Malignant ventricular arrhythmias induction by programmed electrical stimulation of the right ventricular outflow tract only during type 1 Brugada ECG maximization.

OBJECTIVE: The role of electrophysiology study in Brugada syndrome (BS) sudden cardiac death risk stratification remains controversial and seems to depend on the phenotypic expression of the channelopathy. Ajmaline has a key role in the diagnosis of BS. We observed that programmed electrical stimulation (PES) of the right ventricular outflow tract (RVOT), only when type 1 BS ECG is unmasked by ajmaline administration, induces ventricular arrhythmias. CASE REPORT: We describe a case of ventricular fibrillation induction by PES of the RVOT when type 1 BS ECG is revealed by ajmaline, in a patient with a baseline dynamic intermittent type 1 and 2 BS ECG. CONCLUSIONS: The heterogeneous clinical presentations of BS are due to the underlying mechanisms. PES of the RVOT during positive ajmaline test maximizes the channelopathy and therefore sudden cardiac death risk-stratification in BS.

Ventricular fibrillation induction and diffuse abnormal ST-segment response to ajmaline in a patient with apparent pre-existing dynamic right bundle branch block.

OBJECTIVE: ST-segment elevation in the right precordial electrocardiography (ECG) leads in Brugada syndrome (BS) can be unmasked by class I anti-arrhythmic drugs (sodium channel blockers) administration. It is still debated whether this ECG pattern is better explained by abnormal repolarization or ventricular conduction and depolarization. Conduction diseases can conceal type 1 BS-like ECG in standard V1-V3 leads. ECG alterations were found also in alternative leads. The role of electrophysiology study (EPS) in sudden cardiac death risk stratification remains controversial, and could depend on the phenotypic expression of the cardiac sodium channels disease. CASE REPORT: We describe unmasked diffuse J-point and ST-segment anomalies in peripheral and precordial ECG leads and ventricular fibrillation (VF) induction by EPS after ajmaline administration in a patient with pre-existing atypical right bundle branch block (RBBB) concealing subtle anomalies in standard V1-V3 leads. RBBB was influenced by the underlying BS-like ECG associating repolarization anomaly and pre-existing conduction disease. EPS induced VF when RBBB was associated with BS-like ECG, and failed to induce VF when RBBB was present alone. CONCLUSIONS: BS phenotype heterogeneity requires further studies to improve the knowledge of its pathophysiological mechanisms associated with conduction diseases in order to better identify an individual therapy and prognostic stratification.

Catheter ablation of atrial tachycardia after interatrial defect repair with patch apposition.

A 54-year-old woman with history of septal atrial mixoma surgically treated and drug-refractory supraventricular tachyarrhythmia underwent catheter ablation of macro-reentry areas near the pericardial patch placed to repair an interatrial defect. The use of ablative therapy has been successful to cure this arrhythmia.

Assessment of right ventricular function by strain rate imaging in chronic obstructive pulmonary disease.

The purpose of the current study was to compare right ventricular (RV) myocardial wall velocities (tissue Doppler imaging) and strain rate imaging (SRI) parameters with conventional echocardiographic indices evaluating RV function in chronic obstructive pulmonary disease (COPD) patients. In total, 39 patients with COPD and 22 healthy subjects were included in the current study. Seventeen patients had pulmonary artery pressure <35 mmHg (group I) and 22 patients had pulmonary artery pressure >35 mmHg (group II). Tissue Doppler imaging, strain and strain rate (SR) values were obtained from RV free wall (FW) and interventricular septum. Respiratory function tests were performed (forced expiratory volume in one second/vital capacity (FEV(1)/VC) and carbon monoxide diffusion lung capacity per unit of alveolar volume (D(L,CO)/V(A))). Strain/SR values were reduced in all segments of group II patients compared with group I patients and controls with lowest values at basal FW site. A significant relationship was shown between peak systolic SR at basal FW site and radionuclide RV ejection fraction. A significant relationship was shown between peak systolic SR at basal FW site and D(L,CO)/V(A) and FEV(1)/VC. In conclusion, in chronic obstructive pulmonary disease patients, strain rate imaging parameters can determine right ventricular dysfunction that is complementary to conventional echocardiographic indices and is correlated with pulmonary hypertension and respiratory function tests.

Impact of intracoronary aspiration thrombectomy during primary angioplasty on left ventricular remodelling in patients with anterior ST elevation myocardial infarction.

OBJECTIVE: To evaluate prospectively the impact on left ventricular (LV) remodelling of an intracoronary aspiration thrombectomy device as adjunctive therapy in primary percutaneous coronary intervention (PCI) in patients with anterior ST elevation myocardial infarction (STEMI). METHODS: 76 consecutive patients with anterior STEMI (65.3 (11.2) years, 48 men) were randomly assigned to intracoronary thrombectomy and stent placement (n = 38) or to conventional stenting (n = 38) of the infarct related artery. Each patient underwent transthoracic echocardiography immediately after PCI and at six months. At the time of echocardiographic control, major adverse cardiovascular events (MACE) in terms of death, new onset of myocardial infarction, and hospitalisation for heart failure were also evaluated. RESULTS: After a successful primary PCI, patients in the thrombectomy group achieved a higher rate of post-procedure myocardial blush grade 3 (36.8% v 13.1%, p = 0.03) and effective ST segment resolution at 90 minutes (81.6% v 55.3%, p = 0.02). Six months after the index intervention, 19 patients (26.8%) developed LV dilatation, defined as an increase in end diastolic volume (EDV) >or= 20%: 15 in the conventional group and four in the thrombectomy group (p = 0.006). Accordingly, at six months patients treated conventionally had significantly higher end systolic volumes (82 (7.7) ml v 75.3 (4.9) ml, p < 0.0001) and EDV (152.5 (18.1) ml v 138.1 (10.7) ml, p < 0.0001) than patients treated with thrombectomy. No differences in cumulative MACE were observed (10.5% in the conventional group v 8.6% in the thrombectomy group, not significant). CONCLUSION: Compared with conventional stenting, adjunctive aspiration thrombectomy in successful primary PCI seems to be associated with a significantly lower incidence of LV remodelling at six months in patients with anterior STEMI.

Noninvasive assessment of coronary artery stenoses by multidetector-row spiral computed tomography: comparison with conventional angiography.

BACKGROUND: Coronary artery disease (CAD) is the most common cause of hospitalization and mortality in many industrialized countries. We analysed the diagnostic accuracy of multi-detector row spiral computed tomography (MDCT) in determining mid- to high-grade coronary artery stenoses (> 50%). METHODS: Sixty-nine patients with suspected CAD were referred to MDCT coronary angiography. Patients with a heart rate above 60 bpm received 20-40 mg propranol before the scan. The left main (LM), the left anterior descending artery (LAD), the first diagonal branch (D1), the right coronary artery (RCA) and the proximal tract of the circumflex artery (LCX) were independently evaluated by two blinded observers and screened for > 50% stenoses. The mean values of MDCT coronary narrowings assessed by two observers were compared to quantitative coronary angiography. RESULTS: MDCT correctly detected 95 of 123 coronary lesions (sensitivity 77.2%) and absence of stenoses was correctly identified in 388 of 426 segments (specificity 91%). The sensitivity for the LM, LAD, RCA and the proximal tract of LCX was 100%, 86.5%, 69.8% and 80% respectively. Classification of patients as having 1-vessel, 2-vessels, 3-vessels or left main disease was accurate in 75.4% (46/61) of patients. CONCLUSIONS: MDCT technology, combined with heart rate control, allows reliable noninvasive detection of hemodynamically significant CAD.

Prominent crista terminalis mimicking a right atrial mixoma: cardiac magnetic resonance aspects.

A 68-year-old woman came to our observation with a clinical history of isolated systolic hypertension poorly controlled by the combination of ramipril 5 mg and hydrochlorothiazide 12.5 mg o.d. The ECG showed sinus rhythm with heart rate of 68 beats per minute and signs of left ventricular hypertrophy without strain. Further investigation included an echocardiogram that showed normal left and right cavities and normal cardiac valves. At the level of the posterior wall of the right atrial (RA) an apparent smooth, bean-like tumor, having a thin pedicle, was identified as a RA mixoma. Cardiac MRI was requested and showed in two sequential slices a muscular ridge, identified as a prominent crista terminalis. Some para-physiological structures sited in the RA may have the appearance of tumors, as crista terminalis, Eustachian valve extending into the RA chambers and Chiari network. The multiplain projections of MRI allow the cardiologist to identify the presence of intracardiac masses and to make a differential diagnosis between neoplasms and variant anatomic structures.

Effect of extent of resection on intestinal muscle adaptation.

The response of intestinal muscle to resection has received less attention than mucosal adaptation but may be important in relation to altered motility and improved intestinal absorption. Our aim was to determine the effect of extent of resection on intestinal muscle adaptation. Distal resections of 25% (n = 5), 50% (n = 5), and 75% (n = 5) of the intestine were performed. Transverse intestinal sections were taken at resection and 12 weeks later to evaluate changes in mucosa and circular and longitudinal muscle thickness. Muscle cell number and size and muscle length were also measured. Mucosal thickness increased (P < 0.05) after all resections, (1007 +/- 253 microns vs 1259 +/- 181 microns, 25%; 1019 +/- 191 microns vs 1366 +/- 293 microns, 50%; and 927 +/- 88 microns vs 1432 +/- 213 microns, 75%). Longitudinal muscle thickness (169 +/- 35 microns vs 254 +/- 45 microns, 50%; 207 +/- 71 microns vs 353 +/- 103 microns, 75%) and length (180 +/- 10 cm vs 203 +/- 16 cm, 50%; 90 +/- 16 cm vs 110 +/- 21 cm, 75%) increased (P < 0.05) following 50% and 75% resections but not after a 25% resection. Circular muscle length increased after 75% resection alone (4.4 +/- 0.2 cm vs 5.8 +/- 0.4 cm, P < 0.05). There was no significant change in circular muscle thickness after any resection. Muscle cell size and number per unit area were unchanged in all groups. We concluded that: (1) Intestinal muscle adapts after intestinal resection and this response is related to the extent of resection; in contrast, mucosal adaptation was evident following even the least extensive resection. (2) Increased thickness and length of the longitudinal muscle layer are the most prominent changes. (3) This increased muscle thickness results from hyperplasia rather than hypertrophy.

Regional variation in canine intestinal muscle mass and function.

Our aim was to investigate the contribution of variations in intestinal muscle morphology or function to regional differences in motor properties in vivo. We quantitated intestinal muscle thickness and surface area along the canine gut and compared the in vitro contractile properties of the jejunum and ileum. The thickness and cross-sectional surface area of both circular and longitudinal muscle demonstrated a parabolic distribution along the intestine, with the greatest values occurring in the proximal and distal regions. The terminal ileum had the greatest circular (885 +/- 194 microns) and longitudinal muscle (367 +/- 135 microns) thickness. Circular muscle was 2.5-3 times thicker than longitudinal muscle at all points. Passive tension was similar in muscle strips from the mid-jejunum, mid-ileum, and terminal ileum (2.8 +/- 0.8, 2.5 +/- 0.4, and 2.3 +/- 0.8 vs 2.5 +/- 0.5, 1.9 +/- 0.5, and 2.8 +/- 1.0, longitudinal and circular, respectively). Active and total tension, however, were significantly greater in longitudinal than circular muscle in mid-jejunum (active; 8.5 +/- 1.4 vs 5.6 +/- 1.2, P < 0.05 and total 11.3 +/- 1.7 vs 8.1 +/- 1.2) and in mid-ileum (active 9.5 +/- 1.6 vs 5.8 +/- 1.2 and total 12.0 +/- 1.6 vs 7.7 +/- 1.2). Values for each layer were similar in both sites. In contrast, in the terminal ileum, longitudinal and circular muscle strips demonstrated similar active (10.1 +/- 1.7 vs 9.0 +/- 2.7, NS) and total tension (12.4 +/- 2.0 vs 11.9 +/- 3.4, NS). Dose-response curves to carbachol (10(-8)-10(-2) M) were similar in all these regions. We conclude (1) there are regional variations in muscle mass but contractile properties are similar in jejunum and ileum; and (2) the unique motor properties of the terminal ileum may be related more to differences in muscle morphology and neural input than intrinsic function.

Estrone sulfate-sulfatase and 17 beta-hydroxysteroid dehydrogenase activities: a hypothesis for their role in the evolution of human breast cancer from hormone-dependence to hormone-independence.

The evaluation of estrogens (estrone, estradiol, and their sulfates) in the breast tissue of post-menopausal patients with breast cancer indicates high levels, particularly of estrone sulfate (E1S) which is 15-25 times higher than in the plasma. Breast cancer tissue contains the enzymes necessary for local synthesis of estradiol and it was demonstrated that, despite the presence of the sulfatase and its messenger in hormone-dependent and hormone-independent breast cancer cells, this enzyme operates particularly in hormone-dependent cells. Different progestins: Nomegestrol acetate, Promegestone, progesterone, as well as Danazol, can block the conversion of E1S to E2 very strongly in hormone-dependent breast cancer cells. The last step in the formation of estradiol is the conversion of E1 to this estrogen by the action of 17 beta-hydroxysteroid dehydrogenase. This activity is preferentially in the reductive direction (formation of E2) in hormone-dependent cells, but oxidative (E2-->E1) in hormone-independent cells. Using intact hormone-dependent cells it was observed that Nomegestrol acetate can block the conversion of E1 to E2. It is concluded, firstly, that in addition to ER mutants other factors are involved in the transformation of hormone-dependent breast cancer to hormone-independent, this concerns the enzymatic activity in the formation of E2; it is suggested that stimulatory or repressive factor(s) involved in the enzyme activity are implicated as the cancer evolves to hormone-independence; secondly, different drugs can block the conversion of E1S to E2. Clinical trials of these "anti-enzyme" substances in breast cancer patients could be the next step to investigate new therapeutic possibilities for this disease.

Transformation of estrone and estradiol in hormone-dependent and hormone-independent human breast cancer cells. Effects of the antiestrogen ICI 164,384, danazol, and promegestone (R-5020).

Using different hormone-dependent (MCF-7, T-47D) and hormone-independent (MDA-MB-231, Hs-578S, MDA-MB-436) human breast cancer cells, the interconversion estrone (E1)<-->estradiol (E2) was explored. The data show very clearly that in the hormone-dependent cells the tendency is to form E2 after incubation with E1, whereas after incubation with E2 most of this estrogen remains unchanged. In the hormone-independent cells, in contrast most of E1 remains E1, while E2 is converted into E1. The tendency of the reductive<-->oxidative direction is supported by the analysis of estrogens in the culture medium. To explore the possible action of different drugs on the 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) activity, it was observed that the potent antiestrogen ICI 164,384 inhibits the conversion of E1 to E2, while a lesser effect is observed with Danazol and only weak inhibition is obtained with the progestagen Promegestone (R-5020). It is concluded that the orientation of 17 beta-HSD activity for the interconversion E1<-->E2 in hormone-dependent and -independent cells is related to the hormonal status of the cells.

Effect of triptorelin (Decapeptyl) combined with heparin on estradiol levels in MCF-7 mammary cancer cells after incubation with estrone sulfate.

The effects of triptorelin (Decapeptyl) and heparin, alone or in combination, on the intracellular concentration of estradiol (E2) after incubation of estrone sulfate (E1S) with the MCF-7 mammary cancer cells was investigated. Although heparin (10 mg/l culture medium) or Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) did not affect the levels of radioactive E2 after incubation with [3H]E1S, the combination of Decapeptyl and heparin significantly decreased the radioactive uptake and the intracellular concentrations of [3H]E2. In the absence of Decapeptyl and heparin incubations with E1S, the resulting E2 concentration (in nmol/kg DNA +/- SD) was 558 +/- 44; after heparin (10 mg/l) plus Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) the values were 389 +/- 55 and 165 +/- 18, respectively. It is concluded that Decapeptyl with heparin can decrease very significantly the conversion of E1S to E2 in MCF-7 cells, an observation that suggests new possibilities for the control of E2 in hormone-dependent breast cancer.

Action of danazol on the conversion of estrone sulfate to estradiol and on the sulfatase activity in the MCF-7, T-47D and MDA-MB-231 human mammary cancer cells.

In the present studies the action of Danazol on the conversion of estrone sulfate (E1S) to estradiol (E2) as well as on the sulfatase activity in the MCF-7 and T-47D, hormone-dependent, and MDA-MB-231, hormone-independent, mammary cancer cell lines was explored. Using intact cells we observed that Danazol blocks very significantly the radioactivity uptake and the conversion of [3H]E1S to E2 in all the cells studied. In particular, a very strong effect (85% decrease of these parameters versus the control values) is observed in the T-47D cells. In another series of studies using cell homogenates it is observed that Danazol inhibits the sulfatase activity in all these cell lines. The effect of Danazol is dose-dependent and significant from a concentration of 1 microM. At concentrations of 8 microM E1S, 10(-5) M Danazol, the inhibition of sulfatase activity is 38% in MCF-7, 36% in MDA-MB-231, and 27% in T-47D cells. Analysis by Lineweaver-Burk plot shows that the inhibitory effect is competitive. As E1S is one of the main sources of E2 in human mammary tumors, the present data could open new possibilities for therapeutic applications in hormone-dependent breast cancer.

Somatostatin analogue inhibits intestinal regeneration.

Somatostatin analogue octreotide inhibits intestinal absorption and motility but its effect on epithelial cell migration and proliferation remains unclear. Our aim was to determine the effect of octreotide on parameters of intestinal regeneration, including epidermal growth factor (EGF)-induced changes. Thirty rabbits had full-thickness ileal defects patched with cecal serosa surface. Group 1 were controls. Groups 2 and 3 received 100 micrograms and 1000 micrograms, respectively, of subcutaneous octreotide daily. Group 4 received EGF at 1.5 micrograms/kg per hour via subcutaneous miniosmotic pump, and group 5 received both octreotide (1000 micrograms/d) and EGF (1.5 micrograms/kg per hour). Octreotide at 100 micrograms/d did not inhibit epithelial cell migration or proliferation at 7 days. Octreotide at 1000 micrograms/d inhibited normal but not EGF-stimulated cell migration. Octreotide decreased EGF-stimulated but not normal proliferation. Octreotide impairs epithelial cell migration in a dose-dependent manner. Octreotide inhibits EGF-stimulated proliferative activity but not EGF-stimulated migration. Prolonged administration of octreotide may adversely affect normal and adaptive intestinal regeneration by both direct and indirect effects.

Comparison of techniques for harvesting enterocytes for transplantation.

Selective enterocyte transplantation is a potential alternative to small intestinal transplantation for treatment of the short bowel syndrome. Our aim was to compare chelation and enzymatic methods of isolating enterocytes with respect to initial cell yield and characteristics and in vitro growth. Enterocytes were harvested from adjacent ileal segments in 35 rabbits using chelation with EDTA and warm trypsinization. Determinations were made of initial viability by trypan blue exclusion, cell yield, and proportion of intact crypts. Cells (5 x 10(6)) were seeded in growth media into culture vessels. Cell attachment was estimated by measuring cells liberated by Dispase at 24 hr. In vitro growth was assessed at 14 and 28 days. Although total cell yield (15.0 +/- 9.9 vs 12.5 +/- 8.3 x 10(6) cells/cm) and intact crypts were similar, the trypsin technique resulted in cells with higher initial viability (86 +/- 7 vs 71 +/- 18%, P < 0.05). Cell attachment (7 +/- 8 vs 8 +/- 4%) and enterocyte disaccharidase activity were similar using both techniques. While the number of epithelial cell growth foci was not significantly different at 14 days, there was significantly greater surface coverage on both plain (44 +/- 20% vs 1 +/- 0%, P < 0.05) and Matrigel-coated (80 +/- 14 vs 16 +/- 25%, P < .05) vessels at 28 days with trypsin-isolated cells. Trypsinization resulted in a cell population which had a higher percentage of viable cells but a similar proportion of intact crypts and differentiated cells compared to those resulting from the chelation technique. Trypsin-liberated cells had greater capacity for in vitro growth particularly on Matrigel-coated surfaces.(ABSTRACT TRUNCATED AT 250 WORDS)

Gas chromatographic-mass spectrometric determination of plasma selegiline using a deuterated internal standard.

A gas chromatographic-mass spectrometric method is described for the determination of plasma selegiline. Tetradeuteroselegiline was synthesized and served as the internal standard. Human plasma samples (1 ml) containing 1-6 ng of selegiline were acidified, washed with diethyl ether-hexane, then alkalinized and extracted with heptane-isoamyl alcohol. Analytical separations were performed on a dimethylsilicone capillary column. Detection was by selected ion monitoring of the electron impact generated m/z 96 and 100 alpha-cleavage fragments of drug and internal standard, respectively.

Serum and intestinal diamine oxidase activity during intestinal adaptation.

Diamine oxidase (DAO) is a cytoplasmic enzyme found primarily in the villus epithelial cells of the small intestine. Serum DAO levels have been evaluated as a potential marker of intestinal disease in a variety of disorders, including gut atrophy, ischemia, and inflammation. In this study serum and tissue DAO levels were evaluated during intestinal adaptation. Twenty dogs were divided into 4 groups: sham laparotomy (n = 5), and 25% (n = 5), 50% (n = 5), and 75% (n = 5) distal enterectomy. Serum DAO activity (basal or postheparin) was measured prior to and 2 days, 4 weeks, 8 weeks, and 12 weeks after operation. Tissue DAO and changes in intestinal length, mucosal protein content, and villus height were measured at sacrifice 12 weeks later. Intestinal remnant length and protein content increased significantly with 50 and 75% resection. Tissue DAO activity was significantly decreased with any enterectomy. Serum postheparin DAO activity was significantly greater than basal at all time points but there was no significant change in either basal or postheparin DAO levels at any time following resection. It is concluded that serum DAO levels are not changed during the early adaptive period following intestinal resection and thus would not be useful as a marker of this process. Tissue DAO levels were diminished during adaptation, suggesting that tissue DAO activity is influenced not only by mucosal mass but by cellular metabolism and the proliferative status of the mucosa.

Effect of the progestagen R5020 (promegestone) and of progesterone on the uptake and on the transformation of estrone sulfate in the MCF-7 and T-47d human mammary cancer cells: correlation with progesterone receptor levels.

In the present study we have explored the actions of the progestagen R5020 (Promegestone: 17 alpha, 21-dimethyl-19-nor-pregna-4, 9-diene-3,20-dione) and progesterone on the uptake of [3H]estrone sulfate ([3H]E1S) and its conversion to estradiol (E2) by two hormone-dependent mammary cancer cell lines: MCF-7 and T-47D. R5020 or progesterone significantly decreased the uptake of [3H]E1 and its conversion to (E2). In the cells of the two lines, R5020 or progesterone (5 x 10(-6) M) decreased the E2 concentrations by 2-3 times in relation to the levels in untreated cells. E1S (1 x 10(-7) M) also increased expression of the progesterone receptor (PR) and both R5020 (5 x 10(-6) M) and progesterone (5 x 10(-6) M) blocked this stimulatory action of E1S in cells of both cell lines. As E2 is one of the main factors of cancerization in the breast and estrone sulfate is quantitatively the most important precursor of E2 in this tissue, the decrease of E2 by these progestagens could open new possibilities for the control of E2 in the breast cancer tissue.

Selective versus routine antibiotic use in acute appendicitis.

Whether prophylactic antibiotics should be employed routinely in all patients with presumed appendicitis rather than be administered selectively to those with suspected perforation remains a controversial issue. The outcome of 312 adult patients undergoing appendectomy during periods of selective (I, n = 153) and routine (II, n = 159) antibiotic use were compared. Although the rates of misdiagnosis were comparable (9% vs 13%), significantly more patients with appendicitis in Period II had perforated appendicitis (29 of 139 vs 44 of 139, P less than 0.05). Prophylactic antibiotics were given to 43 (28%) patients in Period I compared to 132 (83%) in Period II (P less than 0.001). This, increased frequency was true for both simple (21% vs 81%, P less than 0.001) and perforated (66% vs 86%, P less than 0.05) appendicitis. A single antibiotic, most frequently a cephalosporin, was used significantly more often in Period II (44% vs 82%, P less than 0.001). There was no significant difference in the methods of wound closure between the two periods. The incidence of infectious complications was similar in patients with simple appendicitis in both periods (8% vs 11%), but it was significantly greater during Period I in patients with perforated appendicitis (45% vs 20%, P less than 0.05). The overall infection rate was similar in both periods (16% vs 22%). Thus, high-risk patients with perforated appendicitis were more likely to receive antibiotics and had a lower infection rate with routine antibiotic use. Furthermore, there was no overall change in the infection rate during this period, despite the use of less toxic, single drug regimens and a greater percentage of perforated appendicitis.