Pulmonary administration of aerosolised fentanyl: pharmacokinetic analysis of systemic delivery

AIMS

Pulmonary drug delivery is a promising noninvasive method of systemic administration. Our aim was to determine whether a novel breath-actuated, microprocessor-controlled metered dose oral inhaler (SmartMist, Aradigm Corporation) could deliver fentanyl in a way suitable for control of severe pain.

METHODS

Aersolised pulmonary fentanyl base 100-300 microg was administered to healthy volunteers using SmartMist and the resultant plasma concentration-time data were compared with those from the same doses administered by intravenous (i.v.) injection in the same subjects.

RESULTS

Plasma concentrations from SmartMist were similar to those from i.v. injection. Time-averaged bioavailability based upon nominal doses averaged approximately 100%, and was > 50% within 5 min of delivery. Fentanyl systemic pharmacokinetics were similar to those previously reported with no trends to dose-dependence from either route. Side-effects (e.g. sedation, lightheadedness) were the same from both routes.

CONCLUSIONS

Fentanyl delivery using SmartMist can provide analgetically relevant plasma drug concentrations. This, combined with its ease of noninvasive use and transportability, suggests a strong potential for field and domicilliary use, and for patient controlled analgesia without the need for i.v. cannulae.

Lack of correlation between the detection of Chlamydia trachomatis DNA in synovial fluid from patients with a range of rheumatic diseases and the presence of an antichlamydial immune response

OBJECTIVE

To resolve how frequently Chlamydia trachomatis and Chlamydia pneumoniae DNA are present in the joints of unselected patients with reactive arthritis (ReA) and undifferentiated oligoarthritis, and to determine if there is an accompanying serologic or cellular antichlamydial immune response.

METHODS

Two polymerase chain reaction (PCR) protocols to detect the plasmid of C. trachomatis and the outer membrane protein 1 gene of C. pneumoniae were developed for specific use with synovial fluid (SF). Subsequently, the assays were used to detect DNA from the 2 organisms in SF from 54 adult patients with rheumatic diseases, including 4 with sexually acquired ReA and 31 with undifferentiated oligoarthritis. The presence of chlamydial antibodies and SF lymphocyte proliferation responses were determined in parallel.

RESULTS

The PCR protocols were species-specific and highly sensitive. SF samples from 15 patients (8 with undifferentiated oligoarthritis, 3 with ReA, 1 with rheumatoid arthritis, and 1 with psoriatic arthritis) were positive for C. trachomatis. There was no significant correlation between the presence of C. trachomatis DNA in the joint and a Chlamydia-specific synovial T cell response or a serologic response. C. pneumoniae was not detected in any of the 54 patients, although it was identified in the SF from a rheumatoid arthritis patient outside this study, demonstrating that the assay was capable of detecting the organism in the joint.

CONCLUSION

C. trachomatis DNA was present in ReA patients and in nearly one-third of unselected patients with undifferentiated oligoarthritis, which further supports the hypothesis that it plays an important role in disease pathogenesis. However, its presence did not correlate with evidence of an antichlamydial immune response. Despite previous anecdotal reports, C. pneumoniae does not appear to be a major cause of undifferentiated oligoarthritis or ReA.

Enhancement of aortic contractility by endothelin following prolonged hypoxia in vivo

The purpose of this study was to determine if endothelin-1 (ET-1) mediates endothelium-dependent enhancement of rat aortic contractility following exposure to hypoxia. Rats breathed room air or 10% oxygen for 12 or 48 h. Thoracic aortas and plasma were analysed for ET-1 content by radioimmunassay. Aortic rings were mounted in organ bath myographs for measurement of isometric tension during activation by phenylephrine (10(-9)-10(-4) M), in the presence and absence of BQ-123. In some rings, the endothelium was removed. Plasma ET-1 levels were 0.79+/-0.09 pg/ml, 2.00+/-0.36 and 1.88+/-0.21 pg/ml, in normoxic rats and rats exposed to hypoxia for 12 or 48 h respectively (P<0.001, 12 or 48 h vs. control). Aortic ET-1 concentrations were 202.3+/-20.8 fg/mg in normoxic rats, compared to 274.9+/-40.6 fg/mg and 292.4+/-24.4 fg/mg in rats exposed to hypoxia for 12 and 48 h, respectively (P<0.01, 12 or 48 h vs. control) and 155.0+/-43.1 fg/mg in de-endothelialized aortas from rats exposed to hypoxia for 48 h (P>0.05 vs. normoxic controls). Maximum tension during phenylephrine-induced contraction was 0.46+/-0.04 mg/g and 0.33+/-0.03 mg/g in endothelialized rings from rats exposed to hypoxia for 48 h in the presence and absence of BQ-123, respectively (P<0.05 for difference), and 0.28+/-0.07 mg/g in rings in which the endothelium had been removed. Local endothelin release is an important mechanism by which the responsiveness of the systemic vasculature to agonists may be preserved during hypoxia.

Chronic Chlamydia pneumoniae infection and asthma exacerbations in children

This study was undertaken to investigate the reported association between Chlamydia pneumoniae and Mycoplasma pneumoniae infection and the expression of asthma-related symptoms. One hundred and eight children with asthma symptoms, aged 9-11 yrs, completed a 13 month longitudinal study. The children maintained a daily diary of respiratory symptoms and peak flow rates. When respiratory symptoms were reported an investigator was called and a nasal aspirate obtained. In total 292 episodes were reported. After the study 65 children provided samples when asymptomatic. The presence of infection was investigated by the polymerase chain reaction for C. pneumoniae and M. pneumoniae and C. pneumoniae secretory immunoglobulin A (IgA) was detected by amplified enzyme immunoassay. C. pneumoniae detections were similar between the symptomatic and asymptomatic episodes (23 versus 28%, respectively). Children who reported multiple episodes also tended to remain PCR positive for C. pneumoniae suggesting chronic infection (p< 0.02). C. pneumoniae-specific secretory-IgA antibodies were more than seven times greater in subjects who reported four or more exacerbations in the study compared to those who reported just one (p<0.02). M. pneumoniae was found in two of 292 reports and in two of 65 asymptomatic samples. In conclusion, chronic Chlamydia pneumoniae infection is common in schoolage children and immune responses to C. pneumoniae are positively associated with frequency of asthma exacerbations. We suggest that the immune response to chronic C. pneumoniae infection may interact with allergic inflammation to increase asthma symptoms. In contrast Mycoplasma pneumoniae was not found to be important in this study.

Characterization of B-cell responses to Chlamydia trachomatis antigens in humans with trachoma

The circulating B-cell responses to Chlamydia trachomatis of 60 children and 34 adults in The Gambia were characterized in a cross-sectional study of different grades of trachoma, using the enzyme-linked immunospot (ELISPOT) assay. Antibody-secreting cells (ASCs) specific to chlamydial major outer membrane protein (MOMP), heat shock protein 60, and whole elementary bodies were detected in children with no evidence of ocular disease, and the immunoglobulin (IgA) response was significantly increased in those with follicular trachoma. In marked contrast, children with the most intense ocular inflammation paradoxically had an almost completely absent B-cell response of all isotypes and to all chlamydial antigens, but with normal serum IgG and IgA responses, which was even lower than in the group with no ocular inflammation. Adults with or without evidence of trachomatous scarring had equivalent numbers of circulating B cells, principally IgA, to all chlamydial antigens. Plasmablasts secreting antibodies to MOMP were present in the urine of children in the absence of urogenital infection detectable by PCR, and relative numbers were 8 to 25 times higher than in blood, suggesting site-specific homing within a common mucosal immune system. These results suggest that ELISPOT assay of ongoing B-cell responses detects suppression of chlamydia-specific IgA ASCs during the proinflammatory response to ocular chlamydial infection seen in intense trachoma, which may play a role in tissue damage leading to trachomatous scarring.

Morphine pharmacokinetics after pulmonary administration from a novel aerosol delivery system

BACKGROUND

Successful pharmacotherapy of pain often depends on the mode of drug delivery. A novel, unit dose, aqueous aerosol delivery system (AERx Pulmonary Drug Delivery System) was used to examine the feasibility of the pulmonary route for the noninvasive systemic administration of morphine.

METHODS

The study had two parts: (1) a dose-ranging study in four subjects with three consecutive aerosolized doses of 2.2, 4.4, and 8.8 mg (nominal) morphine sulfate pentahydrate at 40-minute intervals, and (2) a crossover study, on separate days, in six subjects with 4.4 mg (nominal) aerosolized morphine sulfate administered over 2.1 minutes on three occasions and intravenous infusions of 2 and 4 mg over 3 minutes. Subjects were healthy volunteers from 19 to 34 years old. Arterial blood was sampled for a total of 6 hours and plasma morphine concentrations were measured by gas chromatography-mass spectrometry.

RESULTS

In part 1, plasma morphine concentrations were proportional to dose. In part 2, the mean +/- SD peak plasma concentration (Cmax) occurred at 2.7 +/- 0.8 minutes after the aerosol dose, with mean values for Cmax of 109 +/- 85, 165 +/- 22, and 273 +/- 114 ng/ml for the aerosol and 2 and 4 mg intravenous doses, respectively. The bioavailability [AUC(0-360 min)] of aerosol-delivered morphine was approximately 100% relative to intravenous infusion, with similar intersubject variability in AUC for both routes (coefficient of variation < 30%).

CONCLUSION

The time courses of plasma morphine concentrations after pulmonary delivery by the AERx system and by intravenous infusions were similar. This shows the utility of the pulmonary route in providing a noninvasive method for the rapid and reproducible systemic administration of morphine if an appropriate aerosol drug delivery system is used.

Hyporeactivity of rat diaphragmatic arterioles after exposure to hypoxia in vivo. Role of the endothelium

The effect of prior in vivo hypoxia on the in vitro responses to changes in transmural pressure, alpha-adrenoceptor activation, and depolarization with KCl were evaluated in first-order diaphragmatic arterioles. Rats (n = 14 per group) were exposed to normoxia (controls) or to hypoxia (inspired O2 concentration = 10%) for 12 or 48 h. The arteriolar pressure-diameter relationships were recorded over a pressure range from 10 to 200 mm Hg. In separate groups of arterioles (n = 12 per group), the diaphragmatic arteriolar responses to phenylephrine (10(-8) to 10(-5 M) or KCl (10 to 100 mM) were determined after exposure to either room air or hypoxia for 48 h. In half of the arterioles studied, the endothelium was removed. After 12 h of hypoxia, the pressure-diameter relationship was normal in endothelialized arterioles but was shifted upward in de-endothelialized vessels (p < 0.05). After 48 h of hypoxia, the constrictor response to increasing transmural pressure was severely suppressed in all arterioles. The intraluminal diameters during activation with phenylephrine and KCl were larger in arterioles from rats exposed to hypoxia (103 +/- 8 and 81 +/- 7 microns, respectively) than in control arterioles (41 +/- 5 and 54 +/- 6 microns, respectively; p < 0.05 for differences). During maximum phenylephrine- and KCl-induced constriction in de-endothelialized arterioles, diameters averaged 125 +/- 8 and 105 +/- 8 microns, respectively, for arterioles from hypoxic rats and 32 +/- 6 and 40 +/- 5 microns, respectively, for arterioles from control vessels. Exposure to hypoxia results in impairment of diaphragmatic arteriolar smooth muscle reactivity and reversal of the normal inhibitory influence of the endothelium on diaphragmatic arteriolar tone.

Regulation of cerebellar nitric oxide production in response to prolonged in vivo hypoxia

The aim of this study was to assess the influence of prolonged in vivo hypoxia on cerebellar nitric oxide (NO) production. Conscious rats were exposed to 10% O2 (balanced N2) for 12 or 48 hr (arterial PO2 between 35 and 39 mmHg). The animals were then killed, and the cerebella were quickly frozen. NO production was measured in vitro by monitoring the conversion of L-[3H]arginine to L-[3H]citrulline. Protein and mRNA expressions of the neuronal (nNOS) and endothelial (ecNOS) isoforms of nitric oxide synthases were assessed by using immunoblotting and semiquantitative reverse transcription-polymerase chain reaction, respectively. We also measured mRNA expression of GTP cyclohydrolase I, the rate-limiting enzyme in the synthesis of NOS cofactor, tetrahydrobiopterin, and mRNA and protein expressions of argininosuccinate synthase and argininosuccinate lyase, essential enzymes for the recycling of L-citrulline to L-arginine. Prolonged in vivo hypoxia resulted in a time-dependent increase in cerebellar nitric oxide synthase activity and a significant rise in mRNA and protein expressions of nNOS isoform; however, ecNOS protein expression declined significantly. There was also a rise in mRNA expression of GT cyclohydrolase I; however, neither mRNA nor protein expression of argininosuccinate synthase and argininosuccinate lyase changed significantly in hypoxic animals. These results suggest that prolonged hypoxia increases cerebellar NO formation as a result of upregulation of cerebellar nNOS expression, whereas ecNOS expression declines. We propose that cofactor availability for NO production may also increase during hypoxia because of upregulation of GTP cyclohydrolase I expression. Recycling of L-citrulline to L-arginine, however, remains unchanged.

Echocardiographic detection of pulmonary embolism in transit: implications for institution of thrombolytic therapy

Right atrial or ventricular thrombi in patients with pulmonary embolism are emboli in transit and are a medical emergency because they are associated with a high mortality rate when treated conservatively with anticoagulation. The current standard therapy is less well accepted because of the risk of clot fragmentation and distal embolization. A case in which an unsuspected right ventricular thrombus was diagnosed by echocardiography is reported. This findings led to treatment with streptokinase (250,000 U, followed by 100,000 U/h for 24 h). Clinical improvement was rapidly obtained and the thrombus disappeared 10 h after the initial study. There was no complication. The case illustrates the utility of two-dimensional enchocardiography in the evaluation of patients with pulmonary embolic disease and the efficacy and safety of thrombolytic therapy in the treatment of pulmonary embolism in transit.

Evaluation of intravenous tramadol for use in the prehospital situation by ambulance paramedics

INTRODUCTION

An evaluation of the opioid analgesic tramadol (Zydol, Searle United Kingdom) was carried-out by ambulance paramedics to assess its efficacy in providing pain relief in the prehospital situation.

METHOD

Type of subjects--Patients suffering severe pain from any cause uncontrolled by other simple methods. Number of subjects--101 patients received tramadol and 41 patients served as a control. Study design--Random, open study. Statistical tests--Pain score at scene and on arrival at hospital were compared using Fisher's exact tests (2 sides). Logistic regression analyses also were applied to other factors.

RESULTS

Pain scores improved for 93.1% of the tramadol treated patients and for 44.0% of the controls. A total of 30.7% of patients treated with tramadol complained of nausea after treatment compared with 17.1% before treatment and with 12.2% of the control patients.

CONCLUSIONS

Pain was significantly decreased by the administration of tramadol. It was safe with only minimal side effects, the major one being nausea. Suggestions are made for areas of further study.

Modulation of myogenic responsiveness by CO2 in rat diaphragmatic arterioles: role of the endothelium

The effect of hypercapnia on the myogenic response was determined in arterioles (80- to 100-microm internal diameter) isolated from the diaphragms of rats killed by decapitation. All arterioles were exposed to step changes in intraluminal pressure over a range of 10-200 mmHg and had no flow through their lumen. In five separate groups of vessels (n = 7 per group), PCO2 of the superfusing buffer was adjusted to 40, 60, 80, 90, or 100 mmHg. In three further groups of vessels (n = 7 per group), the endothelium was removed by low-pressure air perfusion (2 ml at 20 mmHg) and PCO2 of the superfusing buffer was adjusted to 40, 80, or 100 mmHg. In endothelium-intact vessels, increasing PCO2 to 80 mmHg enhanced the myogenic response, as reflected by a negative slope of the pressure-diameter relationship (slope = -0.164 +/- 0.03 vs. 0.004 +/- 0.02 for vessels at PCO2 = 40 mmHg, P < 0.05). With a PCO2 of 100 mmHg, dilation accompanied increasing intraluminal pressure and the slope of the pressure-diameter curve was positive (0.154 +/- 0.03, P < 0.05 for difference from vessels at PCO2 = 40 mmHg). In deendothelialized vessels, the curve was shifted upward in a parallel manner during exposure to increased PCO2 levels. Moderate hypercapnia (PCO2 < 80 mmHg) elicits endothelium-dependent enhancement of myogenic tone. Severe hypercapnia (PCO2 > 80 mmHg) inhibits myogenic tone through a direct effect on vascular smooth muscle and through endothelium-dependent inhibitory mechanisms.

Diethyl ether, a chemical asphyxiant used as a prelude to homicide: a report of three cases

Homicides in which the victims are first subdued with a chemical asphyxiant rare unusual and quite rare. We report three cases in which victims were first overcome by ether containing compounds and then killed by other means of asphyxiation. The ether containing compounds used in these three cases were readily available commercial products. In two cases, the distinctive spectra of the volatile compounds in the decedents' blood, from the gas chromatograph and from the gas chromatograph/mass spectrometer, were compared with suspect ether containing products recovered during the scene investigations. In one case, an identical match was obtained. In the other case, the chromatographic spectra differed slightly from the compounds found at the scene, but the difference was explainable by metabolic breakdown of the compounds in vivo.

Intrapleural placement of a nasogastric tube: an unusual complication of nasotracheal intubation

PURPOSE

Although rare, the misplacement of nasogastric tubes into the pleural space has been described. The prognosis of such injuries is improved by prompt recognition; therefore, it is important for physicians who practice nasogastric intubation to be aware of this potential complication, and to be familiar with an approach to early diagnosis.

CLINICAL FEATURES

We present a case of perforation of the cervical oesophagus by a polyvinylchloride nasogastric tube, following a traumatic attempt at nasotracheal intubation. This resulted in passage of the nasogastric tube into the pleural space.

CONCLUSIONS

Our experience with this case and a review of the relevant literature suggest that such trauma may predispose to malplacement of nasogastric tubes. Clinical signs, such as aspiration of fluid from a nasogastric tube, and auscultation of air insufflated into the stomach, are unreliable; however, the presence of subcutaneous air in the neck on chest radiograph, and the presence of cervical crepitance on physical examination, are valuable signs in the early diagnosis of perforation of the cervical oesophagus. Contrast oesophagography remains the diagnostic manoeuvre of choice in confirming the diagnosis, but early diagnosis will depend on a high index of suspicion and prompt viewing of chest x-rays. The management and the prognosis of such injuries depends on the level of the perforation, delays in diagnosis, and the presence of associated mediastinitis.

Estimation of capitation expense for specialty services

Sources of financial uncertainty under capitation plans include not knowing the game rules, using the wrong game rules, basing financial decisions on incomplete data, or even being clueless about the factors that will determine financial risk. Financial risks under managed care can involve price, utilization, selection, and partner risks. Risks can vary by contract type. Controlling risk requires adequate information. Methods to manage risk include the modeling of risk implications; reliance on the law of large numbers; and the use of risk-sharing arrangements, stop-loss insurance, traditional insurance techniques, and various specific contracting techniques.

Effect of acute respiratory acidosis on the limits of oxygen extraction during hemorrhage

BACKGROUND

Hypercapnia can impair cells' capacity to maintain energy status anerobically and enhances the risk of hypoxic injury when oxygen availability is reduced. The ability to maintain tissue oxygenation is determined by both bulk blood flow and the efficiency of oxygen extraction. Bulk blood flow is maintained during hypercapnia through increased sympathetic activity. The effect of hypercapnia on oxygen extraction, however, is unknown. This study evaluates the effect of hypercapnia on cells' capacity to adapt to reductions in oxygen availability by increasing oxygen extraction.

METHODS

In three groups of paralyzed, mechanically ventilated dogs that were anesthetized with alpha-chloralose, the concentration of carbon dioxide in the inhaled gas mixture was adjusted to achieve normocapnia, moderate hypercapnia (Paco2 = 72 +/- 3 [SE] mmHg) or severe hypercapnia (Paco2 = 118 +/- 4 [SE] mmHg). Stepwise hemorrhage was induced until each dog's blood pressure was destabilized. At each stage in the hemorrhage protocol, the oxygen delivery, oxygen consumption, and oxygen extraction ratios (ratio of arteriovenous oxygen content difference to arterial oxygen content) were determined.

RESULTS

At the point of onset of delivery dependence of oxygen consumption, the oxygen delivery rate (critical oxygen delivery) was 7.8 +/- 1.5 (SE) ml.kg-1.min-1 and the oxygen extraction ratio (critical oxygen extraction ratio) was 0.72 +/- 0.04 (SE) in the normocapnic dogs. Moderate hypercapnia had no effect on these parameters. In the severely hypercapnic dogs, the critical values for oxygen delivery and extraction ratios were 12.5 +/- 1.8 (SE) ml.kg-1.min-1 and 0.54 +/- 0.035 (SE), respectively (P < 0.05 for differences from the normocapnic dogs).

CONCLUSIONS

The results identify a previously unrecognized threat to tissue oxygenation and emphasize the importance of ensuring adequate oxygen delivery when adopting mechanical ventilatory strategies that permit respiratory acidosis to develop.

Effect of inhibition of nitric oxide synthesis on the diaphragmatic microvascular response to hypoxia

The purpose of this study was to determine the effect of inhibition of nitric oxide (NO) release on the diaphragmatic microvascular responses to hypoxia. In alpha-chloralose-anesthetized mongrel dogs, the microcirculation of the vascularly isolated ex vivo left hemidiaphragm was studied by intravital microscopy. The diaphragm was pump perfused with blood diverted from the femoral artery through a series of membrane oxygenators. The responses to supramaximal concentrations of sodium nitroprusside, moderate hypoxia (phrenic venous PO2 27 Torr), and severe hypoxia (phrenic venous PO2 15 Torr) were recorded before and after an infusion of NG-nitro-L-arginine (L-NNA; 6 x 10(-4) M) into the phrenic circulation for 20 min. Under control conditions, diaphragmatic blood flow was 12.4 +/- 1.1 ml.min-1.100g-1. Diaphragmatic blood flows recorded during moderate and severe hypoxia were 15.6 +/- 1.2 and 24.3 +/- 1.5 ml.min-1. 100 g-1, respectively (P < 0.05 for both compared with control values). Treatment with L-NNA reduced diaphragmatic blood flow to 9.6 +/- 0.8 ml.min-1.100 g-1 under control conditions (P < 0.05) and caused arteriolar vasoconstriction to a degree that was dependent on vessel size (i.e., larger vessels constricted more than smaller vessels). L-NNA eliminated the increase in blood flow during moderate hypoxia and inhibited arteriolar dilation by an amount that was related to vessel size (i.e., dilation of larger vessels was inhibited more than that of smaller vessels). Inhibition of NO synthesis had no effect on the increase in diaphragmatic blood flow (23.6 +/- 1.9 ml.min-1.100 g-1; P > 0.05 compared with that during severe hypoxia before treatment with L-NNA) or arteriolar diameters during severe hypoxia. NO release plays a role in the diaphragmatic vascular response to hypoxia, but this role is limited to dilation of larger arterioles during hypoxia of moderate severity.

The relationship between upper respiratory infections and hospital admissions for asthma: a time-trend analysis

We have shown that viruses are associated with 80 to 85% of asthma exacerbations in school-age children in the community. We hypothesize that viral infections are also associated with severe attacks of asthma precipitating hospital admissions. To investigate this, we conducted a time-trend analysis, comparing the seasonal patterns of respiratory infections and hospital admissions for asthma in adults and children. During a 1-yr study in the Southampton area of the United Kingdom, 108 school-age children monitored upper and lower respiratory symptoms and took peak expiratory flow rate (PEFR) recordings. From children reporting a symptomatic episode or a decrease in PEFR, samples were taken for detection of viruses and atypical bacteria. A total of 232 respiratory viruses and four atypical bacteria were detected. The half-monthly rates of upper respiratory infection were compared with the half-monthly rates for hospital admissions for asthma (International Classification of Diseases [ICD] code 493) for the same time period for the hospitals serving the areas from which the cohort of schoolchildren was drawn. The relationships of upper respiratory infections and hospital admissions for asthma with school attendance were studied. Strong correlations were found between the seasonal patterns of upper respiratory infections and hospital admissions for asthma (r = 0.72; p < 0.0001). This relationship was stronger for pediatric (r = 0.68; p < 0.0001) than for adult admissions (r = 0.53; p < 0.01). Upper respiratory infections and admissions for asthma were more frequent during periods of school attendance (87% of pediatric and 84% of total admissions), than during school holiday periods (p < 0.001). These relationships remained significant when allowance was made for linear trend and seasonal variation using multiple regression analysis (p < 0.01). Not surprisingly, school attendance, because it is a major factor in respiratory virus transmission, was found to be a major confounding variable in children. This study demonstrates that upper respiratory viral infections are strongly associated in time with hospital admissions for asthma in children and adults. Rhinoviruses were the major pathogen implicated, and the majority of viral infections and asthma admissions occurred during school attendance.

The association of Chlamydia trachomatis/gonococcal infection and tubal factor infertility

OBJECTIVE

To determine the association of past Chlamydia trachomatis and past Neisseria gonorrhoeae infection with tubal factor infertility.

METHODS

A cross-sectional study was conducted. Cases consisted of 55 primary infertile women with laparoscopy confirmed tubal damage (group A) and their husbands, consecutively attending the Infertility Unit at Maharaj Nakorn Chiang Mai Hospital between 1990 and 1992; and 58 primary infertile women with laparoscopy confirmed normal tubes (group B) and their husbands, consecutively attending the same hospital over the same period. Controls consisted of 59 postpartum women (group C) and their husbands omitted to the same hospital over the same period as cases. Past chlamydial and gonococcal infections were assessed by measuring serum IgG antibodies by enzyme immunoassay (EIA). The EIA antigens consisted of purified elementary bodies of C. trachomatis serovar L1, or purified alpha pili of N. gonorrhoeae strain P9.

RESULTS

The prevalence of positive IgG antibody to gonococcal pili in sera from group A was 29.1%, significantly higher than the prevalence of 5.2% in group B or 3.4% in group C (p = 0.000). The husbands of women in group A had a significantly higher prevalence of IgG antibody to gonococcal pili (36.4%) than the husbands of women in group B (8.6%) or group C (18.6%) (p = 0.002). There was no significant difference in positive IgA antibody between case and control groups. After controlling for age, group A showed significantly higher prevalences of past gonorrhea (OR = 32.4, 95% CI 4.3, 242.2) and past chlamydial infection (OR = 3.2, 95% CI 1.2, 8.5) than group C. The husbands of women in group A also had higher prevalences of both types of infection than the husbands of women in group C; the odds ratios for past gonorrhea or chlamydial infections were 2.8 (95% CI 1.1, 6.9) and 2.9 (95% CI 1.2, 7.1), respectively. Neither infertile women with normal tubes (group B) nor their husbands showed any difference when compared with controls.

CONCLUSION

These results suggest that in this region of northern Thailand there is an association between past gonorrhea and past chlamydial infection and tubal factor infertility.

Effect of alpha-adrenoreceptor stimulation on the diaphragmatic oxygen delivery-consumption relationship

PURPOSE

In the vascularly isolated canine hemidiaphragm, we tested the hypothesis that alpha-adrenoreceptor stimulation may influence diaphragmatic function and O2 extraction during reductions in O2 delivery (QO2di).

METHODS

The diaphragm was perfused using a constant flow pump with blood diverted from the left femoral artery. QO2di was reduced in a stepwise fashion by progressive reductions in pump flow. The tension generated by the contracting diaphragm (3 Hz), the critical O2 delivery (QO2di,c) below which O2 consumption (VO2di) becomes dependent on O2 supply and the oxygen extraction ratio at this critical point (ERc) were assessed in two groups of animals. Phenylephrine (10(-5) mol/L) was infused into the phrenic artery in one group and saline was infused in another group.

RESULTS

In the contracting diaphragm, VO2di was higher in the phenylephrine infused group than in the control group (5.2 +/- 0.5 vs 2.11 +/- 0.3 mL/min/100 g). QO2di,c and ERc were also higher in the phenylephrine group than in the control group (6.16 +/- 0.43 vs 3.1 +/- 0.5 mL/min/100 g and 0.87 +/- 0.035 vs 0.63 +/- 0.05, respectively). In the resting diaphragm, VO2di was not significantly different between the two groups and no critical oxygen delivery could be identified in either group.

CONCLUSIONS

These results indicate that alpha-adrenoreceptor activation may increase the tension generated by the diaphragm as well as its oxygen consumption and oxygen extraction. Although this may be beneficial during moderate reductions in oxygen delivery, in more severe shock states, activation of these receptors by endogenous or exogenously administered catecholamines may hasten the development of delivery limitation of VO2di and compromise the ability to sustain ventilation.

Interaction between hypoxia and hypercapnia in regulating canine diaphragm arteriolar diameter

In alpha-chloralose-anesthetized mongrel dogs, the microvascular responses to hypoxia and hypercapnia were studied in the vascularly isolated ex vivo left hemidiaphragm. The diaphragm was perfused with arterial blood diverted from the femoral artery by a pump. A series of membrane oxygenators was used to adjust the blood gas composition of the blood perfusing the diaphragm. Arteriolar diameters were measured by intravital microscopy during an infusion of sodium nitroprusside, moderate hypoxia (phrenic venous PO2 25 Torr), severe hypoxia (phrenic venous PO2 13 Torr), hypercapnia (phrenic venous PCO2 100 Torr), and a simultaneous presentation of hypoxia and hypercapnia. Recordings were made after 15 min under each condition when a steady state had been established for vessel diameter and flow. Pump speed was adjusted manually under each condition to ensure that the steady-state perfusion pressure was the same as that under the control condition. Moderate hypoxia generally resulted in dilation; however, vasoconstriction was seen in some arterioles. Severe hypoxia caused vasodilation that was inversely related to baseline vessel diameter and paralleled the response to sodium nitroprusside. Hypercapnia resulted in vasodilation of the diaphragmatic circulation at values of phrenic venous PCO2 > 80 Torr. The arteriolar response to hypercapnia was also inversely related to baseline vessel diameter. Hypoxia and hypercapnia in combination exerted an additive effect on arteriolar diameter but produced a greater than additive effect on blood flow. Both PO2 and PCO2 may contribute to the local regulation of diaphragmatic blood flow. The vasodilator effects of both hypoxia and hypercapnia are greater in smaller than in larger arterioles. The interaction between PO2 and PCO2 on arteriolar diameter is additive. An apparent synergistic effect on blood flow results from the power function relating diameter to flow.

[Species-specific monoclonal antibodies against the major outer membrane protein (MOMP) of Chlamydia trachomatis]

The synthesized one quarter N-terminal MOMP of C. trachomatis was used for primary immunization of three male BALB/c mice (8 weeks of age), and the boost with C. trachomatis L1/440/Bu elementary bodies (EBs) was followed on day 14. Spleen cells from one mouse with good response of immunization were fused with murine myeloma NS-1 cells on day 24. The hybrid cell suspension was seeded into the wells of 96-well microtest plates which contained macrophage feeder layers. Anti-chlamydial antibodies in culture fluids were screened by ELISA with 1/4 MOMP & L1 EBs coated 96-well trays. Positive wells were cloned by limiting dilution. Four clones which secreted immunoglobulin G1 & G2a class were obtained after elimination of those clones that produced antibodies to C. psittaci strain EAE, C. pneumoniae strain ATCC VR1310 and uninfected BGMK cells. In micro-IF test, we found that the all four clones of MAbs reacted with our laboratory prepared L1, L2, A, B, C, E EBs, L2 tissue culture inclusions, as well as the EBs of all 15 standard serovars of C. trachomatis. The titers of their ascites were more than 1:12,800 in micro-IF test. It was shown that the four clones of MAbs reacted predominantly with 40,000 MOMP of C. trachomatis L1 in Western blot.

SCOTI--a new device for identification of tracheal intubation

A new lightweight device for the detection of placement of a tracheal tube in the trachea or oesophagus is described. The device utilises a sonic technique detecting resonating frequencies in an open (trachea) or closed (oesophagus) structure. Evaluation of the device in a clinical environment is described and it has been shown to be capable of verifying the correct placement of the tracheal tube in the trachea in 98% of patients studied. Further evaluation of this intubating aid appears justified.