Phentolamine effect on the spontaneous electrical activity of active loci in a myofascial trigger spot of rabbit skeletal muscle

OBJECTIVE

To investigate the effect of phentolamine, a sympathetic blocking agent, on the spontaneous electrical activity (SEA) recorded from a locus of a myofascial trigger spot (MTrS), equivalent to a human trigger point, in rabbit skeletal muscle.

DESIGN

Randomized control trial.

SETTING

A university medical laboratory.

PATIENTS OR OTHER PARTICIPANTS

Nine adult New Zealand rabbits.

INTERVENTION

In the experimental group phentolamine mesylate (1mg/kg) was injected into the external iliac artery, followed by flushing with normal saline. The control group was treated with normal saline instead of phentolamine using the same procedure.

MAIN OUTCOME MEASURES

SEA was recorded from multiple active loci of MTrSs in the biceps femoris muscle: initially SEA in the same locus was recorded before and immediately after phentolamine (or normal saline) injection; then SEA was recorded from 25 different active loci. The mean of the average integrated signal (AIS) of SEA was analyzed, comparing the effects of phentolamine and normal saline on SEA.

RESULTS

In the same active locus, the AIS of SEA showed statistically a linear decay with time after phentolamine injection, with a correlation coefficient of .56 at p < .05. However, no statistical relationship could be derived for the control group data with time by using regression analysis, probably because of large variations among the rabbits and movement artifacts during the experiment. In 25 different loci in the phentolamine group, the mean of the AIS of SEA (7.92 microV) was significantly lower than that of the control group (9.89 microV) at p < .05.

CONCLUSIONS

The results support the hypothesis that the autonomic nervous system is involved in the pathogenesis of myofascial trigger points. The application of the AIS as an evaluation index seems to be feasible in the quantitative measurement of SEA.

Sequencing multimegabase-template DNA with BigDye terminator chemistry

Using the recently introduced BigDye terminators, large-template DNA can be directly sequenced with custom primers on automated instruments. Cycle sequencing conditions are presented to sequence DNA samples isolated from a number of microbial genomes including 750-kb Ureaplasma urealyticum, 1.2-Mb Mycoplasma fermentans, 2.3-Mb Streptococcus pneumoniae, and 4.6-Mb Escherichia coli. Average read lengths of >700 bp from unique primer annealing sites are often sufficient to fill final gaps in microbial genome sequencing projects without additional manipulations of template DNA. The technique can also be applied to sequence-targeted regions, thereby bypassing tedious subcloning steps.

Ultrastructural differentiation of the genogroups in the genus Ehrlichia

Ultrastructural characteristics of 15 strains and isolates of ehrlichiae belonging to three genogroups, or clades of genetically related organisms united in the genera Ehrlichia, Cowdria, Anaplasma, Neorickettsia and a strain of Wolbachia pipientis which represents a fourth genogroup in this cluster of species, were studied in continuous cell culture or in vivo: E. canis (Oklahoma strain and VHE isolate), E. muris (AS 145), E. chaffeensis (Arkansas, 91HE17 and Sapulpa), human granulocytic ehrlichiae (HGE)(BDS, 96HE27, 96HE37, #54, #55 and #72), E. equi (MRK), E. sennetsu (Miyayama), E. risticii (HRC-IL). Wolbachia pipientis was studied in the naturally infected Aedes albopictus mosquito cell line Aa23. All organisms were similar in the normal ultrastructure of individual cells and in the ability to form abnormal, pathological ehrlichial cells of the same type irrespective of the species. Normally all ehrlichiae studied in cell culture existed in two morphological forms - reticulate and dense-cored cells, both of which could divide by binary fission. Most alterations were related to their membranes, especially the cell wall. Differences in the structure of intravacuolar microcolonies (morulae) of ehrlichiae and their inter-relations with the host cells allowed differentiation of the genogroups: the E. canis-E. chaffeensis-E. muris genogroup formed large morulae, with many ehrlichiae, often suspended in a fibrillar matrix, and the host cell mitochondria and endoplasmic reticulum usually aggregated near the morulae and were in contact with the morula membrane; the E. phagocytophila-E. equi-HGE group morulae had no fibrillar matrix, no contacts with host cell mitochodria, and they did not aggregate around the morulae; E. sennetsu-E. risticii group usually developed in small individual vacuoles that did not fuse with each other and divided along with the ehrlichiae.

Haemodynamic effects of chronic octreotide and tetrandrine administration in portal hypertensive rats

Octreotide is an effective portal hypotensive drug in the control of variceal bleeding. Tetrandrine is a type of calcium channel blocker recently reported to reduce portal hypertension. The present study was undertaken to investigate the haemodynamic effects of octreotide and tetrandrine, alone and in combination, in portal hypertensive rats. Portal hypertension was induced by partial portal vein ligation. Portal hypertensive rats were allocated into one of the four groups: vehicle group (saline, 0.5 mL/day), octreotide group (100 microg/kg per 12 h), tetrandrine group (20 mg/kg per 12 h), and octreotide (100 microg/kg per 12 h) plus tetrandrine (20mg/kg per 12 h) group. Tetrandrine or saline was administered by gavage, and octreotide by subcutaneous injection. The drug was given for 8 consecutive days, starting 1 day before ligation and continuing onwards. Haemodynamic parameters were measured thereafter, using the radioactive microsphere method. The portal venous pressure and portal tributary blood flow were significantly reduced, while portal territory and renal vascular resistances were significantly enhanced, by octreotide, tetrandrine, or octreotide plus tetrandrine in portal hypertensive rats, compared with the vehicle group. Our results showed that long-term administration of octreotide, tetrandrine, or octreotide plus tetrandrine led to portal hypotensive effects in portal hypertensive rats, but octreotide alone exerted better anti-hyperdynamic effects compared with tetrandrine alone. A combination of octreotide and tetrandrine offered no major beneficial anti-hyperdynamic effects compared with octreotide alone.

Myofascial trigger points in intercostal muscles secondary to herpes zoster infection of the intercostal nerve

Chronic pain in the chest wall is a major complication after herpes zoster infection of intercostal nerves. It is usually difficult to control pain of such origin. Two cases are reported of postherpetic neuralgia after herpes zoster infection involving the intercostal nerves. Both patients had shooting, burning, aching, and localized pain in the muscle supplied by the involved intercostal nerves 1 to 3 months after onset. Compression palpation of a tender spot in one of these muscles induced a referred pain that followed the corresponding interspace, usually in the distal anterior direction. Local twitch responses could be elicited during injection of 0.5% or 1% lidocaine into one of these tender spots; the pain in the interspace was consistently eliminated immediately after injection. One patient had complete pain relief after three series of injections. The effect of pain relief for the other patient lasted for 1 to 2 weeks after the initial injection and lasted progressively longer (up to 2 months) after repeated injections. It appears that many of the tender spots formed in intercostal muscles after herpes zoster are myofascial trigger points that respond to injection with referred pain, local twitch responses, and immediate pain relief.

Dual infection with Ehrlichia chaffeensis and a spotted fever group rickettsia: a case report

Well-documented cases of simultaneous human infection with more than one tick-borne pathogen are rare. To our knowledge only two dual infections have been reported: simultaneous human infection with the agent of human granulocytic ehrlichiosis and Borrelia burgdorferi and simultaneous human infection with B. burgdorferi and Babesia microti (1-2). Rocky Mountain spotted fever has long been known to be endemic in North Carolina; cases of human ehrlichial infection were recognized there soon after Ehrlichia chaffeensis was recognized as an important cause of tick-borne disease in the southeastern United States. Because both Rocky Mountain spotted fever and ehrlichiosis are prevalent in North Carolina, occasional cases of simultaneous human infection by rickettsial and ehrlichial agents would not be surprising; however, no such cases seem to have been reported.

New dye-labeled terminators for improved DNA sequencing patterns

We have used two new dye sets for automated dye-labeled terminator DNA sequencing. One set consists of four, 4,7-dichlororhodamine dyes (d-rhodamines). The second set consists of energy-transfer dyes that use the 5-carboxy-d-rhodamine dyes as acceptor dyes and the 5- or 6-carboxy isomers of 4'-aminomethylfluorescein as the donor dye. Both dye sets utilize a new linker between the dye and the nucleotide, and both provide more even peak heights in terminator sequencing than the dye-terminators consisting of unsubstituted rhodamine dyes. The unsubstituted rhodamine terminators produced electropherograms in which weak G peaks are observed after A peaks and occasionally C peaks. The number of weak G peaks has been reduced or eliminated with the new dye terminators. The general improvement in peak evenness improves accuracy for the automated base-calling software. The improved signal-to-noise ratio of the energy-transfer dye-labeled terminators combined with more even peak heights results in successful sequencing of high molecular weight DNA templates such as bacterial artificial chromosome DNA.

Western immunoblotting analysis of the antibody responses of patients with human monocytotropic ehrlichiosis to different strains of Ehrlichia chaffeensis and Ehrlichia canis

In order to evaluate the relative sensitivity of the detection of antibodies against various antigenic proteins of Ehrlichia chaffeensis for the diagnosis of the emerging infectious disease human monocytotropic ehrlichiosis, Western immunoblotting was performed with 27 serum samples from convalescent patients with antibodies, as demonstrated by indirect immunofluorescence assay. Among 22 patients with antibodies reactive with the 120-kDa protein, 15 showed reactivity with the 29/28-kDa protein(s) and the proteins in the 44- to 88-kDa range. Two of the serum samples with this pattern reacted with the 29/28-kDa protein(s) of only the 91HE17 strain, and one sample reacted with only that of the Arkansas strain, indicating that the antibodies were stimulated by strain-specific epitopes. Overall, antibodies to the 29/28-kDa protein(s) were detected in only 16 patients' sera, suggesting that this protein is less sensitive than the 120-kDa protein. Two of 12 serum samples from healthy blood donors had antibodies reactive with the 120-kDa protein; one of these samples reacted also with the 29/28-kDa protein(s) of Ehrlichia canis, suggesting that unrecognized ehrlichial infection might have occurred, including human infection with E. canis. A high correlation between reactivity with the 120-kDa protein by Western immunoblotting and the recombinant 120-kDa protein by dot blot supports the potential usefulness of this recombinant antigen in diagnostic serology.

Referred pain elicited by palpation and by needling of myofascial trigger points: a comparison

OBJECTIVE

To investigate the occurrence of referred pain (ReP) elicited by palpation (Pal-ReP) or by needle injection (Inj-ReP) of myofascial trigger point (MTrP), and to assess the correlated factors, including the pain intensity of an active MTrP and the occurrence of local twitch response (LTR).

DESIGN

Correlational study.

PATIENTS

Ninety-five patients who were treated with MTrP injections.

INTERVENTION

MTrP injections.

MAIN OUTCOME MEASURE

Pain intensity of MTrP and occurrence of Pal-ReP, Inj-ReP, and LTR.

RESULTS

Both Pal-ReP and Inj-ReP were elicited in 53.9% of MTrPs, Inj-ReP, but not Pal-ReP, was elicited in 33.7% of MTrPs. Both Pal-ReP and Inj-ReP were unobtainable in 12.3% of MTrPs. The occurrence of ReP was significantly correlated to the pain intensity of active MTrP and the occurrence of LTR.

CONCLUSION

ReP could be elicited more frequently by needling than by palpation. The frequency of occurrence in ReP mainly depends on pain intensity of an active MTrP.

Phosphorylation can modulate the association of different sets of RNA binding proteins with the Vg1 localization signal RNA

As assayed by both in vivo and in vitro UV-crosslinking techniques, four RNA binding proteins, with apparent molecular weight of 56, 54, 42, and 40 kilodaltons, associated specifically with the Xenopus Vg1 mRNA localization signal (LS) RNA. The 56 and 54 kD proteins were assigned as the masking proteins described previously, on the basis of their thermal stability and the effect of phosphorylation on RNA binding activity. The 42 and 40 kD proteins associated with the LS RNA at a lower extract concentration than the masking proteins did in vitro. Dephosphorylation will eliminate the RNA binding activities of all four proteins. However, either raising the extract concentration or phosphorylating the extract by the catalytic domain of protein kinase A had opposite effects on the crosslinking efficiencies of these two sets of RNA binding proteins. Phosphorylation might regulate this protein exchange process in vitro.

Association of Sauropus androgynus and bronchiolitis obliterans syndrome: a hospital-based case-control study

In late April 1995, an outbreak of a poorly defined respiratory illness related to the ingestion of leaves of Sauropus androgynus was observed in southern Taiwan. To further evaluate the association between S. androgynus and bronchiolitis obliterans syndrome, a hospital-based case-control study was conducted with one case group and three different control groups at Veterans General Hospital-Kaohsiung between April and September 1995. A total of 54 cases (50 females, 4 males), 54 age- and sex-matched neighborhood controls, 54 matched routine physical check-up controls, and 54 matched self-referred patron controls (who had ingested S. androgynus yet without obstructive physiology) were interviewed for clinical symptoms, history of S. androgynus consumption, and potential confounding factors. All 54 cases (100%) ingested S. androgynus compared with only five (9%) neighborhood controls (matched odds ratio (OR) incalculable, p < 0.001) and two (4%) physical check-up controls (matched OR incalculable, p < 0.001). In the univariate analysis of 54 cases and 54 self-referred patron controls, factors associated with an increased risk of bronchiolitis obliterans syndrome were methods of food preparation (uncooked juice vs. stir fried or boiled dishes, matched OR 10.3 (95% confidence interval (CI) 1.3-84.4)); preparer of the S. androgynus-containing food (vendor only vs. patient only or patient plus vendor, matched OR 2.8 (95% CI 1.1-7.1)); total S. androgynus consumption quantity (> 4,500 vs. 413-2,063 g, matched OR 10.0 (95% CI 1.9-53.0)); duration of consumption (> 45 vs. 6-24 days, matched OR 2.1 (95% CI 1.2-3.8)); and midterm interruption (< 2 vs. 2-5 days per week, matched OR 2.6 (95% CI 1.1-6.1)). Additionally, multiple conditional logistic regression analysis of cases and self-referred patron controls revealed that a larger total amount of S. androgynus consumption, preparation of S. androgynus food without cooking, and ingesting S. androgynus food prepared by a vendor were the significant risk factors associated with bronchiolitis obliterans syndrome.

Genetic and antigenic diversity of Ehrlichia chaffeensis: comparative analysis of a novel human strain from Oklahoma and previously isolated strains

A new Ehrlichia strain, designated as Ehrlichia chaffeensis, Sapulpa strain, was isolated from a patient from Oklahoma with severe ehrlichiosis. Isolation of the ehrlichial pathogen was achieved by inoculating patient blood onto HEL cells and DH82 cells. Antigenic properties of the new isolate were characterized with monoclonal antibodies, homologous patient serum, and polyclonal rabbit serum by Western immunoblotting. The results showed antigenic differences and protein size variation of Sapulpa strain compared with the other 2 strains of E. chaffeensis. Sequencing of the 16S rRNA gene showed 100% identity to that of E. chaffeensis, strain 91HE17. Polymerase chain reaction and sequencing of DNA homologous to the 120-kDa protein gene of E. chaffeensis, Arkansas strain, showed that this gene of Sapulpa strain was smaller than that of Arkansas strain and contained a repeat region with three tandem repeat units.

Prognostic factors in patients with bulky stage IB or IIA cervical carcinoma undergoing neoadjuvant chemotherapy and radical hysterectomy

All patients with bulky (> or =4 cm) Stage Ib or IIa cervical carcinoma treated at Chang Gung Memorial Hospital between August 1988 and December 1991 using a strategy of neoadjuvant chemotherapy with cisplatin, vincristine, and bleomycin and radical hysterectomy were reviewed. Fifty-nine evaluable patients received 1 to 3 courses of chemotherapy, and 51 underwent subsequent hysterectomy. The remaining 8 patients, not completing planned surgery, were treated with definitive radiotherapy. The overall clinical response rate was 81.4% (48/59) with 18.6% complete response. Clinical response to chemotherapy was not different by stage, histologic type, tumor size, level of squamous cell carcinoma antigen, or DNA ploidy. However, tumors with DNA indices (DI) greater than 1.3 were associated with higher clinical response rates than tumors with DI < or = 1.3 (P = 0.043). Histologically proven pelvic node metastases was noted in 18.5% (10/54) who had laparotomy. Concomitant pregnancy and more than one node metastases had significant adverse influence on recurrence and death. The 5-year survival rate of those patients who received hysterectomy was 80.3%, while only 1 of the 8 patients without hysterectomy survived. Of the 7 patients received hysterectomy despite clinical poor response, only 2 had node metastases and 3 died, whereas all the 4 patients deterred hysterectomy for poor response died. This study demonstrates the value of DNA flow cytometry in predicting chemosensitivity. However, with a DI cutoff at 1.3, only 29.2% patients could be selected. Further studies are necessary to find additional indicators that predict histological response to select better candidates for this approach and to determine optimal adjunctive treatment in case that poor prognostic features are found.

Comments on "A Petri net model for temporal knowledge representation and reasoning"

Yao (1994) has presented a unified time Petri net model (TPN) for temporal knowledge representation and reasoning, where the TPN model presented has a good contribution to the aspect of temporal knowledge representation and reasoning. However, there are a number of errors which should be corrected. The purpose of the paper is to identify these errors, and the corrections provided permit the readers who have been confused by the errors to gain a better understanding of the good ideas presented.

The role of DNA flow cytometry in borderline malignant ovarian tumors

BACKGROUND

The role of flow cytometric DNA analysis in predicting prognosis of patients with borderline malignant ovarian tumors has been controversial.

METHODS

Fifty cases of patients with borderline malignant ovarian tumors were analyzed by histology and by flow cytometry on paraffin embedded tissue. Multiple tissue blocks and serial sections were analyzed for each tumor. The results of DNA analysis were correlated to clinicopathologic data.

RESULTS

DNA aneuploidy was demonstrable in 4 cases (8%) when the most atypical section was analyzed. The overall rate of aneuploidy was 14% if additional blocks and serial sections were studied. Two patients died from tumor. One of the two patients had an initial diagnosis of Stage IIc mucinous borderline tumor with DNA indices (DI) of 1.12, 1.42, and 2.04. She had a recurrence in the contralateral ovary 1 year later (DI = 1.83), and a second frankly malignant recurrence diffusely in peritoneum (DI = 1.89). The other patient had an initial diagnosis of Stage IIIc mucinous borderline ovarian tumor with pseudomyxoma peritonei. DNA diploidy was obtained in all of the samples from the primary tumor. An aneuploid peak (DI = 1.28) was demonstrated in only one serial section of the peritoneal implants. Of the other 5 patients who had aneuploid histograms but were disease-free, the DNA indices were 1.35, 1.14/1.18, 1.15, 1.20, and 1.31 and were demonstrable only in either 1 or 2 of the blocks or unproven on serial sections. All patients with diploid-peridiploid tumors were alive and disease free.

CONCLUSIONS

Reproducible DNA aneuploidy of high DI may be predicting a poor outcome, whereas the significance of inconsistently reproducible aneuploidy of low DI remains to be determined. Further studies of prospective DNA analysis with adequate sampling are necessary to define the role of flow cytometry in patients with borderline malignant ovarian tumors.

Study of isometric lifting strength in normal Chinese adults

The purposes of this study were to describe norms of isometric lifting strength for healthy Chinese adults and to investigate the effects of age, gender, body weight, and body height on lifting strength. Three types of lifting (i.e., arm, back, and leg lifting) were measured in a sample of 350 Chinese adults (172 men and 178 women) aged between 20 and 81 years. A Force Evaluation and Testing System (FET 5000) was used for strength measurements with three standard lifting positions. The average of two trials for each lifting strength test was used as the subjects' test score. The results showed that the greatest strengths for both sexes exist aged between late 20's and early 30's, with a general decline following thereafter. The magnitude of strength decline with age was most prominent in leg lifting strength among all lifting patterns. Males were stronger than females in all lifting patterns among the different age groups. All of the lifting strengths studied correlated positively with gender, body weight, and body height, and negatively with age in the analyses of simple correlation coefficients. In addition, stepwise multiple regression analyses showed that sex, age and body weight were most predictive of all types of lifting strengths. Body height was an effective predictor of back lifting strength. These findings and the establishment of data base can provide therapists with an objective evaluation regarding lifting strength of individuals for clinical use.

Gallbladder function and recurrent stones of the biliary tract in patients after endoscopic sphincterotomy

BACKGROUND

Change in gallbladder function may occur in patients with an intact gallbladder after endoscopic sphincterotomy (EST). This study was designed to evaluate the factors influencing gallbladder filling after EST and the correlation between gallbladder function and stone recurrence.

METHODS

Sixty Chinese patients with symptomatic choledocholithiasis and an intact gallbladder received EST to clear the bile ducts. They were further investigated with sphincter of Oddi manometry (SOM), quantitative cholescintigraphy (QC), and long-term clinical follow-up.

RESULTS

Fifty-six of the 60 patients in the study group were confirmed to have a loss of sphincteric function by SOM. QC showed normal gallbladder filling in 35 of these patients and delayed or non-filling in 21 patients. A significantly higher incidence of normal gallbladder filling occurred in patients with juxtapapillary diverticulum than in those without (P < 0.02), but preexisting cholecystolithiasis had no effect on it. During the follow-up period (median, 32 months: range, 9-54 months) 10 of 56 patients developed recurrent choledocholithiasis. There was no correlation between the status of gallbladder filling, preexisting cholecystolithiasis, and recurrent stones, but 9 of the 10 patients with recurrent stones had a juxtapapillary diverticulum. Repeated endoscopic treatment was satisfactory in eight patients, and only two patients received cholecystectomy.

CONCLUSIONS

EST does not alter gallbladder function in most patients. Juxtapapillary diverticulum may facilitate gallbladder filling after EST, but it is also a possible factor for recurrent choledocholithiasis.

Analysis and ultrastructural localization of Ehrlichia chaffeensis proteins with monoclonal antibodies

Ehrlichia chaffeensis, an obligately intracellular bacterium with tropism for monocytes, is the etiologic agent of human monocytic ehrlichiosis. To determine the nature and ultrastructural location of E. chaffeensis antigens, monoclonal antibodies (MAbs) to E. chaffeensis were developed. The MAbs were used for immunofluorescence and Western immunoblotting analysis of the antigens of density gradient-purified ehrlichiae. Monoclonal antibody 6A1 recognized an epitope of a 30-kD protein. This antibody reacted with a strain-specific epitope of E. chaffeensis, Arkansas strain, and did not cross-react with any other ehrlichia tested. Monoclonal antibodies 3C7 and 7C1-B recognized Arkansas strain proteins of 30 and 29 kD and reacted with E. chaffeensis (strain 91HE17) proteins of 31 and 29 kD and an E. canis protein of 30 kD. Lack of reactivity of these two MAbs with E. sennetsu and E. risticii suggests that the epitope is group-specific. Monoclonal antibody 5D11 recognized a 58-kD protein of both strains of E. chaffeensis as well as E. canis, apparently a group-specific, conformation-independent epitope. Monoclonal antibody 7C1-C reacted with 58- and 88-kD proteins of both the Arkansas and 91HE17 strains. Trypsin treatment destroyed the reactivity of E. chaffeensis antigens with all the MAbs when tested by Western immunoblotting, indicating that these antigens are proteins with trypsin-sensitive epitopes. Immunoelectron microscopy of negatively stained intact E. chaffeensis organisms showed that the 30- and 29-kD proteins are present on the surface of the ehrlichial cell wall along with the previously localized 28-kD protein.

Ligand interactions with E-selectin. Identification of a new binding site for recognition of N-acyl aromatic glucosamine substituents of sialyl Lewis X

Several N-acylglucosamine derivatives of sialyl Lewis X (1-3) were prepared using a combined chemical enzymatic approach and evaluated as an inhibitor of E-selectin-mediated cellular adhesion. Compounds with aromatic functionality, 1 and 2, were found to be 3-10 times more potent than the N-acetyl derivative (14) in an ELISA E-selectin cell adhesion assay. Conformational analysis with NMR indicated that the sialyl Lewis x domain of 1 retained the conformation of the N-acetyl derivative (14) despite the presence of the N-naphthamido group. The dramatic order of magnitude increase in potency of these monovalent structures can be utilized to design more potent selectin-based cell adhesion inhibitors.

Effect of parathyroid hormone on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized rats

The purpose of the study was to investigate the effects of parathyroid hormone (PTH) infusion on antioxidant enzyme activity and lipid peroxidation of erythrocytes in five-sixths nephrectomized (Nx) rats. Five-sixths Nx rats had a higher osmotic fragility in red blood cells (RBC). Thyroparathyroidectomy (TPTX) effectively decreased the abnormality of osmotic fragility in RBC in Nx rats. PTH infusion in Nx-TPTX rats markedly increased the osmotic fragility in RBC. Total glutathione was measured by using the enzyme-recycling method. We found elevated glutathione levels in RBC of five-sixths Nx rats, but this elevation could be inhibited by TPTX and recovered by PTH infusion in Nx-TPTX rats. Five-sixths Nx rats had a lower glutathione peroxidase activity in RBC, but TPTX or PTH infusion was not found to alter the decrease of the glutathione peroxidase activity in RBC of five-sixths Nx rats. These rats had a higher activity in RBC superoxide dismutase as compared with sham-operated controls (p < 0.05), but the higher activity in RBC superoxide dismutase in Nx rats had been inhibited by TPTX. PTH infusion recovered the higher activity in RBC superoxide dismutase in five-sixths Nx-TPTX rats. Nx rats were not found to alter the activity of catalase in RBC. Neither could TPTX or PTH infusion in Nx rats influence the activity of catalase in RBC. A high lipid peroxidation in RBC was found in five-sixths Nx rats, namely, increased formation of malondialdehyde (MDA) in RBC had been induced to produce lipid peroxidation by H2O2, but neither TPTX nor PTH infusion could inhibit or enhance the increase of lipid peroxidation in RBC of Nx rats. These results indicate that PTH infusion did not increase the susceptibility to lipid peroxidation in RBC of five-sixths Nx rats. Thus, the increased osmotic fragility in RBC induced by PTH infusion may not result from the reduction in the RBC defense mechanism against free radical toxicity.

The impact of endoscopic variceal ligation on the pressure of the portal venous system

BACKGROUND/AIMS

Endoscopic variceal ligation is a viable substitute for injection sclerotherapy. It is still not known how endoscopic variceal ligation may influence the portal venous system. To clarify this issue we investigated the impact of endoscopic variceal ligation on the pressure of the portal venous system.

METHODS

Twenty-nine patients with a history of esophageal variceal bleeding but without ascites were enrolled. All had cirrhosis; 63% of them were post-hepatitic. Ligation was performed at intervals of 2-3 weeks until all the varices were obliterated. Portal venograms were performed before institution of ligation and after variceal obliteration to assess venographic findings and pressure changes. The pressures of the main portal vein, splenic vein and superior mesenteric vein were recorded.

RESULTS

Twenty-five patients completed the study. A mean of 4.4 sessions (range: 2-7) of ligation over a period of 2 months was needed. Seventeen (68%) patients experienced elevated pressure and eight (32%) patients reduced pressure after ligation. Mean (median) pressure changes were as follows: portal venous pressure, 26.5 +/- 4.7 (25.0) mmHg vs. 28.2 +/- 7.2 (28.0) mmHg (p > 0.05); splenic venous pressure, 28.2 +/- 4.9 (26.0) mmHg vs. 29.0 +/- 6.8 (29.0) mmHg (p > 0.05); superior mesenteric venous pressure, 28.4 +/- 6.0 (27.0) mmHg vs. 29.5 +/- 7.0 (29.0) mmHg (p > 0.05). Five patients (20%) experienced rebleeding before variceal obliteration; all of them presented elevated portal pressures after variceal obliteration. Among the eight patients with decreased portal pressure, seven (87%) had other major collaterals apart from esophageal varices, compared to three out of the 17 (18%) patients with elevated portal pressure who had other major collaterals (p < 0.01).

CONCLUSIONS

Among patients receiving endoscopic variceal ligation, 68% experienced elevated portal pressure, while 32% had decreased portal pressure. Elevation of portal pressure after variceal ligation may be an important factor in variceal rebleeding. The presence of other major collaterals apart from esophageal varices may be responsible for the decrease in portal pressure after obliteration of esophagel varices.