Inhibition of inducible nitric oxide synthase ameliorates endotoxin-induced gut mucosal barrier dysfunction in rats

BACKGROUND & AIMS

The permeability of intestinal epithelial monolayers increases after exposure to nitric oxide. The aim of this study was to investigate the role of excessive NO production on intestinal barrier function in rats injected with lipopolysaccharide (LPS).

METHODS

Rats were injected with saline or LPS (5 mg/ kg). Bacterial translocation to mesenteric lymph nodes, liver, and spleen was assessed 24 hours after LPS injection. Mucosal permeability was determined by loading fluorescein-labeled dextran (mol wt, 4000 daltons) into an intestinal segment and measuring its appearance in plasma. Intestinal mucosal mitochondrial respiration was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

RESULTS

Intestinal tissue from LPS-challenged rats showed upregulation of inducible NO synthase (iNOS) messenger RNA expression and subsequent up-regulation of iNOS enzymatic activity. Plasma concentrations of nitrite plus nitrate (NO2-/NO3-) were increased for at least 24 hours after injection of LPS. Treatment with the selective iNOS inhibitor, aminoguanidine, inhibited iNOS enzymatic activity and overproduction of NO2-/NO3-. LPS-induced bacterial translocation was reduced by aminoguanidine. LPS-induced intestinal hyperpermeability was ameliorated by both aminoguanidine and another selective iNOS inhibitor, S-methylisothiourea. LPS depressed intestinal mucosal mitochondrial function, and this effect was ameliorated by aminoguanidine.

CONCLUSIONS

Overproduction of NO may contribute to intestinal barrier dysfunction in LPS challenged rats, possibly by interfering with mitochondrial oxidative metabolism.

Nutritional supplementation and the development of linear enamel hypoplasias in children from Tezonteopan, Mexico

The purpose of this study was to compare the effect of nutritional intake during tooth-crown formation on the subsequent development of linear enamel hypoplasias (LEHs) in Mexican nonsupplemented (control) adolescents (n = 42) and adolescents who had received daily nutritional supplements since birth (n = 42). The proportion of individuals with LEHs was nearly two-fold greater (74.4%; 95% CI 64.7-84.1%) in the control than in the supplemented group (39.5%; 95% CI 28.6-50.4%; chi 2 = 9.44; P = 0.001). Although the estimated peak age at formation, approximately 2-2.5 y, is similar in both groups, the proportion of early (before 1.5 y) and late (after 3.0 y) LEHs was greater in the control group. LEH was also more common in females and was associated with an increase in illness days and a decrease in growth velocity. Results of this study suggest that mild to moderate undernutrition during enamel formation is causally linked to the formation of LEHs.

Mitochondrial reactive oxygen species generation in obese non-diabetic and type 2 diabetic participants

AIMS/HYPOTHESIS

The aim of this study was to measure mitochondrial reactive oxygen species (ROS) production directly from skeletal muscle biopsies obtained from obese insulin-resistant non-diabetic and type 2 diabetic participants.

METHODS

Ten lean healthy, ten obese non-diabetic and ten type 2 diabetic participants received a euglycaemic-hyperinsulinaemic clamp to measure whole body insulin sensitivity. Mitochondria were isolated from skeletal muscle biopsies, and mitochondrial ATP synthesis and hydrogen peroxide production were measured ex vivo under conditions that maximally stimulate ATP synthesis and ROS production using chemiluminescent and fluorescent techniques, respectively.

RESULTS

Compared with lean controls, both obese non-diabetic and type 2 diabetic participants were resistant to insulin, and had a reduced rate of mitochondrial ATP production. Obese insulin-resistant participants had a decreased rate of mitochondrial ROS production, while ROS production rate in participants with type 2 diabetes was similar to that in lean healthy participants. In non-diabetic participants, the rate of ROS production was strongly correlated with the rate of ATP synthesis and the glucose disposal rate measured with the euglycaemic-hyperinsulinaemic clamp. The ROS/ATP ratio in obese insulin-resistant participants was similar to that in lean insulin-sensitive participants, while the ratio was significantly elevated in type 2 diabetes participants.

CONCLUSIONS/INTERPRETATION

Since, in absolute terms, the maximal capacity for mitochondrial ROS production was not increased in either obese insulin-resistant participants or in type 2 diabetic participants, these results do not favour a role for increased mitochondrial ROS production in the pathogenesis of insulin resistance in human skeletal muscle. However, care should be taken in extrapolating these ex vivo observations to the in vivo situation.

Arterial blood pressure and individual modernization in a Mexican community

The relationship between changes in individual behavior and arterial blood pressure was studied in a town in central Mexico. Two models relating modern behaviors and blood pressure were examined. The first, or 'accretion model' suggests that any adoption of modern behaviors results in stress and deleterious health change. The second, or 'discrepancy model', suggests that the adoption of modern behaviors is problematic only when the individual has limited access to economic resources. Empirical support for both models was found, but the best predictor of blood pressure was a single index of modern lifestyle, including acquisition of material culture and engaging in cosmopolitan behaviors. The effect of modern lifestyle on blood pressure was independent of the effects of age, sex, sodium intake, and body mass index. Overall the results are consistent with a model in which degree of community modernization, especially as it influences social class structure, is a boundary condition determining the relationship between the adoption of modern behaviors and health status.

A Case of COVID-19 Vaccine Associated New Diagnosis Myasthenia Gravis

An 82-year-old man presented with intermittent episodes of slurred speech during his evening meals after receiving the BNT162b2 COVID-19 vaccine. Thorough evaluation was conducted including lab work and EMG confirming a new diagnosis of late-onset myasthenia gravis. Despite treatment, the patient progressed rapidly to severe exacerbation requiring intubation and placement of a PEG tube. Infections provoking new diagnosis and exacerbations of myasthenia gravis have been reported. New diagnosis of myasthenia gravis associated with the COVID-19 vaccine is rarely reported. This case highlights the need for clinicians to be aware of the uncommon presenting symptoms in late-onset myasthenia gravis and the possibility of vaccine provoked diagnoses of immune mediated diseases.

Social support and arterial pressure in a central Mexican community

Research on the relationship of social support and arterial blood pressure was conducted in a town in central Mexico. A culturally appropriate measure of social support was developed assessing perceived support from relatives, friends, neighbors, and compadres (ritual kin). The effects of perceived support from these four sources were compared to the effects of the amount of reported social contacts. For males, more support from all four sources was related to lower arterial pressure, whereas amount of social contact was related to higher diastolic blood pressure; support from compadres had the largest inverse correlation with blood pressure. For females the pattern of correlations was dependent on age: support from relatives and friends was related to higher blood pressure for younger females, whereas support from relatives was related to lower blood pressure for older females. This pattern of relationships is consistent with the place of women in the social structure of this Mexican community, and these results point to the need to conceptualize and measure social support in culturally appropriate ways.

LOCALIZATION OF ANGIOTENSIN II RESPONSES IN THE TROUT CARDIOVASCULAR SYSTEM

The renin/angiotensin system (RAS) is a tonic anti-drop regulator of arterial blood pressure in many teleosts. In trout, angiotensin II (ANG II) has no direct constrictor effect on large arteries or veins and the identity of specific cardiovascular pressor effectors is unknown. Potential targets of angiotensin activation were examined in the present experiments using perfused organs and isolated tissues from the rainbow trout Oncorhynchus mykiss. Perfused gill (arches 2 and 3), perfused skeletal muscle-kidney (via the dorsal aorta; PDA) and perfused splanchnic (via the celiacomesenteric; PCM) circulations vasoconstrict in response to salmonid ANG II in a dose-dependent manner. ANG II was significantly (P¾0.05) more potent in the PCM than in the PDA, and both preparations were more responsive than the gills: pD2=8.0±0.20 (10) for PCM; pD2=7.5±0.07 (13) for PDA; pD2=6.9 ±0.21 (8) for gill arch 3; pD2=6.7±0.23 (8) for gill arch 2; mean ± s.e.m. (N), respectively. Salmonid angiotensin I (ANG I) also produced a dose-dependent constriction of the PDA and PCM. Angiotensin converting enzyme (ACE) activated nearly 100 % of ANG I to ANG II in a single pass through the PDA, whereas PCM conversion was estimated to be less than 10 %. Inhibitors of adrenergic constriction partially prevented ANG II responses in the PDA but did not affect PCM responses. ANG II did not affect paced rings of ventricular muscle in the presence of high or low [Ca2+] or epinephrine concentrations, nor did it have any inotropic or chronotropic effects in the in situ perfused heart. Red blood cell swelling was unaffected by ANG II. Similarly, the effects of ANG II on gut, urinary bladder and gall bladder smooth muscle were negligible or non-existent; thus, an increase in splanchnic resistance due to extravascular compression can be discounted. These results indicate that, in trout, the systemic microcirculation is the major cardiovascular effector of angiotensin-mediated pressor responses. In addition, the RAS has little direct effect on non-vascular smooth muscle or the heart. From an evolutionary perspective, the initial site of direct systemic RAS action appears to be the vascular microcirculation.

Household size, food intake and anthropometric status of school-age children in a highland Mexican area

Large household size is widely regarded as a risk factor for malnutrition in developing countries, particularly for infants and young children. This study examines the extent to which household size is related to nutritional status in school-age children in the Solis Valley in highland Mexico. The relationships of food intake, anthropometric measures, and household size are assessed in a sample of 110 children (7-9 years of age), who were followed longitudinally for a minimum of one year as part of the Collaborative Research Support Program on Food Intake and Human Function. Diets in the valley are characterized by very low intake of animal food products and are heavily dependent on maize, which is primarily home-produced. Growth faltering is pervasive; the mean Z score for height-for-age in the sample is--1.6 of the NCHS reference standard. Children from larger households are significantly shorter and consume diets of poorer quality, as assessed by intake of foods from animal sources. These relationships remain statistically significant in regression analyses that control for household economic status. It therefore appears that the resources available to households in the Solis Valley are inadequate to buffer children in even more advantaged households from the stresses of maintaining large families.

Membranous nephropathy: response to steroids and immunosuppression

In a retrospective study, the clinical course of 23 adult patients with documented idiopathic membranous nephropathy was reviewed. These patients included 16 men and 7 women, who were followed for a period of as long as 9 years, 22 patients (95.7%) were nephrotic (proteinuria of 3 g or more in 24 h) and 6 (26%) were hypertensive. 5 patients were treated with prednisone alone, 12 with prednisone and cyclophosphamide, 2 with prednisone and azathioprine and 4 received no treatment. 18 patients achieved complete remission (78.3%). 16 of these (88.9%) were treated with prednisone, or prednisone and cyclophosphamide or azathioprine, and the remaining remitted spontaneously. In 3 additional patients, proteinuria improved with treatment with prednisone and immunosuppression but remained in the nephrotic range in 2, and fell to 1.8 g/day in 1. Patients who failed to respond to steroids showed remarkable improvement when therapy with cyclophosphamide was added. Of the 4 patients not treated, 2 underwent spontaneous remission and 2 developed renal insufficiency. These results suggest a beneficial effect of steroids in the treatment of membranous nephropathy, and suggests further that cyclophosphamide may be effective in patients not responding to steroids alone. Finally, these results suggest that in many patients therapy may have to be prolonged before a remission can be observed.

A comparison of cycle control with monophasic levonorgestrel/ethinylestradiol 100 micrograms/20 micrograms versus triphasic norethindrone/ethinylestradiol 500-750-1000 micrograms/35 micrograms: a multicenter, randomized, open-label study

OBJECTIVES

This multicenter, randomized, open-label study was undertaken to compare the effects on menstrual cycle control of two oral contraceptive regimens: monophasic levonorgestrel (LNG) 100 micrograms/ethinylestradiol (EE) 20 micrograms (Alesse or Loette) and triphasic norethindrone (NET) 500-750-1000 micrograms/EE 35 micrograms (OrthoNovum 7/7/7).

METHODS

Healthy women with normal menstrual cycles were enrolled and completed up to four cycles of study medication. A total of 384 cycles in the LNG/EE group and 400 cycles in the NET/EE group were evaluable for analysis of cycle control.

RESULTS

For all treatment cycles, the percentage of cycles classified as normal was consistently higher in the LNG/EE group than in the NET/EE group. By cycle 4, 69.9% of cycles with LNG/EE and 54.4% with NET/EE (p < 0.05) were normal. In individual cycles, consistently lower occurrences of intermenstrual bleeding (total bleeding and/or spotting) were seen for the LNG/EE group, although these differences were not statistically significant. Withdrawal bleeding characteristics were comparable between the two groups, except for the length of the latent period, which was significantly longer in the LNG/EE group. The incidence of treatment-emergent adverse events was similar in the two groups.

CONCLUSION

This study indicates that the monophasic LNG/EE 100 micrograms/20 micrograms provides better cycle control than the multiphasic NET/EE product, despite its lower EE dose.

Clinical application of continuous flow apneic ventilation

Continuous flow apneic ventilation (CFAV) was studied in five adult female patients. After induction of anesthesia with thiopental sodium (5 mg/kg) and fentanyl (5 micrograms/kg), and paralysis with pancuronium bromide (0.12 mg/kg), the patients were ventilated with oxygen at an FIO2 of 1.0 by face mask. Two polyethylene catheters (outside diameter [OD] 2.5 mm) were each inserted into the right and left mainstem bronchi. Each catheter had a curved tip measuring 2 cm in length. The angulation of the catheter tip from the axis was 20 degrees for the right side and 30 degrees for the left side. The endobronchial position was checked by fiberoptic bronchoscopy. Subsequently, tracheal intubation was performed using a 7.5 mm OD tracheal tube. CFAV was started when both catheters were connected to the gas delivery system. Humidified oxygen was delivered at total flows between 0.6 and 0.7 1/min. Arterial blood gases were analyzed every 5 min for 30 min. Monitoring included electrocardiogram, indirect blood pressure, heart rate, temperature, and peripheral nerve stimulation. Adequate oxygenation was maintained in all patients, 39.76 +/- 4.32 kPa (299 +/- 37 mmHg) at 30 min. There was a significant rise in Paco2 (P less than 0.05) at 30 min compared to the control, 4.92 +/- 0.25 kPa compared to 7.30 +/- 0.53 kPa (37.0 +/- 1.9 mmHg compared to 54.9 +/- 4.0 mmHg). There was a mean rise in Paco2 of 0.03 kPa/min (0.6 mmHg/min) compared to 0.5 kPa/min (3.8 mmHg/min) with apneic diffusion ventilation. In one patient there was no increase in Paco2 during the 30 min of CFAV.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of the economic impact of an overage reduction program in the operating room

STUDY OBJECTIVES

To delineate excessive supply preparation in the operating rooms (ORs) of Yale-New Haven Hospital, and to measure the reduction in such overage as a result of nursing and administration cost-containment efforts.

DESIGN

Before and after trial.

SETTING

Inpatient ORs of Yale-New Haven Hospital.

INTERVENTIONS

After the initial documentation of overage, several cost-containment measures were instituted, including nursing education, review of overage data, and updating of surgical request lists.

MEASUREMENTS AND MAIN RESULTS

The hospital cost of case-specific overage generated by all surgical procedures performed during two 2.5-month periods in 1992 and 1994 (before and after the interventions) were compared. One-thousand three hundred eighteen cases in 1992 were compared with 1,367 cases in 1994. A 45% reduction in mean per case overage occurred between the two assessment periods. Extrapolation of the data to the incidence of similar cases throughout the United States projected a comparable savings.

CONCLUSIONS

Efforts to increase the efficiency of OR supply management can be measured, in part, by overage evaluation, which can serve as a resource for focusing efforts at cost-containment.

Risk analysis of coronary bypass surgery after acute myocardial infarction

BACKGROUND

Current strategies for management of acute myocardial infarction (MI) include thrombolysis, angioplasty, and coronary bypass surgery singly or in combination. This study was designed to identify contemporary risk factors for coronary bypass surgery among patients in this high-risk group.

METHODS

Between June 1992 and December 1995, 1181 consecutive patients underwent isolated coronary bypass surgery. Of these, 316 underwent coronary bypass surgery within 21 days of MI. Mean age was 65 years (range, 33 to 87 years), and 73% were male. There were 166 patients with stable angina (group 1), 107 patients with unstable angina requiring intravenous nitroglycerin for a control of ischemia (group 2), 20 patients with angina requiring intraaortic balloon counterpulsation for stabilization (group 3), and 23 patients with severe postinfarction ischemia complicated by cardiogenic shock (group 4).

RESULTS

The overall in-hospital mortality rate was 5.1% (16 of 316), which was higher (p < 0.05) than the 2.5% (22 of 865) among patients undergoing coronary bypass surgery without recent myocardial infarction. Mortality increased with severity of clinical preoperative status and was 1.2% in group 1, 3.7% in group 2, 20.0% in group 3, and 26% in group 4. Serious postoperative morbidity occurred in 7.3% of patients. Multivariate logistic regression analysis identified preoperative intraaortic balloon counterpulsation, left ventricular dysfunction, and renal insufficiency as the only independent correlates of mortality.

CONCLUSIONS

Coronary bypass surgery can be safely performed in stable patients at any time after acute MI, with an operative mortality similar to elective surgery. Thus, in this era of medical cost containment, there is no apparent indication for prolonged stabilization attempts that delay surgery.

Molecular epidemiology of human rotaviruses in Santiago, Chile

BACKGROUND

Protective immunity against rotavirus infection is directed against antigenic epitopes on the outer capsid proteins VP7 and VP4. Our aim was to characterize the epidemiology of rotavirus antigenic types over time in Santiago, Chile.

METHODS

We prospectively obtained 2097 stool samples for rotavirus testing, VP7 (G1 to G4) and VP4 (P4, P6, P8, P9) typing from children with diarrhea evaluated in emergency rooms of 5 base hospitals of Santiago. In addition 256 rotavirus-positive samples collected between 1985 and 1987 in the north health care area of Santiago were studied.

RESULTS

Of 995 rotavirus-positive samples obtained 825 (82%) were typable for 1 or more VP7 types. G1 represented 81% of the G-typed samples during 1993 through 1995 and 77% during 1985 through 1987, predominating in all health care areas. G2 was next most common in all 5 areas, representing 6 to 23% of typed samples, with 1 area, the Southeast concentrating a significantly higher number of G2 infections. G2 declined from 35% of rotavirus-positive samples in 1993 to 0% in 1995 (P < 0.001), and from 25% to 2% in the north health care area from 1985 to 1987 (P < 0.001). G4 was uncommon and significantly more prevalent in 1985 through 1987 than in 1993 through 1995 (7% vs. 3%, P = 0.015). G3 was not detected. G1P8 (53%) and G2P4 (16%) combinations were by far the most commonly detected G-P associations.

CONCLUSIONS

In Santiago, Chile, rotavirus antigenic type G1P8 has been highly prevalent and G2P4 has circulated in cycles. Differences in epidemiology of rotavirus antigenic types worldwide may prove to be relevant in efficacy of rotavirus vaccines.

Rabeprazole containing triple therapy to eradicate Helicobacter pylori infection on the Texas-Mexican border

BACKGROUND

Antibiotic resistance and duration of therapy influence the success of proton-pump inhibitor-containing Helicobacter pylori eradication therapy. Clarithromycin resistance is associated with treatment failure.

AIM

To examine the success of a 7-day rabeprazole-clarithromycin-amoxicillin therapy in the study population.

METHODS

Adults from Ciudad Juarez with H. pylori infections identified by culture or histology received rabeprazole 20 mg, clarithromycin 0.5 g and amoxicillin 1 g, each b.d. for 7 days. Outcome was assessed by 13C-urea breath test carried out 4+ weeks after treatment.

RESULTS

A total of 111 patients were enrolled and evaluated by urea breath test; 102 completed the full 7 days therapy. Two deviated from protocol, and five stopped because of adverse events. The cure rate (intention-to-treat) was 85% (95% CI: 78-91%); the per-protocol cure rate was 85% (95% CI: 78-91%). Side-effects were not serious and only 6.6% of those with adverse events stopped medication. Only three isolates were clarithromycin-resistant and none was cured. Compliance explained most of the successes.

CONCLUSIONS

In the study population a 7-day rabeprazole triple eradication therapy was both effective and well-tolerated. Clarithromycin resistance was uncommon. We observed a slightly better outcome but consistent with results from recent large studies in US populations.

A cautionary note on the use of autoregressive models in analysis of longitudinal data

Rosner et al. presented a simple, easily implemented modelling method for retaining time order relationships in analyses of longitudinal data when successive measures are correlated. Evaluation of time order is particularly useful in epidemiologic studies concerned with exposure to potentially toxic substances and subsequent outcome, but may also have use in more traditional growth studies that relate intake to subsequent development. The analysis allows for unequally spaced measures and missing data. The estimation method permits varying numbers of observations per subject and, with measures equally spaced, one can fit the model with use of ordinary least squares regression software. We report on a potential false association that can result when both exposure and outcome are related to time. We illustrate this problem with a small scale simulation and example. We also note a more serious problem with Rosner's approach in interpreting parameters. Although the model may be useful for prediction, parameters depend on the autocorrelation and are not readily interpretable. We recommend alternative modelling strategies be used when autocorrelation of errors is suspected.

Expression of the epidermal growth factor receptor (EGFR) pathway in cervical cancer (CC) patients (pts)

5519

Background: EGFR, a membrane tyrosine kinase receptor that regulates multiple functions such as cell growth, differentiation, gene expression and development through at least 3 pathways, is overexpressed in a wide variety of solid tumors, including CC. The downstream activation of the EGFR pathways has not been studied extensively. The aim of this study is to assess the correlation between EGFR-HER-2-HER-3-HER-4 status, downstream pathways (STAT 3, survivin, RAS) with pt characteristics, overall survival and recurrence free survival in pts diagnosed with invasive CC. Methods: Receptor expressions were assessed by immunohistochemistry on 80 pts from our clinic. Tumors were scored by percentage of cells stained multiplied by intensity for a score range of 0–300 by two pathologists. Median EGFR score was 140. Pts were categorized as low expressor (EGFR score lower than 140) or as high expressor (EGFR score greater than 140). Differences in receptor expression were compared using the Log-rank test for overall (OS) and recurrence-free survivals (RFS) and by Chi-square analyses for the clinical parameters (age, stage, histology, and grade). Results: A total of 80 pts data was analyzed. Mean age of the sample was 48 years. 23% of pts had well differentiated tumors. 80% had squamous histology. 39% had stage IIB or higher. 25% died of cancer. By Log-rank test, standard prognostic factors (age, stage, grade, and histology) showed the expected differences in survival, confirming the validity of the sample. However there were no correlations between the clinical parameters, OS, or RFS with EGFR expression. Data on HER-2–3-4, STAT3, survivin and RAS will be presented at the meeting. Conclusions: Although no correlation has been found between clinical outcome and EGFR expression, EGFR inhibitors of the extracellular domain are expected to be useful for the treatment of CC that overexpress this receptor. These results will serve as baseline data needed to test cetuximab and other EGFR inhibitors in pts with CC.

No significant financial relationships to disclose.

Medicolegal aspects of imaging and Internet communications

Many facial plastic surgeons have set up their own personal World Wide Web (WWW) pages with an electronic mail link to communicate with and educate prospective patients. The possible dilemma is in that these services are provided without actually meeting patients face to face. Also, despite the growing popularity of computer imaging systems, it is not clear whether the medical and legal advantages of using such a system outweigh the disadvantages. The purpose of this article is to evaluate these aspects and to provide some protective guidelines. An examination of possible causes of actions arising from computer imaging suggests that surgeons who follow a few simple guidelines, and who use computer imaging responsibly and cautiously, minimize their legal liability. Issues surrounding Internet discussion groups, posted medical advice, intellectual property, and the use of an electronic mail link are also discussed.