Syringin 4-O-beta-glucoside, a new phenylpropanoid glycoside, and costunolide, a nitric oxide synthase inhibitor, from the stem bark of Magnolia sieboldii

Syringin 4-O-beta-glucoside (1), a new phenylpropanoid glycoside, and costunolide (2) were isolated from the stem bark of Magnolia sieboldii. The structures were determined by spectroscopic and chemical methods. Costunolide (2) exhibited strong nitric oxide synthase inhibitory activity in the endotoxin-activated murine macrophage, J774.1.

The oxidative burst protects plants against pathogen attack: mechanism and role as an emergency signal for plant bio-defence--a review

Various aspects, mechanisms and functions of the oxidative burst with generation of O2- superoxide anions in plant cells, which is stimulated by active defence-inducing agents such as fungal infection or elicitor treatment, were reviewed mainly on the basis of experimental evidence obtained in a system of Solanaceae plants and Phytophthora spp. The oxidative burst may be due to an O(2-)generating NADPH oxidase in the plasma membrane, which is activated with combinations of cytosolic proteins, Ca2+, calmodulin and protein kinase, following stimulation by elicitor molecules. The oxidative burst may play the role of an internal emergency signal for induction of the metabolic cascade for active defence.

Effects of dietary supplementation of lipophilic fraction from Panax ginseng on cGMP and cAMP in rat platelets and on blood coagulation

We have studied the effect of dietary supplementation with 25 mg (0.0025% of the total diet) of a lipophilic fraction (LF) from Panax ginseng on rat platelet aggregation induced by collagen or thrombin, and on blood coagulation. When platelets prepared from 15% corn oil plus LF-administered rats (COLF) were stimulated by thrombin (0.1 units/ml) and collagen (100 micrograms/ml), the cGMP level was significantly increased as compared with those from 15% corn oil only-administered rats (CO). The levels of cAMP in COLF were decreased by thrombin, but was increased by collagen. Furthermore, the levels of both cGMP and cAMP were also increased by the exogenous addition of LF to thrombin- and collagen-stimulated platelets. These results mean that LF increases cGMP directly and cAMP indirectly, and thus inhibits thrombin- or collagen-induced rat platelet aggregation. Both the thrombin time (TT) and activated partial thromboplastin time (APTT) were prolonged more in citrated platelet-poor plasma from COLF than in that from CO. The level of lipids such as triglyceride, total cholesterol, high density lipoprotein-cholesterol and low density lipoprotein-cholesterol was decreased in serum from COLF more than in that of CO. Thus, these results suggest that dietary LF regulates the levels of cGMP and cAMP, and prolongs the time interval (TT, APTT) between the conversion of fibrinogen to fibrin. Accordingly, our data demonstrate that dietary LF has an antithrombotic effect in vivo.

A negative regulatory factor for the dark repression of Arabidopsis thaliana cab1 gene

A protein factor and its binding site involved in light-responsive gene expression of Arabidopsis thaliana cab1 were investigated. Mobility shift assays were performed to identify a nuclear protein factor and its binding sites on the cab1 promoter. For the binding assay, the Arabidopsis cab1 promoter was cleaved with endonucleases into small fragments (65-200 bp) and end-labeled with Klenow fragments. Nuclei were prepared from the light-grown plants and nuclear proteins were prepared by extracting the purified nuclei with 0.5 M ammonium sulfate. The binding site of the nuclear protein factor was scattered throughout the whole promoter region from the transcription start site to the far upstream region of the promoter. To identify the binding sites that are involved in the light responsiveness, mobility shift assays were performed between the cab1 promoter fragments and the nuclear extracts prepared from the 2 day dark-adapted sample. The mobility shift assay of the 65 bp (-318/ -254) fragment with nuclear extract from the dark-adapted sample showed an additional band, not seen with the light-grown sample. Because the new band was present only in the dark-adapted sample that repressed cab1 expression, it may represent a negative regulatory factor (NRF). The NRF was separable on a heparin-Sepharose column from the other factor present in both the light-grown and dark-adapted samples. The implications of the presence of the NRF have been discussed with respect to gene products of the photosignal transduction Arabidopsis mutants.

Hepatitis B and C virus, Clonorchis sinensis for the risk of liver cancer: a case-control study in Pusan, Korea

BACKGROUND

Liver cancer mortality in Korea is the highest in the world. Hepatitis B and C viruses (HBV, HCV) are known to be the major risk factors of hepatocellular carcinoma (HCC). Cholangiocarcinoma (CLG) accounts for more than 20% of liver cancer in the Pusan area. In Korea, the different roles of known risk factors in the development of HCC or CLG have not been adequately evaluated.

METHODS

Case-control studies involved 203 incident HCC cases, 406 controls matched to the HCC cases for age (+/- 4 years) and sex, and 41 CLG cases (the HCC controls were used). They were carried out from August 1990 to August 1993.

RESULTS

Relative risk (RR) of HBsAg (87.4; 95% confidence interval [CI]: 22.2-344.3) and RR of anti-HCV positivity (30.3; 95% CI: 6.1-150.6) were significant for the risk of HCC after adjustment for potentially confounding factors. In contrast, RR of Clonorchis sinensis in stool (2.7; 95% CI: 1.1-6.3) and RR of heavy drinking (4.6; 95% CI: 1.4-15.2) were significant for the risk of CLG. Transfusion history, acupuncture history, and cigarette smoking were not associated with the risk of HCC or CLG.

CONCLUSIONS

Strong evidence indicated that both HBV and HCV infection were independent risk factors for HCC. In contrast, C. sinensis in stools and heavy drinking were associated with the risk of CLG in Korea.

Tuberculous abscess in retromammary region: CT findings

PURPOSE

Our goal was to evaluate CT findings of tuberculous abscess in the retromammary region of the breast.

METHOD

Four patients with tuberculosis extending from the retromammary region to the pleura were examined by CT and the findings were evaluated. All cases were also examined with mammography and two cases were evaluated with sonography. Diagnosis was confirmed by acid-fast bacillus stain, culture, and histologic examination.

RESULTS

Mammography showed relatively smoothly marginated, round mass density in two cases, nodular density in one, and focal bulging of the pectoral wall in one. A sonogram demonstrated in two cases a fistulous connection from the heterogeneous, fluid-containing lesion with floating internal debris in the retromammary region to the thoracic cavity. In all four cases, CT showed relatively smoothly marginated, inhomogeneous, hypodense lesions with surrounding rims of the cold abscess type. A direct fistulous connection from the retromammary lesion through the thoracic wall into the pleura was seen in two cases. Destroyed rib fragments within the abscess were noted in two cases.

CONCLUSION

A tuberculous abscess in the retromammary region usually showed on CT a focal, smoothly marginated, inhomogeneous, hypodense lesion with a surrounding enhancing rim. A direct fistulous connection with the pleura or a destroyed rib fragment in the abscess as revealed by CT can be helpful in the differential diagnosis of other infectious types of retromammary abscess.

Evaluation of therapeutic regimens for the treatment of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is currently considered the most important exogenous factor in the genesis of gastritis and peptic ulcer disease. However, the optimum regimen for the eradication of H. pylori remains unclear. The purpose of this study was to evaluate the eradication rate of H. pylori, the side effects, and the patients' compliance with regard to various drug regimens. We also analyzed factors influencing the eradication of H. pylori. One hundred and eighty patients were included and divided into four groups: 42 patients (Group I) received tripotassium dicitrato bismuthate (240 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; 55 patients (Group 2) received omeprazole (20 mg b.i.d.) and amoxicillin (1000 mg b.i.d.) for 14 days; 36 patients (Group 3) were treated with omeprazole (20 mg b.i.d.), metronidazole (250 mg t.i.d.) and amoxicillin (500 mg t.i.d.) for 14 days; and 47 patients (Group 4) received omeprazole (20 mg q.d.) and amoxicillin (500 mg t.i.d.) for 14 days and then tripotassium dicitrato bismuthate (240 mg b.i.d.) and nizatidine (150 mg q.d.) for 14 days. The diagnosis of H. pylori was made by histology. The eradication of H. pylori was defined both by histology (H&E and Giemsa stain) and by rapid urease test (CLOR) showing negative for H. pylori 4 weeks after the completion of therapy. Of the 180 patients, 95 patients had non-ulcer dyspepsia, 40 patients had gastric ulcer and 45 patients had duodenal ulcer. The eradication rate of H. pylori was highest (89.3%) in Group 3, as compared with Group 1 (68.9%), Group 2 (65.4%), and Group 4 (48.9%). The eradication rate was significantly higher in Group 3 than in Groups 2 and 4 (p < 0.05). There was no significant difference in the eradication rate among clinical diagnosis, sex and age. But, in the conventional triple therapy (Group 1), the eradication rate was higher in male (78.6%) than in female (46.2%). The side effects in order, were nausea (22.1%), dizziness (19.5%), abdominal pain (11.6%) and diarrhea (97%), and there was no difference among the drug regimens. The compliance of the patients was good (more than 80% irrespective of drug regimen). On the basis of these findings, the side effects of the drugs seemed minimal, and the compliance of patients was good irrespective of the drug regimen. In conclusion, the triple therapy with omeprazole, metronidazole and amoxicillin was the most effective regimen and could be recommended for H. pylori eradication.

The functional relationships between hiatal hernia and reflux esophagitis

The purpose of this research was to investigate functional studies by which the hiatal hernia (HH) may be relevant to a reflux esophagitis (RE). Group I consisted of healthy controls who were endoscopically normal (n = 21). Group II consisted of patients with hiatal hernia but no reflux esophagitis (n = 8). Group III had patients with hiatal hernia with reflux esophagitis (n = 9). Group IV had patients with reflux esophagitis but no hiatal hernia (n = 16). Esophageal manometry, ambulatory 24 hour intraesophageal pH monitoring, acid clearance test, and gastric emptying scan were performed in each of the patients. The contraction amplitude at 3 cm above the lower esophageal sphincter did not differ significantly among the four groups, but the mean lower esophageal sphincter pressure was significantly decreased in group II. The DeMeester score in ambulatory 24 hour intraesophageal pH monitoring was significantly higher in group III compared with the controls. No significant difference among the groups was found with respect to acid clearance. Total and proximal gastric emptying times (T1/2) were significantly delayed in group III. We found that hiatal hernia combined with delayed gastric emptying may bear a relationship to the multifactorial origins of reflux esophagitis, and we suggest a rationale for using prokinetic agents as the therapeutic regimen in patients with HH complicated by RE.

FACS-based isolation of slowly growing cells: double encapsulation of yeast in gel microdrops

Isolating hyperproducing cells is important in biotechnology, but these cells usually grow slowly and can be overgrown by poorly producing cells. We describe a new method of isolating slowly growing cells from among rapidly growing cells, which has the potential for automation and high throughput (e.g., 100,000 cells/h). A model system is presented consisting of a mixed population of slowly growing mutant and rapidly growing wild-type yeast, which were encapsulated in double agarose gel microdrops (dGMDs); with most dGMDs initially containing single cells. Double encapsulation locates parent cells near dGMD centers, making microcolony measurement more accurate. After a 15-h incubation, fluorescent activated cell sorting was used to analyze and sort dGMDs with small microcolonies (slow growers) from dGMDs with large microcolonies (rapid growers). Successful isolation of slow growers from a mixed population of predominantly rapidly growing Saccharomyces cerevisiae cells was achieved.

Effect of ginsenoside Rb1 on rat liver phosphoproteins induced by carbon tetrachloride

We investigated the effects of ginsenoside Rb1 (G-Rb1), a major saponin from Panax ginseng C. A. MEYER, on rat liver protein phosphorylation after intraperitoneal administration of CCl4 alone or together with G-Rb1. We found that 118, 63, and 34kDa proteins were prominently phosphorylated in liver homogenates prepared from CCl4-administered rats, while these protein-phosphorylations were inhibited in the homogenate prepared from the G-Rb1 plus CCl4-administration group. When inhibitors of protein kinases were exogenously added to the homogenates from either the CCl4-administered group or the G-Rb1 plus CCl4-administered group, their phosphorylations were inhibited much more by W-7, an inhibitor of Ca2+/calmodulin-dependent protein kinase (CaM-PK), than by H-7, an inhibitor of protein kinase C (C-kinase). Interestingly, only 34kDa was phosphorylated in homogenates prepared from the corn oil-, G-Rb1-, and G-Rb1 plus CCl4-administered groups by the exogenous addition of sodium fluoride (NaF), an inhibitor of glycogen synthase. Additionally, G-Rb1 inhibited the Ca(2+)-accumulation induced by CCl4 both in liver homogenates and microsomes. The above results imply that G-Rb1 inhibits the CCl4-induced protein phosphorylations by modulating CaM-PK rather than C-kinase, and that 34kDa protein may play a different biological role in cellular environment from 118 and 63kDa proteins. Therefore, a study in which G-Rb1 is employed as a modulator of critical CCl4-induced phenomena ranging from the disturbance of Ca2+ concentration to protein phosphorylation may be successfully applicable to investigate the diverse physiological functions of liver.

Anorectal dysfunction in systemic sclerosis

This study was aimed to evaluate the anorectal dysfunction in systemic sclerosis (SSc) and propose the clinical significance of anorectal manometry in patients with SSc. Seven patients with SSc were evaluated with manometry for anorectal function and an additional 11 normal subjects were collected as a control group. The study group underwent esophageal manometry as well and the correlation between the degree of anorectal and esophageal dysfunction was evaluated. Patients showed a lower tolerance for balloon distention of the rectum than controls (minimal sensory volume and urgency volume, P < 0.05). The resting and squeezing pressure of the anal sphincter and the functional length of the anal canal showed no significant difference in these two groups. Rectoanal inhibitory reflex was absent in one (14%) and diminished in two (29%) of seven patients with SSc. SSc patients also showed abnormal esophageal manometry findings, notably decreased LES pressure and body amplitude of distal 2/3 esophagus. The comparison between manometric profiles of anorectum and esophagus showed no significant correlation by statistical analysis. In conclusion, our data could suggest that anorectal function may be impaired in patients with SSc which could reflect the involvement of the anorectum by the disease, and that anorectal manometric studies can be useful to detect such dysfunction in patients with SSc, even before clinical symptoms.

Combined treatment of IL-1 alpha and TNF-alpha potentiates the antitumour effect of hyperthermia

Vasoactive cytokines, such as IL-1 alpha and TNF-alpha, modulate the homeostatic state at the endothelial surface and cause various types of pathological damage in vascular systems. We investigated the potential therapeutic effects of IL-1 alpha and TNF-alpha in combination with hyperthermia on SCK tumours grown in the legs of A/J mice. We first determined the effect of cytokines on tumour blood perfusion with the (86)Rb uptake method. When the host mice were given an i.p. injection of 25 mu g/kg IL-1 alpha or 50 mu g/kg TNF-alpha, the tumour blood perfusion markedly declined to 46 and 82% of control, respectively. The combination of IL-1 alpha and TNF-alpha reduced the 86Rb uptake to 41% bf control. Hyperthermia at 42.5 degrees C for 1 h reduced the tumour blood flow to 71% of control. The tumour blood perfusion decreased further to 20% of control when the tumours were heated for 1 h at 42.5 degrees C starting 4h after the injection of both IL-1 alpha and TNF-alpha. The changes in clonogenic cell numbers in SCK tumours, as determined by the in vivo-in vitro assay, following various treatments was also investigated. At 4 h after an i.p. injection of 25 mu g/kg IL-1 alpha or 50 mu g/kg TNF-alpha, the clonogenicity of SCK tumours significantly decreased to 29 or 37% of control, respectively. Heating at 42.5 degrees C for 1 h caused a decline in the clonogenic cell number to 30% of control. When both IL-1 alpha and TNF-alpha were given and tumours were heated 4h later at 42.5 degrees C for 1 h, the clonogenic cell number markedly declined to 0.4% of control. The time needed for control tumours to reach 4 x their initial volume was about 3 days, and treatment with IL-1 alpha or hyperthermia alone induced a tumour delay growth by about 1 day. The combined injection of IL-1 alpha and TNF-alpha followed by a heating at 42.5 degrees C for 1 h delayed the tumour growth by 6 days. The results in this study suggest that prior impairment of blood circulation by the combined treatment of IL-1 alpha and TNF-alpha potentiates hyperthermic damage in tumours.

Spontaneous bowel perforation during the course of acute pancreatitis--a case report

We recently experienced a case of spontaneous perforation of infected necrosis into the colon and duodenum during the course of acute pancreatitis in a 63 year-old male patient. Enteric perforations or fistulas in the setting of acute pancreatitis implicate severe underlying pathology and have substantial morbidity and mortality. In the meantime it has generally been accepted that infected pancreatic or peripancreatic necrosis should be managed surgically as soon as possible. Enteric perforations in the present case contributed to transient improvement of the patient's infection sign and condition, and thus an early operation was able to be avoided. Delayed surgical management resulted in complete recovery of the patient without postoperative morbidity. Herein we report an unusual complication of acute pancreatitis.

Anti-IL-4 antibody inhibits antigen specific IgE response but fails to prevent chicken gamma globulin-induced active systemic anaphylaxis: evidence for the involvement of IgG antibodies

It has recently been reported that interleukin-4 (IL-4) is required for the production of IgE, and anti-IL-4 monoclonal antibody (mAb) inhibits in vivo IgE responses. These suggest that blocking of IL-4 activity may be useful for the prevention or treatment of immediate hypersensitivity disorders. In this study we investigated whether anti-IL-4 has a regulatory role in chicken-gamma globulin (CGG)-induced active systemic anaphylaxis. Multiple injections of anti-IL-4 (up to 40 mg/mouse) failed to protect the mice from fatal anaphylaxis. Anti-IL-4 strongly suppressed CGG-specific IgE response (> 90%) without any suppressive effect on CGG-specific IgG (IgG1, IgG2a, IgG2b, and IgG3) responses. Because these data suggest the possibility that fatal anaphylaxis could be induced by IgG antibodies, we examined the possibility using anti-CGG polyclonal and the subclasses of IgG monoclonal antibodies. Passive sensitization of mice with polyclonal antibodies elicited severe and fatal anaphylactic shock; about 50% of the mice died. The activity of antibodies was not diminished by heat treatment (56 degrees C, 2h), suggesting that the anaphylaxis was not mediated by IgE. Shock was also elicited by each subclass of IgG mAb; of these, IgG1 was the most effective. Combination of the IgG subclasses elicited more exaggerated shock; about 30% of mice died. These data indicate that IgG antibodies are themselves sufficient to induce systemic anaphylaxis. Therefore, the failure of anti-IL-4 to prevent active anaphylaxis is probably due to the inability of anti-IL-4 to suppress the production of IgG antibodies.

A case of paraesophageal hernia repaired by laparoscopic approach

Paraesophageal hernia comprises only 2 approximately 5% of all hiatal hernias but is prone to incarceration and strangulation. For this reason they must be recognized and repaired as expeditiously as possible. The laparoscopic approach has already been successfully applied to the repair of the more common sliding hiatal hernia and it seems reasonable to propose that the paraesophageal hernia, provided it is not complicated, might also be repaired by the laparoscopic technique. We present here a case of paraesophageal hernia which has been successfully repaired by the laparoscopic approach. A 73-year-old female suffering from postprandial fullness in the retrosternal area was diagnosed preoperatively with paraesophageal hiatal hernia with gastroesophageal acid reflux and was submitted for laparoscopic repair. The procedure entailed reduction of the hernia, mobilization of the esophagogastric junction with crural repair and partial fundoplication. At the 9th-month follow-up, the patient had remained asymptomatic and follow-up studies revealed no evidence of hernia or acid reflux. As a result of this favorable experience with minimal morbidity, early hospital discharge, and effective control of symptoms without adverse sequalae, laparoscopic repair can be considered as the curative and minimal invasive method in the management of paraesophageal hernia.

Effect of intracellular acidity and ionomycin on apoptosis in HL-60 cells

The aim was to investigate in detail the influence of intracellular pH (pHi) and intracellular Ca2+ concentration ([Ca2+]i) on apoptosis in HL-60 human promyelocytic leukaemia cells. The pHi was controlled by changing the pH of media as well as by interfering with the pHi regulatory mechanisms with 3-amino-6-chloro-5-(1-homopiperidyl)-N-(diaminomethylene) pyrazincarboxamide (HMA; an inhibitor of Na+/H+ antiport), 4-diiosothiocyanatostilbene-2,2'disulfonic acid, (DIDS; an inhibitor of Na(+)-dependent HCO3-/Cl- exchange) and nigericin (a K+ ionophore). The [Ca2+]i was increased with ionomycin, a Ca2+ ionophore. The apoptosis of HL-60 cells was measured with conventional agarose gel electrophoresis for DNA fragmentation and also with the release of 3H from 3H-thymidine-labelled DNA. Based on the magnitude of DNA fragmentation and 3H release at different pHi, it was shown that apoptosis occurred in HL-60 cells when the pHi was lowered from normal pHi of 7.4 to about 7.2-6.7 with a peak increase at pHi 6.8-6.9. Addition of 4 microM ionomycin to RPMI 1640 medium, which contained 615 microM Ca2+, elevated the apoptosis in the cells. Such an increase in apoptosis by ionomycin in HL-60 cells appeared to result from both an increase in [Ca2+]i and from a decline in pHi. The results indicate that the acidic intratumour environment may greatly affect the response of neoplastic tissues to hyperthermia, radiation and chemotherapeutic drugs which cause apoptosis.

The effect of total saponins from Panax Ginseng C.A. Meyer on the intracellular signalling system in Ehrlich ascites tumor cells

The mechanisms of action of total saponins from Panax Ginseng C.A. Meyer on the elements of intracellular signalling system in Ehrlich ascites tumor cells were studied. The action of total saponins was compared with the effect of ATP, a classical activator of these cells. Saponins at concentrations of 10(-6)-10(-3)% increased [Ca2+]i, mobilized Ca2+ ions from the endoplasmic reticulum (ER) and activated the influx of Ca2+ to cells. Like ATP, saponins activated the Na+/H+ exchange and Ca(2+)-dependent K+ channels. Of all the parameters, only the activation of Ca2+ influx in cell is directly affected by saponins. The changes in other parameters are connected with nonspecific activation of purinoreceptors. The analysis of the kinetic data suggests that, as distinct from ATP-dependent activation of purinoreceptor, saponins first activate the Ca2+ influx to cells and only then induce the mobilization of Ca2+ from ER.

Amber suppression in mammalian cells dependent upon expression of an Escherichia coli aminoacyl-tRNA synthetase gene

As an approach to inducible suppression of nonsense mutations in mammalian and in higher eukaryotic cells, we have analyzed the expression of an Escherichia coli glutamine-inserting amber suppressor tRNA gene in COS-1 and CV-1 monkey kidney cells. The tRNA gene used has the suppressor tRNA coding sequence flanked by sequences derived from a human initiator methionine tRNA gene and has two changes in the coding sequence. This tRNA gene is transcribed, and the transcript is processed to yield the mature tRNA in COS-1 and CV-1 cells. We show that the tRNA is not aminoacylated in COS-1 cells by any of the endogenous aminoacyl-tRNA synthetases and is therefore not functional as a suppressor. Concomitant expression of the E. coli glutaminyl-tRNA synthetase gene results in aminoacylation of the suppressor tRNA and its functioning as a suppressor. These results open up the possibility of attempts at regulated suppression of nonsense codons in mammalian cells by regulating expression of the E. coli glutaminyl-tRNA synthetase gene in an inducible, cell-type specific, or developmentally regulated manner.

Light signal transduction mediated by phytochromes: preliminary studies and possible approaches

Phytochromes mediate a variety of developmental and growth processes involved in the photomorphogenesis of plants. In this article, we review the current understanding of the structure and function of the photoreceptor, discuss some very preliminary results, and offer speculations and even conjectures that may elicit future studies into the molecular mechanisms of the phytochrome-mediated light signal transduction in plants.

The role of insulin in the interaction of secretin and cholecystokinin in exocrine secretion of the isolated perfused rat pancreas

To investigate the role of insulin in the potentiation effect of secretin and cholecystokinin (CCK) on pancreatic exocrine secretion, the pancreas was isolated from rats and perfused with modified Krebs-Henseleit solution containing glucose at three concentrations. Intraarterial glucose at concentrations of 2.5, 10, and 25 mM produced modest but significant increases in both the pancreatic flow rate and the amylase output in a concentration-dependent manner. The mixture of secretin and CCK at concentrations of 18.5 and 14 pM, respectively, added to the glucose solutions augmented the pancreatic flow rate and amylase output in relation to the glucose concentration. In the streptozotocin-treated pancreas, the mixture of secretin and CCK failed to augment the pancreatic exocrine secretion unless exogenous insulin was added to the perfusate. Secretin markedly potentiated the CCK-induced amylase output when insulin was present in the circulation. However, CCK did not potentiate the secretin-induced flow rate even if insulin was present in the circulation. Insulin did not affect the actions of secretin alone but it potentiated the actions of CCK alone in both the pancreatic flow rate and the amylase output. It is concluded from the above results that insulin intensifies the combined actions of secretin and CCK in pancreatic exocrine secretion by potentiating the CCK action. Furthermore, in the presence of insulin, secretin is able to potentiate the pancreatic enzyme secretion stimulated by CCK.

Temporal corneal phacoemulsification combined with superior trabeculectomy: a controlled study

OBJECTIVE

To determine the intraocular pressure (IOP)-lowering effects of combined temporal corneal phacoemulsification and separate incision superior trabeculectomy with those of trabeculectomy alone.

METHODS

This is a retrospective case-control study of 40 consecutive patients who underwent combined temporal corneal phacoemulsification and superior trabeculectomy with low-dose 5-fluorouracil (5-FU) (cases), and 40 eyes matched with respect to age, race, preoperative medications, and preoperative IOP that had trabeculectomy alone with low dose 5-FU (controls). Survival analyses for IOP were performed for the cases and controls. We reviewed the charts of 40 consecutive patients who underwent combined temporal corneal phacoemulsification and superior trabeculectomy with low dose 5-FU to determine the effect on IOP, visual acuity, and requirement for glaucoma medications. For controls, we chose 40 eyes matched with respect to age, race, preoperative medications, and preoperative IOP who had trabeculectomy alone with low dose 5-FU. In both groups, trabeculectomy was performed with the same technique, was located superiorly, and employed a limbus-based conjunctival flap. In the combined surgery group, temporal corneal phacoemulsification immediately preceded trabeculectomy and employed a 3.5-mm incision and a one-piece silicone intraocular lens. All patients received 3 or 4 subconjunctival 5-FU injections of 5 mg each over the first 11 postoperative days. Patients were followed up for at least 1 year. Success of trabeculectomy was defined as an IOP less than 22 mmHg and 20% or more reduction from the preoperative level on 2 consecutive follow-up visits, regardless of the use of antiglaucoma medications.

RESULTS

The mean postoperative intraocular pressure was higher in the combined surgery group than in the control group at each follow-up interval (P < 0.05). The mean (+/- SD) IOP reduction was 6.8 (+/- 5.5) mmHg in the combined surgery group, and 10.3 (+/- 7.6) mmHg in the trabeculectomy group at 1 year. The reduction in the number of antiglaucoma medications was 1.6 (+/- 0.9) in the combined surgery group and 2.0 (+/- 1.0) in the control group at 1 year. In the combined surgery group, the mean visual acuity beyond the first postoperative month was significantly better than at baseline (P < 0.001). Kaplan-Meier survival analysis showed that the cumulative success rate at 2 years was 62% in the combined surgery group and 86% in the trabeculectomy group. The time to failure was significantly shorter (P = 0.04) in the combined surgery group.

CONCLUSIONS

Combined surgery for cataract and glaucoma is associated with less long-term IOP reduction compared with trabeculectomy alone, despite identical trabeculectomy techniques in both groups. Nevertheless, combined surgery effectively lowers IOP and reduces the long-term requirement for antiglaucoma medications without additional complications. This technique is appropriate in selected patients with coexisting cataract and glaucoma.

Chemistry and antimicrobial activity of caryoynencins analogs

Caryoynencins (1) are antibiotics isolated from liquid cultures of a plant pathogen, Pseudomonas caryophylli, and are unstable C18 carboxylic acids with a conjugated dienetetrayne structure. Enyne analogs of caryoynencins were synthesized from monosilylated 1,3-butadiyne 2 (n = 2), 1,3,5-hexatriyne 2 (n = 3), and 1,3,5,7-octatetrayne 2 (n = 4) by alkynyl metal addition to 2,4-hexadienal (3) followed by allylic rearrangement and deprotection. Tetraynol 5 (n = 4) thus obtained was resolved by enzyme reactions. The conjugated dienetetrayne compounds are mixtures of 3E,5E- and 3E,5Z-isomers, which equilibrate by room light. 13C-NMR chemical shifts of polyynes obey simple rules, which can be used for signal assignments. Antimicrobial activities of conjugated enynes and related compounds were examined. The tetrayne analog 6 (n = 4) possesses potent antibacterial and antifungal activities, while triyne and diyne analogs 6 (n = 3 and 2) are less active. Chirality does not affect the activities. An isomeric enyne compound, 2,4-tetradecadiene-7,9,11,13-tetrayn-6-ol (8), showed potent activity against Tricophyton.

Interleukin-1 beta facilitates afferent sensory transmission in the primary somatosensory cortex of anesthetized rats

The effect of topical application of human recombinant interleukin-1 beta (IL-1) on afferent sensory transmission to the neurones in the primary somatosensory (SI) cortex was determined in anesthetized rats. Quantitative determination of the effect of IL-1 was made by generating post-stimulus time histograms of unit responses to the stimulation of receptive field. IL-1 (0.01, 0.1, 1.0 U) significantly facilitated afferent sensory transmission in SI cortical neurones (n = 22). IL-1-induced facilitation fully recovered by 60 min after drug. In control experiments (n = 10), saline solution containing 0.2 bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Our results suggest that IL-1 may be involved in the processing of afferent sensory information in the SI cortex of rats.

Effect of non-saponin fraction from Panax ginseng on cGMP and thromboxane A2 in human platelet aggregation

The non-saponin fraction (NSF; lipophilic fraction) from the roots of Panax ginseng inhibited the aggregation of human platelets induced by thrombin (0.1 units/ml) in a dose-dependent manner. NSF induced the elevation of cGMP concentration in human platelets in a similar manner to molsidomine, a known vasodilator. NSF also inhibited Ca(2+)-influx into platelets. While verapamil, a Ca(2+)-antagonist, increased the cAMP level in platelets stimulated by thrombin, NSF had little effect on cAMP formation. Instead, NSF potently inhibited the thromboxane A2 (TXA2) production. The results suggest that NSF may regulate the levels of cGMP and TXA2 to inhibit platelet aggregation induced by thrombin.

Effects of intracellular pH on apoptosis in HL-60 human leukemia cells

The nature of the endonucleases responsible for DNA fragmentation in apoptosis has not yet been clearly defined. The intracellular acidity has been known to greatly affect apoptosis probably by affecting the activity of the endonucleases. In this study, the implication of pH in the apoptosis was investigated through the use of human HL-60 leukemia cells. The cells were incubated in media with different pH ranging from 3.5 to 7.5 for 4 hrs and the mode of cell death was investigated. The trypan blue exclusion assay showed that close to 25% and 90% of the cells were dead when incubated in pH 6.4 and pH 5.0 media, respectively. The agarose gel electrophoresis of DNA demonstrated that significant DNA fragmentation occurred in the HL-60 cells incubated in the pH 6.2-6.4 media for 4 hr indicating cell death by apoptosis. The electron microscopy study also demonstrated that many of the cells incubated in the pH 6.4 medium were in the process of apoptosis while the cells maintained in the pH 5.0 medium were dying by necrosis. The intracellular pH (pHi) of HL-60 cells was 6.6-6.9 when the extracellular pH (pHe) was 6.2-6.4. These results demonstrated that DNase I which has a maximal endonuclease activity near pH 7.0 may be responsible for the apoptosis accompanied by DNA fragmentation in HL-60 cells in the pH 6.4 medium. This observation is at variance with the previous reports that DNase II mediate the DNA fragmentation in apoptosis. The cell death at extremely low pH (pH 5.0) appeared to be due mainly to necrosis.

Proctographic features of anismus

PURPOSE

To document the proctographic features of anismus at evacuation proctography and determine the optimum radiologic measurements for diagnosis.

MATERIALS AND METHODS

Twenty-four patients with anismus according to clinical and multiple physiologic criteria were examined with evacuation proctography. Structural and functional measurements were compared with those of a group of 20 asymptomatic subjects.

RESULTS

No significant difference between patients and control subjects was found with respect to pelvic descent, rectocele, or any anorectal angle measurement. In patients with anismus, initiation of evacuation was prolonged (median, 9 vs 3 seconds for control subjects; P < .0001) and anal canal width was reduced (median, 0.6 vs 1.2 cm; P = .0075). Evacuation time was increased (median, 50 vs 10 seconds; P < .0001), and the percentage of contrast material evacuated was decreased (median, 60% vs 100%; P < .0001). Only four patients were able to evacuate more than 66% of the contrast material within 30 seconds, whereas all control subjects were able to do so.

CONCLUSION

Measurement of the anorectal angle to diagnose anismus should be abandoned. Patients with anismus demonstrate delayed initiation of evacuation, which is also prolonged and incomplete. Incomplete evacuation after 30 seconds is highly suggestive of anismus.

Crystal structure of NADH oxidase from Thermus thermophilus

The crystal structures of the flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) containing isoforms of NADH oxidase from Thermus thermophilus have been determined by isomorphous and molecular replacement and refined to 2.3 A and 1.6 A resolution with R-values of 18.5% and 18.6% respectively. The structure of the homodimeric enzyme consists of a central 4-stranded antiparallel beta-sheet covered by helices, a more flexible domain formed by two helices, and a C-terminal excursion connecting the subunits. The active sites are located in a deep cleft between the subunits. The binding site of the flavin cofactor lacks the common nucleotide binding fold and is different from the FMN binding site found in flavodoxins.

A trace component of ginseng that inhibits Ca2+ channels through a pertussis toxin-sensitive G protein

A crude extract from ginseng root inhibits high-threshold, voltage-dependent Ca2+ channels through an unknown receptor linked to a pertussis toxin-sensitive G protein. We now have found the particular compound that seems responsible for the effect: it is a saponin, called ginsenoside Rf (Rf), that is present in only trace amounts within ginseng. At saturating concentrations, Rf rapidly and reversibly inhibits N-type, and other high-threshold, Ca2+ channels in rat sensory neurons to the same degree as a maximal dose of opioids. The effect is dose-dependent (half-maximal inhibition: 40 microM) and it is virtually eliminated by pretreatment of the neurons with pertussis toxin, an inhibitor of G(o) and Gi GTP-binding proteins. Other ginseng saponins--ginsenosides Rb1, Rc, Re, and Rg1--caused relatively little inhibition of Ca2+ channels, and lipophilic components of ginseng root had no effect. Antagonists of a variety of neurotransmitter receptors that inhibit Ca2+ channels fail to alter the effect of Rf, raising the possibility that Rf acts through another G protein-linked receptor. Rf also inhibits Ca2+ channels in the hybrid F-11 cell line, which might, therefore, be useful for molecular characterization of the putative receptor for Rf. Because it is not a peptide and it shares important cellular and molecular targets with opioids, Rf might be useful in itself or as a template for designing additional modulators of neuronal Ca2+ channels.

Dysphagia due to mediastinal tuberculous lymphadenitis presenting as an esophageal submucosal tumor: a case report

Mediastinal tuberculous lymphadenitis is rare in adults, and it is even rarer for dysphagia to be the presenting symptom of mediastinal tuberculous lymphadenitis. Mediastinal tuberculous lymphadenitis with esophageal symptoms has been presented as esophageal ulceration, mucosal or submucosal mass with ulceration, fistula or sinus formation, extrinsic compression, or displacement of the esophagus. An exaggerated form of extrinsic compression may be presented as a submucosal tumor, radiologically or endoscopically. A barium esophagography of a 34 year-old woman with painful dysphagia revealed a large submucosal tumor-like mass on the mid-esophagus. The symptom was spontaneously improved over a 3-week period together with reduction of the mass size. A computed tomography of the chest disclosed an enlarged subcarinal lymph node and histologic examination of the specimen obtained by thoracoscopic biopsy brought about a diagnosis of tuberculosis. We herein report a case of mediastinal tuberculosis with unusual manifestations.

Long-term follow-up of gracilis muscle transposition in children

Sixteen children of uncontrollable fecal incontinence have been treated with Pickrell's gracilis muscle transposition since 1983: 12 had an imperforate anuses with multiple corrective operative procedures and 4 had traumatic destructions of anal sphincters. We report a series of 11 cases whom we followed-up over a period of 0.8 to 10.5 years (mean; 5.6 years). Seven patients were evaluated by anorectal manometry. All patients except one who had left hemipelvectomy and permanent colostomy showed nearly normal continence during the follow-up period. There was no evidence of fibrosis in the transposed muscles and the tensions of the transposed muscles were well maintained. The voluntary contractions of the transposed muscles were well maintained and efficient in all cases. The general manometric parameters did not correlate well with the functional results; however, there was a strong correlation in the S/R ratio (maximum squeeze pressure/resting pressure) with the functional results. We believe that the good functional outcome of this procedure need not only the meticulous surgical technique but also the personal motivation and the compliance with physiotherapy. In conclusion, although the gracilis muscle transposition never results in normal continence, acceptable continence can be achieved in the selected patients.

A case of abdominal cocoon

Abdominal cocoon is a rare disease of the peritoneum and almost invariably presents as an acute or subacute intestinal obstruction with or without a mass. The etiology of this disease is largely unknown and abdominal cocoon of unknown etiology has been limited to the tropical and subtropical zones and primarily affects young adolescent females. In the temperate zone, only one case has been reported from the United Kingdom, but the patient was also born in Pakistan. No case of abdominal cocoon purely developed in the temperate zone has been reported. Recently, we experienced a case of abdominal cocoon in a 34-year-old female patient(Korean) who had never been abroad. The diagnosis was made postoperatively by reviewing the literature. We herein report this rare condition developed in an unusual geographical location with a brief review of the literature.

Interleukin 2 suppresses afferent sensory transmission in the primary somatosensory cortex

The effect of topical application of interleukin 2 (IL-2) on afferent sensory transmission to the neurones in the primary somatosensory (SI) cortex was determined quantitatively in anaesthetized rats. IL-2 (0.1, 1.0, 5.0 units) significantly suppressed afferent sensory transmission in SI cortical neurones (n = 19) in a dose-dependent manner. IL-2-induced suppression fully recovered by 60 min after drug. In control experiments, saline solution containing 0.2% bovine serum albumin, used as a vehicle, did not affect afferent sensory transmission. Our results suggest that IL-2 and its receptor present in the SI cortex may be involved in the processing of afferent sensory information.

Immunohistochemical study of the colonic muscle and innervation in idiopathic chronic constipation

PURPOSE

This study was designed to investigate neural and muscular features of the colonic wall in patients with severe idiopathic constipation.

METHODS

By using quantitative immunohistochemistry, resected specimens from 14 patients with idiopathic chronic constipation and 17 nonobstructed cancer controls were studied.

RESULTS

Routine histology revealed no significant histologic abnormality throughout the colon apart from four cases of melanosis coli. Ratio of the thickness of circular to longitudinal muscle was significantly lower in the left colon in constipated subjects. The myenteric plexus appeared morphologically normal in all subjects. S-100 protein, which stains neuronal supporting tissues, demonstrated an increase in the proportion of neural tissue in the myenteric plexus. There was an increased number of PGP-9.5 immunoreactive nerve fibers in the muscularis propria in constipated patients, and this was significantly higher in the ascending and descending colon.

CONCLUSION

Intractably constipated patients have alterations in the neural composition of the colonic myenteric plexus and innervation of the circular muscle.

Central projection of the peripheral cochlear nerve from each turn to the cochlear nuclei in the Mongolian gerbil

The central projections of the peripheral cochlear nerve fiber from each turn to the cochlear nuclei (CN) in the mongolian gerbil were investigated using retrograde transportation of horseradish peroxidase (HRP). The organ of Corti and the osseous spiral lamina were scratched with an electrolytically-sharpened fine needle via a small hole at each turn of the cochlea. The cochlea was filled with a 30% horseradish peroxidase (HRP) solution. After 48 hours, 50 microns transverse serial sections of the brainstem were made with a vibratome. The tissue was processed with the diaminobenzidine procedure of the cobalt-glucose method. Our experiment revealed that the fibers from the basal turn terminated at the dorsomedial portion of anteroventral cochlear nuclei (AVCN), but those from the apical turn were distributed among the ventrolateral portion of the AVCN. In the posteroventral cochlear nuclei (PVCN) and dorsal cochlear nuclei (DCN), the fibers from basal to apical turns extend from the dorsal to the ventral portion of each nuclei. A distinct tonotopic arrangement could be found between the origin of cochlear fibers of each turn and their termination in the regions of the cochlear nuclei (CN). Also, the results suggested that the scratch method combined with retrograde transportation of horseradish peroxidase was useful in investigating the tonotopic arrangement of the peripheral auditory nerve in the CN.

Pancreatic exocrine secretion in response to median raphe stimulation in anesthetized rats

To investigate a possible role of the central serotonergic system in the central control of pancreatic exocrine secretion, the median raphe nucleus of the anesthetized rat was electrically stimulated. The parameters of the biphasic square wave stimulus were 2 V, 2 ms, and 40 Hz. Electrical stimulation of the median raphe nucleus for 10 min resulted in large increases in pancreatic volume flow and protein output. The pancreatic responses were completely abolished by spinal cord transection at the level between C4 and C5. Cervical vagotomy or adrenalectomy failed to attenuate the pancreatic responses. The median raphe stimulation evoked a remarkable elevation of the blood pressure of the carotid artery as well as the plasma concentrations of noradrenaline and adrenaline. The responses were also completely inhibited by spinal cord transection but unaffected by cervical vagotomy. Adrenalectomy blocked the elevation of the plasma concentration of adrenaline only. Noradrenaline, given intravenously, stimulated the pancreatic volume flow and protein output. The actions of noradrenaline were antagonized by propranolol but not by phentolamine. It is, therefore, concluded from the present study that the median raphe nucleus may play a stimulatory role in pancreatic exocrine secretion of anesthetized rats and that the stimulatory role is mediated via the sympathetic nervous system acting on beta-adrenoceptors.

A large common bile duct stone migrated from the gallbladder through a cholecystohepaticodochal fistula: an unusual complication of Mirizzi syndrome type II

Mirizzi syndrome with a biliobiliary fistula (Mirizzi syndrome type II) is a rare complication of a long-standing gallbladder stone disease. It is even rarer for a gallbladder stone to migrate through a biliobiliary fistula into the common duct. We encountered this interesting complication of Mirizzi syndrome type II in an 86 year-old female patient. A large gallbladder stone migrated into, and impacted into the distal common bile duct through a cholecystohepaticodochal fistula. The stone was resistant to mechanical lithotripsy and was treated with biliary endoprosthesis and oral bile acids.

Identification of immunodominant epitopes in the core and non-structural region of hepatitis C virus by enzyme immunoassay using synthetic peptides

Thirty-two synthetic peptides, components of the core and non-structural protein of Hepatitis C virus (HCV), were tested for their reactivities against antibodies in sera of healthy, HCV antibody positive of chronic liver disease patients. Among them, 8 of the core peptides, 4 of the NS4 peptides and 3 of the NS5 peptides reacted with the HCV infected sera. In particular, C22 (core peptide) and NS4-1924 (NS4 peptide) were most reactive with the serum samples giving a positive signal with commercially available enzyme-linked immunosorbent assay (ELISA) kit. Our results indicate that the immunodominant regions of the HCV-derived proteins are located at three regions in the core protein, three regions in the NS4 protein, and one region in the NS5 protein. These results indicate that the selected peptides are useful antigens in detecting antibodies in the sera from individuals infected with HCV.

Redistribution of facial nerve motor neurons after recovery from nerve crushing injury in the gerbil

We investigated the redistribution of facial motor neurons after recovery from a crush injury of the facial nerve in the mongolian gerbil, with the retrograde transportation of horseradish peroxidase (HRP) technique. The facial nerve at the vertical segment was crushed unilaterally for 10 s with forceps. After 1 month, movement of the vibrissae and blinking reflex were observed. Three months after nerve injury, we obtained the brainstems to investigate the distribution of the facial nerve motor neurons. On the normal side, motor neurons of the ophthalmic branch of the facial nerve were organized at the dorsomedial and dorsolateral subdivisions of the facial nucleus, and those of the superior buccal branch were distributed at intermediate and ventrolateral subdivisions of the facial nucleus in the brainstem. On the experimental side, instead of somatotopical organization, we found widespread irregular distribution of the motor neurons of both branches in the entire facial nucleus of the brainstem.

Bombesin-induced changes of sensory transmission in the dorsal column nuclei

Bombesin was intracisternally administered to determine the effects on the neuronal activities of the dorsal column nuclei (DCN) of anesthetized rats. Although averaged afferent somatosensory transmission through 22 DCN neurons did not appear to be altered by bombesin (-1.11 +/- 3.5%), 12 of them were actually augmented (+17.15 +/- 2.7%) and 10 of them were suppressed (-26.15 +/- 4.9%) during 40 min after bombesin (0.01 microgram) administration. Pretreatment of a bombesin antagonist ([Leu13,Psi(CH2NH)Leu14]bombesin, 0.1 microgram) blocked the effects of bombesin. Lower dose (0.001 microgram) of bombesin did not exert any influences. These results suggest that bombesin may heterogeneously influence afferent somatosensory information in the brain stem of the rat.

Quantitative analysis of changes of automated perimetric thresholds after pupillary dilation and induced myopia in normal subjects

We quantitatively analyzed the changes of the (retinal) threshold sensitivities between normal status and dilated emmetropic status, and between dilated emmetropic status and -1.0D induced myopic status. Three consecutive visual field examinations by Humphrey Field Analyzer C-30-2 threshold test and STATPAC program were performed in 36 eyes of 21 normal subjects who ranged in age from 23 to 40 years. The results were as follows: 1) There was a statistically significant decrease (0.87 +/- 0.91dB)in the mean threshold sensitivity within the central 30 degrees at the dilated emmetropic status (27.90dB) as compared with the normal status (28.77dB)(p = 0.0001). 2) There was a statistically significant decrease(0.99 +/- 0.61dB) at -1.0D induced myopic status(26.91dB) as compared with the dilated emmetropic status(27.90dB)(p = 0.0001). 3) After dilation, the mean threshold sensitivity between 20 and 30 degrees of field showed statistically significant decrease as compared with those within the central 20 degrees of visual field(p < 0.05). In case of -1.0D induced myopia, there were uniform decreases in the mean threshold sensitivities within the central 30 degrees of visual field (p > 0.05). Therefore, we emphasize the importance of consistent pupillary size and correct refractive state in performing the serial automated visual field tests.

Potentiation by capsaicin of lidocaine's phasic impulse block in isolated rat sciatic nerve

Compound action potentials (CAPs) of A- and C-fibres were recorded from isolated sciatic nerves of the rat to determine whether lidocaine-induced phasic impulse block was affected by low doses of capsaicin. Preceding impulse activity produced phasic reductions of the amplitudes of both A- (5.7 +/- 1.3%) and C-CAPs (20.7 +/- 7.0%) in drug-free solution. Capsaicin alone (50 microM) did not change the activity-induced reductions of the heights of both CAPs (A-CAP: 6.2 +/- 1.7%, C-CAP: 22.3 +/- 8.0%). Lidocaine (100 microM) caused differential phasic blocks between the A-CAP (20.1 +/- 3.7%; n = 7) and the C-CAP (33.8 +/- 4.9% n = 7). Lidocaine's phasic impulse block was potentiated after 30 min of subsequent capsaicin administration (A-CAP: 40.6 +/- 4.7%, n = 7; C-CAP: 48.8 +/- 5.5% n = 9). Capsaicin's phasic potentiating effects were reversed after 30 min of washing. These results suggest that capsaicin may be a useful agent for the reversible potentiation of phasic impulse blockade by lidocaine.

Potentiation by capsaicin of lidocaine's tonic impulse block in isolated rat sciatic nerve

Compound action potentials (CAPs) of A- and C-fibers were recorded from isolated sciatic nerves of the rat to determine whether tonic block of impulse conduction induced by lidocaine was affected by low doses of capsaicin. Capsaicin alone (50 microM) did not change the CAPs of either A- or C-fibers. Although the lower concentrations of capsaicin (5-30 microM) caused no change of the tonic blocking action of lidocaine, 30 min of 50 microM capsaicin administration did induce a significant potentiation of tonic block. Capsaicin's potentiating effects were partially reversed after 30 min of wash. These results suggest that capsaicin may be a useful agent for the potentiation of impulse blockade by lidocaine.

Solitary rectal ulcer syndrome

We report three cases of solitary rectal ulcer syndrome (SRUS). The diagnosis was established according to histopathologic criteria. But, the initial clinical diagnosis was carcinoma, non-specific ulcer and localized proctitis respectively. SRUS is considered as one of functional disorder in pelvic floor which might go underdiagnosed due to unfamiliar concept in Korea. So we should consider SRUS to be one of the differential diagnosis in cases of complaining anorectal symptoms.

Activity-dependent variations in conduction velocity of C fibers of rat sciatic nerve

Changes in the conduction velocity and subsequent conduction block were characterized following impulse activity in single C fibers of rat sciatic nerves. C fibers which had the same resting conduction velocities often exhibited quite different profiles of the activity-dependent latency change and/or conduction block following impulses. The results imply underlying variation among C fibers in the activity-dependent excitability changes, especially in the build-up and recovery of the hypoexcitable phases.

Differential phasic modulation of short and long latency afferent sensory transmission to single neurons in the primary somatosensory cortex in behaving rats

Single neurons were recorded in the forepaw area of the primary somatosensory (SI) cortex of awake rats during rest and running behavior. Locomotor step cycle dependent changes of the transmission of the short (4.5 +/- 0.1-10.5 +/- 0.1 ms, SEURs) and the long (10.6 +/- 0.6-28.5 +/- 2.3 ms, LEURs) latency evoked unit responses were tested by generating post-stimulus time histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw. Times of footfall were determined by way of frame-by-frame analyses of video recordings, and peri-footfall histograms were generated to differentiate a total of 55 SI cortical neurons into two types: footfall responsive (n = 37) and footfall unresponsive (n = 18) neurons. Peri-footfall gating patterns were determined for both types of cells. The SEURs and the LEURs showed significantly different phasic sensory modulation patterns. A major difference in sensory modulations between footfall responsive and footfall unresponsive cells was noted during the swing phase of the locomotor step cycle. In footfall responsive cells, the SEURs were suppressed most strongly just after footfall, while the LEURs were phasically suppressed following both footfall and footoff. The SEURs were disinhibited during the swing phase. In footfall unresponsive cells, the SEURs were tonically suppressed during the whole locomotor step cycle phases. However, the LEURs were phasically facilitated during the early swing phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression cloning of the nox, mdh and ldh genes from Thermus species encoding NADH oxidase, malate dehydrogenase and lactate dehydrogenase

The Thermus thermophilus HB8 mdh and ldh genes and the T. aquaticus EP00276 nox and mdh genes encoding the biotechnologically important enzymes NADH oxidase (EC 1.6.99.3), malate dehydrogenase (EC 1.1.1.37) and lactate dehydrogenase (EC 1.1.1.27) were cloned on the basis of known sequences from related species using the polymerase chain reaction. The nox and mdh genes were directly placed under the control of regulatory expression elements from Escherichia coli. When the 5'-portions of the re-cloned nox gene and the mdh gene of T. thermophilus HB8 were simultaneously altered, enzyme yields of 18-42% of the total soluble cellular protein were obtained as compared to 2-6% obtained from the unchanged genes. The high overproduction level upon the alterations can be explained by the occurrence of additional potential base pairs between nucleotides in the mRNA downstream of the start codon ('downstream box') and the 16S rRNA. An 'universal translation initiation sequence' providing such strong interactions may be of general use for high overproduction levels.

Alkylation of guanine and cytosine in DNA by bizelesin. Evidence for a covalent immobilization leading to a proximity-driven alkylation of normally unreactive bases by a (+)-CC-1065 cross-linking compound

Bizelesin, an intrahelical DNA-DNA interstrand cross-linker related to (+)-CC-1065, has been shown to alkylate DNA through guanine in restriction enzyme sequences in which there is a suitably positioned adenine contained in a highly reactive monoalkylation sequence on the opposite strand. Oligomers containing the sequence 5'-TTTTTN*, in which "N" was either G, C, or T, were synthesized to evaluate the cross-linking potential of bizelesin at nonadenine bases. Kinetic analysis of monoalkylation and cross-linking events demonstrates that it is the reaction at "N" (guanine or cytosine) that results in the cross-link which is the slow step. On the basis of this analysis and the normal unreactivity of guanine and cytosine to alkylation by the cyclopropapyrroloindole alkylating moiety of (+)-CC-1065, we propose that the molecular mechanism for this type of cross-linking reaction most likely involves a covalent immobilization of the second alkylating arm, resulting in a "proximity-driven" reaction.

Differential phasic modulation of short and long latency afferent sensory transmission to single neurons in the ventroposterolateral thalamus in behaving rats

Single neurons were recorded in the forepaw area of the ventroposterolateral (VPL) thalamus of awake rats during rest and running behaviors. Locomotor step cycle dependent changes of the transmission of the short (4.0 +/- 0.1-10.1 +/- 0.3 ms, SEURs) and the long (10.2 +/- 0.2-26.0 +/- 2.1 ms, LEURs) latency somatic sensory responses were tested by generating post-stimulus time histograms of these neurons' responses to stimulation through electrodes chronically implanted under the skin of the forepaw. The magnitudes of firing during these responses were measured and normalized as percent increases over background firing. Times of footfall were determined through frame-by-frame analyses of video recordings and peri-footfall histograms were generated to differentiate a total of 40 VPL thalamic neurons into two types, footfall responsive (n = 21) and unresponsive (n = 19) neurons. Perifootfall gating patterns were determined for both types of cells. The SEURs and the LEURs showed significantly different phasic sensory modulation patterns across the locomotor step cycle. Major difference of the sensory modulations between footfall responsive and footfall unresponsive cells was noted during swing phase of the locomotor step cycle. In footfall responsive cells, the SEURs were suppressed most strongly just after footfall, while the LEURs were tonically suppressed during late stance and swing phases. The SEURs were disinhibited during the swing phase, while the LEURs were disinhibited during the middle stance phase. In footfall unresponsive cells, the LEURs were suppressed more strongly around footfall event than the SEURs were.(ABSTRACT TRUNCATED AT 250 WORDS)