be used for predicting the stability of moexipril in lyophilized powder form.

Preclinical development and characterization of an intravenous dosage form for the ACE inhibitor RS-10029

Preclinical development of an intravenous dosage form for the ACE inhibitor RS-10029 involved the formulation and characterization of the drug's chemical/physical stability in two prototype formulations (injectable solution and lyophilized powder). Included in these studies were quantitative evaluations of various processing and administration parameters (membrane qualification, terminal sterilization, compatibility/delivery of the drug with typical infusion fluids and administration sets) on finished product integrity and quality. Analytical methodology used in these studies consisted primarily of a stability specific HPLC assay and a light obscuration based sensor (HIAC) for particulate matter analysis. Results of these studies indicate that the drug is relatively stable at ambient temperature and under accelerated storage conditions (predicted T90 at 25 degrees C greater than 2 yr, and T90 at 50 degrees C greater than 2 mo). However, the ability of the product to withstand a full terminal sterilization cycle is limited, and therefore other approaches toward sterile processing were examined. With regard to the stability and compatibility of the drug in a variety of fluids and devices there appears to be no overt limitations in its use for either bolus or infusion delivery.

Hepatitis B virus transcript produced by RNA splicing

A new hepatitis B virus (HBV) transcript of about 2.2 kilobases was identified in HBV DNA-transfected human hepatoma cells. The 5' terminus of this viral RNA appears to map at one or more of the precore initiation sites, contains a deletion of 1,223 bases corresponding to the last codon of the core gene to the middle of the surface antigen gene, and terminates at the 3' polyadenylation site used by the other known HBV RNAs. The junction region of the deleted sequences showed the conserved splice donor and acceptor GT-AG sequences. Moreover, when a mutant HBV DNA in which the splice acceptor site was changed from AG to CG was transfected into human hepatoma cells, no 2.2-kilobase RNA was detected, further suggesting that this RNA represents a spliced transcript. The core gene, although an amino acid shorter, still encoded a functional viral core protein in complementation experiments. Sequence analysis of the cDNA of the 2.2-kilobase RNA suggests that this transcript can potentially encode a new protein that comprises the reverse transcriptase domain of HBV. However, genetic analysis using a transient DNA transfection system suggests that the gene product(s) of this transcript is not essential for viral replication. The function of this transcript remains to be studied.

Analysis of serotonin, dopamine and their metabolites in the caudate putamen, the suprachiasmatic nucleus and the median raphe nucleus of euthermic and torpid deermice, Peromyscus maniculatus

Deermice, subjected to food rationing and low ambient temperature, were sacrificed in normothermia or during daily torpor. Levels of monoamines and their metabolites in the caudate putamen (CPN), the suprachiasmatic nuclear area (SCN), and the median raphe nucleus (MRN) were quantified through the use of HPLC with electrochemical detection. Significant elevations in levels (pg/mg protein) of the serotonin (5-HT) metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) were noted in torpid individuals in all nuclei examined. The dopamine (DA) metabolite, homovanillic acid (HVA) was significantly elevated in the CPN and MRN of torpid individuals. Moreover, a significant increase in the HVA to DA ratio was also noted in the CPN and the MRN. In the SCN, the concentrations of 5-hydroxytryptophan (5-HTP), 5-HT, DA and 3,4-dihydroxyphenylacetic acid (DOPAC) were also increased significantly during torpor. These significant elevations suggest that an increase in the activity of the serotonergic and dopaminergic systems occurs in these nuclei during daily torpor in the deermouse.

Study of restriction fragment length polymorphisms at the human phenylalanine hydroxylase locus and evaluation of its potential application in prenatal diagnosis of phenylketonuria in Chinese

Using a human phenylalanine hydroxylase cDNA probe, the restriction fragment length polymorphisms at the human phenylalanine hydroxylase locus have been determined with the restriction enzymes BglII, PvuII, EcoRI + BamHI, MspI, XmnI, HindIII and EcoRV. The frequency of the observed heterozygosity of the restriction site polymorphisms at this locus in a Chinese population is approximately 54%, which is significantly lower than that in Caucasians. No DNA rearrangement or deletion of the phenylalanine hydroxylase locus was detected among mutant phenylalanine hydroxylase genes in seven Chinese classical phenylketonuria (PKU) families. Haplotype analysis of these seven families revealed that the mutant alleles belonged to five different haplotypes, i.e. haplotype 4, 11 and three unreported haplotypes. The majority of normal and mutant phenylalanine hydroxylase genes are confined to hyplotype 4. These results indicate that approximately 42% of Chinese PKU families are informative for prenatal diagnosis of PKU when eight restriction sites linked to the phenylalanine hydroxylase locus are examined.

Analysis of hepatitis B virus transcripts in infected human livers

The hepatitis B virus transcripts in human hepatoma and its adjacent nontumorous liver were examined with probes specific to hepatitis B virus surface antigen, core antigen, X region and pre-S region. The study shows that the patterns of hepatitis B virus transcripts for tumorous tissue and the counterpart in nontumorous liver differ. In most of the tissues examined, the surface antigen gene is transcribed. Most of these transcripts, besides having surface antigen sequences, also have an X region; some also include a pre-S region. The transcripts that hybridized to a core-specific probe were a pair of poly(A+) RNA, 3.5 and 2.2 kilobases in size, present in two of the nontumorous hepatocytes where the virus was actively replicating. The 3.5-kilobase transcript not only hybridized to the core probe, but was able to be hybridized to other hepatitis B virus subgenomic probes and might represent the RNA pregenome involving hepatitis B virus DNA replication. Whereas most of the transcripts hybridizable to hepatitis B virus probe are in the size range of 2.1 to 2.7 kilobases, some transcripts other than the pregenomic RNA appear to be greater than 3.2 kilobases in size and may represent the hybrid RNAs of viral and host sequences.

[Route and preparation of 5-Fu administration as preoperative adjuvant chemotherapy in rectal cancer. II. Morphologic, ultrastructural and histochemical changes of the cancer cells after intrarectal and intravenous 5-Fu administration]

From March 1981 to October 1985, 5-Fu was preoperatively given to 65 Dukes B and C rectal cancer patients (intrarectal suppository 40 and emulsion 20, intravenous 5). The results indicated that after intrarectal administration, marked changes and destruction of the cancer cells in morphology were observed in 40% of the resected rectal specimens for suppository and in 45% for emulsion; marked retrograde degeneration in ultrastructure was found in 47.5% for suppository and in 50% for emulsion; DNA synthesis was obviously reduced in 63% for suppository and in 75% for emulsion. It is suggested that the emulsion be a better preparation. No obvious changes or destruction in morphology and ultrastructure were observed in cancer cells treated by intravenous drip of high dose 5-Fu though leukopenia below 4000 was found in 2/5. However, it was 0/60 by rectal administration. This implies that the intrarectal route is more rational than the conventional intravenous route. This study presents an alternate supplementary treatment in addition to radiotherapy for the reduction of postoperative local recurrence of Dukes B and C rectal cancers.

Electrochemical evaluation of the interaction between ascorbic acid and the cardiotonic drug RS-82856

The solution phase interaction between ascorbic acid and the cardiotonic drug N-cyclohexyl-N-methyl-4(7-oxy 1,2,3,5-tetrahydroimidazol[2,1-b] quinazolin-2-one butyramide (RS-82856) was evaluated using a differential pulse voltammetric technique. Shifts in the peak potential of ascorbic acid to higher energy as well as decreases in peak current values were monitored as a function of RS-82856 concentration. The electrochemical data were obtained under conditions where both the drug and the ascorbic acid concentrations exhibited linear relationships with peak current values. The methodology was extended to the study of two other structurally related phosphodiesterase inhibitors cilostamide and anagrelide. The complexation of these drugs with ascorbic acid were also characterized by decreases in the diffusion currents of ascorbic acid as well as by anodic shifts in the peak potential. The significance of these observations may be related to the inhibition of cyclic nucleotide phosphodiesterase activity by both the drugs tested and the ascorbic acid.

Stability of ganciclovir sodium (DHPG sodium) in 5% dextrose or 0.9% sodium chloride injections

The stability of 9-[(1,3-dihydroxy-2-propoxymethyl]) guanine sodium (ganciclovir sodium, also known as DHPG sodium) in two infusion solutions was studied. Lyophilized ganciclovir sodium 500 mg was reconstituted with sterile water 10 mL to give a theoretical concentration of 50 mg/mL. After reconstitution, 6-mL aliquots of the solution were added to 100 mL of 0.9% sodium chloride injection or 5% dextrose injection in polyvinyl chloride i.v. bags. One sample was withdrawn from each of 10 bags of each solution and analyzed by high-performance liquid chromatography (HPLC). Thirty bags of each solution were then stored under each of the following conditions: at room temperature under laboratory light, at room temperature in the dark, and under refrigeration for up to five days. Single potency assays were performed by HPLC on each of three bags of solution at three and five days after initial dilution of the solutions. The solutions were visually inspected, and the pH of the solutions was measured. All solutions of ganciclovir were stable for at least five days under all storage conditions; mean ganciclovir concentrations did not drop below 98% of initial theoretical values throughout the storage period. No important changes in the pH of the solutions occurred during the study period. Under the conditions of this study, ganciclovir sodium is stable for up to five days when prepared in 5% dextrose injection or 0.9% sodium chloride injection.

Hepatitis B virus transcripts in a human hepatoma cell line, Hep 3B

Hep 3B, a human hepatoma cell line was examined for its RNA hybridizable to the hepatitis B virus sequence. Using probes that covered different regions of the hepatitis B virus genome, five species of RNA were observed of sizes 4.0, 3.3, 2.9, 2.6 and 2.2 kilobases. The RNAs covered surface antigen gene, pre-S and X regions. None of them had a core antigen sequence. RNA with a 4.0 kilobase size was the most abundant. Using S1 nuclease analysis, its 5' end of hepatitis B virus sequence was mapped at pre-S region and its 3' end of viral sequence was mapped at DR region.

Effects of intrahypothalamically administered norepinephrine, serotonin and bombesin on thermoregulation in the deermouse (Peromyscus maniculatus)

Norepinephrine, serotonin, and bombesin administered intrahypothalamically affected thermoregulation in the deermouse, Peromyscus maniculatus. At a Ta of 22 degrees C, doses of 3 micrograms and 6 micrograms of NE resulted in transient hypothermia (maximum drop of 1.6 +/- 1.0 degrees C and 4.3 +/- 2.3 degrees C, respectively). A 1.5 microgram dose of 5-HT induced a persistent hyperthermia (maximum increase of 1.8 +/- 0.8 degrees C) which persisted for more than 2 h. A 6 microgram dose of 5-HT did not produce any significant effects. At a Ta of 22 degrees C, doses of 1 ng and 10 ng of bombesin produced a transient hyperthermia (maximum increase of 1.8 +/- 0.3 degree C and 2.1 +/- 1.2 degrees C, respectively) immediately postinjection. At a Ta of 5 degrees C, a 1 ng dose of bombesin resulted in a prolonged hypothermia (maximum decrease of 2.0 +/- 0.4 degrees C), while a 10 ng dose of bombesin produced a hyperthermic response (maximum increase of 1.3 +/- 0.8 degree C) at 2 h postinjection.

Expression of c-myc gene in human hepatoma

The level of c-myc transcript was examined in liver samples from seven hepatoma patients. Transcripts were detected in all the normal liver parts examined; in contrast, in two hepatoma parts, there was a dramatic reduction in c-myc transcripts. The restriction enzyme pattern of c-myc gene appeared the same among samples. The data suggest that c-myc gene expression might not be required for the maintenance of the tumor state in human liver carcinogenesis.

Serodiagnosis of acute B hepatitis: comparison between a competitive binding radioimmunoassay and an enzyme linked immunosorbent assay for IgM antibody to hepatitis B core antigen

The standard radioimmunoassay for anti-HBc (CORAB) was modified for the differential detection of anti-HBc IgM by incorporation of a step in which anti-HBc IgG was preferentially absorbed by Staphylococcus aureus cells (Protein A). The ratio (R) of anti-HBc IgM to total anti-HBc was evaluated by computing the ratio of sample cpm's after and before protein A absorption. The R values of acute B hepatitis ranged from 0.9 to 2.1 (mean 1.3 +/- 0.3) while those of chronic HBsAg carriers ranged from 3.1 to 8.3 (mean 4.9 +/- 1.1). Adopting 2.1 as the upper limit of R value for acute B infection, this modified CORAB was shown to have excellent correlation with enzyme immunoassay, and to be capable of differentiating acute from persistent HBV infection in HBsAg positive patients, and discriminating acute B hepatitis from non-A, non-B hepatitis in HBsAg negative but anti-HBc positive acute hepatitis.

Haloacetonitrile excretion as thiocyanate and inhibition of dimethylnitrosamine demethylase: a proposed metabolic scheme

Haloacetonitriles, contaminants present in chlorinated drinking water, were administered orally to rats, and the urinary excretion of thiocyanate was measured as an index of cyanide release. The urinary excretion of thiocyanate accounted for 14.2% of the dose of monochloroacetonitrile; 7.7-12.8% of the dose of bromochloro-, dichloro-, and dibromoacetonitrile; and 2.25% of the dose of trichloroacetonitrile. The haloacetonitriles inhibited rat-liver microsomal dimethylnitrosamine (DMN) demethylase in an in vitro assay system. Dibromo- and bromochloroacetonitrile were the most potent inhibitors of DMN demethylase, with Ki = 3-4 X 10(-5) M; dichloro- and trichloroacetonitrile were the next most potent, with Ki = 2 X 10(-4) M; and monochloroacetonitrile was the least potent inhibitor, with Ki = 9 X 10(-2) M. Trichloroacetonitrile, but not dibromoacetonitrile, when administered orally inhibited hepatic DMN demethylase activity. The relative capacity of the haloacetonitriles to inhibit DMN demethylase and to be excreted as thiocyanate did not correlate.

Role of O6-methylation in the initiation of GGTase-positive foci

The ability of seven methylating agents to form 7-methylguanine and O6-methylguanine was compared to their ability to initiate carcinogenesis as measured by the initiation of GGTase-positive foci. The seven methylating agents studied were methyl-N-nitroso-p-toluenesulfonamide (diazald), dimethylhydrazine (DMH), dimethylnitrosamine (DMN), dimethylsulfate (DMS), methyl methanesulfonate (MMS), methyl-N-nitro-N-nitrosoguanidine (MNNG) and methyl-N-nitrosourea (MNU). The DNA methylation and initiation of GGTase-positive foci was determined in partial hepatectomized rats. The formation of foci was promoted by 500 ppm sodium phenobarbital in the drinking water. While six of the seven compounds (DMH, DMN, DMS, MMS, MNNG and MNU) produced 7-methylguanine, only the four compounds (DMH, DMN, MNNG and MNU) that produced O6-methylguanine initiated GGTase-positive foci. The extent of O6-methylguanine produced by the methylating agents did not correspond with their potency to initiate GGTase-positive foci. Therefore, the initiation of GGTase-positive foci required the formation of O6-methylguanine. However, some sequential event altered the quantitative relationship of O6-methylguanine formation to the incidence of GGTase-positive foci.

Clones from cultured, B16 mouse-melanoma cells resistant to wheat-germ agglutinin and with altered production of mucin-type glycoproteins

Several clones resistant to wheat-germ-agglutinin toxicity were isolated from B16 mouse-melanoma cells. The resistance may be explained in part by fewer binding sites for the agglutinin on the variant lines; the total, cellular sialic acid content appeared somewhat reduced. Analysis of cell glycoproteins indicated a decreased content of sialic acid in one glycoconjugate that binds to wheat-germ agglutinin and has O-linked oligosaccharides.

Trihalomethanes as initiators and promoters of carcinogenesis

Chloroform and other trihalomethanes are contaminants of drinking water that have been demonstrated to be carcinogenic in laboratory animals. Determination of the mechanism of carcinogenicity of chloroform is required so that the animal data can be extrapolated to estimate the human health hazard. The extent of the binding of chloroform to rat liver and kidney DNA was approximately 0.1% the level of binding found for dimethylnitrosamine. Neither chloroform nor bromoform, in contrast to diethylnitrosamine-initiated GGTase-positive foci in either intact or partial hepatectomized rats, promoted with phenobarbital. Tumor-promoting activity of chloroform was indicated by the slight significant increase, compared to untreated controls, in the incidence of GGTase-positive foci in rats initiated with diethylnitrosamine (DENA) followed by the administration of chloroform twice weekly for a total of 15 doses. In this study, rats administered only the DENA or the chloroform did not contain an increased incidence of GGTase-positive foci compared to untreated controls. However, the incidence of foci in the group that received DENA followed by chloroform was not statistically different from that in either the group that received only the DENA or only the chloroform. In conclusion, we were unable to demonstrate tumor-initiating activity for chloroform, and the tumor-promoting activity of chloroform indicated by our results requires further confirmation.

Efficient and aberration-free wavefront reconstruction from holograms illuminated at wavelengths differing from the forming wavelength

Recording materials producing higher efficiency, low absorption holograms are usually photosensitive only to blue and uv light. If a hologram is formed at a blue wavelength in such a material and is illuminated at a red wavelength, generally the reconstructed wavefront is aberrated, and the resolution of the image is reduced. A method of hologram formation is described that can alleviate this problem. In this method, a hologram H(1) is formed first at the red wavelength lambda(1) in a photographic emulsion. This hologram is then illuminated at the blue wavelength lambda(2) The diffracted wave from H(1) is used as the subject wave for forming the desired high efficiency hologram H(2). If certain requirements are met, illumination of H(2) at lambda(1) can produce an aberration-free reconstruction of the original subject wave. Experimental results of forming H(2) of a point source on dichromated gelatin film are presented. The hologram was formed at lambda(2) = 4800 A but could reconstruct an aberration-free wavefront at lambda(1) = 6328 A. The hologram had about 80% diffraction efficiency and essentially no absorption loss.

Write-read-erase in situ optical memory using thermoplastic holograms

A method of using a thermoplastic hologram array for a write-read-erase in situ optical memory is proposed. A model of the proposed memory consisting of an array of 3 x 3 holograms was constructed. The experimental results of the model demonstrated that (1) thermoplastic holograms can be organized into an array on a single glass plate with adequate thermal isolation, (2) the number of recording-erasure cycles of a thermoplastic hologram can be well over 100, and (3) because of the absence of Bragg diffraction from thermoplastic holograms, the input and the output planes of the memory can be conveniently separated without any imaging lens and mechanical movement. Photographs of some images obtained from one hologram of the model array are shown.

Hologram formation in hardened dichromated gelatin films

Hardened gelatin films sensitized with ammonium dichromate can be utilized to record high quality holograms. The maximum diffraction efficiency of the hologram approaches 90%. The light scattering from the hologram is so low that under ordinary light the hologram plate appears almost indistinguishable from a clear glass plate. Either a transmission or a reflection hologram can be recorded. Linear recording range of light amplitude is large. A practical method of preparing and processing the film is described, and the exposure characteristics are presented.

A method of hologram information reduction by spatial frequency sampling

A simple method of hologram information reduction is described. By means of a Fourier transform hologram of some particular size and form, a number of discrete bands of spatial frequencies from a subject is sampled and recorded. The total area of this hologram is so small that the sampled bands contain only the minimum information necessary for a satisfactory holographic image. This hologram is then reproduced in large numbers to form a mosaic of identical holograms, one adjacent to another and in identical orientations. This mosaic of holograms is made large enough to cover the entire field of view. The resulting wavefront reconstructed from such a mosaic produces a satisfactory holographic image. If the hologram information is so reduced as to allow the sacrifice of the vertical parallax in the image, a significant reduction can result from this method. Experiments have shown that a factor of 10(3) in the over-all information reduction is practical in some cases.

Experimental techniques in making multicolor white light reconstructed holograms

Because of the characteristics of the available white light sources, lasers and photographic emulsions, as well as the environmental condition of a laboratory, many practical problems are often encountered in making high quality multicolor holograms reconstructed in white light. The nature of the difficulties is discussed. Techniques useful to the solutions of these problems are presented, such as increasing the coherence length of a laser with little sacrifice in power, improving the signal-to-noise ratio in the reconstruction, controlling the shrinkage of the emulsion to eliminate color shift, and increasing the speed of Kodak 649F emulsion.