Use of proton nmr spectroscopy to measure propofol metabolites in the urine of the female Caucasian patient

1. Six female Caucasian patients received i.v. doses of propofol (2.7 +/- 0.3 (SE) mg/kg) for induction of anaesthesia. Anaesthesia was maintained with nitrous oxide, oxygen and enflurane for periods up to 3 h. A total urine collection was made from each subject for 24 h after administration of propofol; samples were concentrated and analysed for propofol metabolites by nmr spectroscopy. 2. By 24 h, 50.9 +/- 4.0% of the dose of propofol was recovered as metabolites. The proportions of propofol metabolites, 1-quinol glucuronide (1-QG), 4-quinol glucuronide (4-QG), propofol glucuronide (PG) and 4-quinol sulphate (4-QS) recovered in urine (0-24 h) of the patients were 12 +/- 1, 8 +/- 2, 76 +/- 4 and 4 +/- 1% respectively. However, one patient showed a metabolite profile in which PG comprised 93% and 1-QG 7% of the total metabolites. 3. Nmr spectroscopy has been shown to be a satisfactory method for the quantification of propofol metabolites in urine without the necessity for reference samples.

Primary carcinoma of the gallbladder: atypical presentation with gangrenous cholecystitis

Primary carcinoma of the gallbladder developing in patients with longstanding ulcerative colitis is a rare but recognized complication. The authors describe a 45-year-old patient who presented with gangrenous cholecystitis, which was detected by ultrasonography.

Health care and privacy law in electronic commerce

As electronic data interchange (EDI) continues to gain acceptance and use, questions regarding protection of the confidentiality of private healthcare information have arisen. This article explains how a computer-based information system equipped with appropriate safeguards can be far better at ensuring privacy than a paper-based system.

A cross-sectional comparison of persons with syncytium- and non-syncytium-inducing human immunodeficiency virus

The association between isolation of the syncytium-inducing (SI) phenotype of human immunodeficiency virus (HIV) and unfavorable clinical and immune status was evaluated in a cross-sectional study. Data on HIV phenotype were available for 341 of 878 persons entering clinical trials of antiretroviral therapies. Patients with SI virus were demographically similar to those with non-SI (NSI) virus but were more likely to have a diagnosis of AIDS and detectable circulating HIV p24 antigen. Patients with SI virus also had a lower CD4+ cell count and a higher serum level of beta 2-microglobulin. The association between phenotype and present status was explained statistically by CD4+ cell count. Phenotype, serum level of beta 2-microglobulin, and the presence of detectable p24 antigen were all independent predictors of present CD4+ cell count. The likelihood of finding SI virus increased with unfavorable virologic and immunologic parameters and varied with the amount of prior antiretroviral therapy.

Effects of acetaminophen on adverse effects of influenza vaccination in health care workers

OBJECTIVE

To evaluate the effects of acetaminophen on the incidence of adverse effects to, and the immunogenicity of, whole-virus influenza vaccine in health care workers.

DESIGN

Prospective, randomized, double-blind placebo-controlled trial.

SETTING

Health Sciences Centre, an acute care teaching hospital in Winnipeg.

PARTICIPANTS

Of 474 hospital personnel who agreed to undergo influenza vaccination during the 1990-91 season 262 volunteered to participate in the study.

INTERVENTIONS

A dose of 0.5 mL of inactivated trivalent whole-virus influenza vaccine was injected into the deltoid muscle. Volunteers were randomly assigned to ingest two capsules of acetaminophen in a half dose (162.5 mg per capsule) or a full dose (325 mg per capsule) or two identical placebo capsules. Capsules were to be taken at vaccination and at 4, 8 and 12 hours afterward. Subjects were asked to answer questions regarding six symptoms in a diary for the 3 days after vaccination and to record their ingestion of the study medication.

MAIN OUTCOME MEASURES

Incidence of local (sore arm) and systemic (headache, fever, muscle ache, nausea and diarrhea) side effects as well as serum titres of hemagglutination inhibition (HAI) antibody to vaccine antigens before vaccination and 2 weeks and 6 months afterward.

RESULTS

A total of 87, 87 and 88 subjects received the half dose, full dose and placebo respectively; 96% returned the diaries, 83% ingested all four doses of medication, and 87% volunteered all blood samples. Compared with the placebo group the incidence of sore arm was 25% to 28% lower in the half-dose and full-dose groups respectively at 24 hours after vaccination, and the rate of nausea was 90% lower in the full-dose group. The HAI titres were similar among the groups at the three test times.

CONCLUSIONS

The full dose of acetaminophen significantly reduced the incidence of sore arm and nausea without affecting the antibody response. Acetaminophen use may increase the acceptance of influenza vaccine by health care workers in whom concern about side effects is an impediment to vaccination.

Effect of dehydroepiandrosterone on neurotransmitter levels and appetite regulation of the obese Zucker rat. The Obesity Research Program

The obese Zucker rat is a model of youth-onset obesity associated with hyperphagia. In this study, dehydroepiandrosterone's effect at decreasing food intake and body weight in the obese Zucker rat was investigated. Rats were treated with a dehydroepiandrosterone-supplemented diet (0.0, 0.06, 0.15, 0.3, or 0.6%) for 7 days. The 0.3 and 0.6% treatment groups showed a dramatic decrease in daily food intake, which was evident the 1st day. In addition to the reduction in food intake, body weight changes also were affected significantly in the high-dose treatment groups. The possibility that these dehydroepiandrosterone-induced changes were correlated to perturbations in central neurotransmitter levels associated with appetite control was investigated. The hypothalamus, frontal cortex, striatum, and hippocampus of dehydroepiandrosterone-treated animals were assayed for neurotransmitters known to have inhibitory or stimulatory effects on feeding behavior (serotonin, dopamine, norepinephrine, and epinephrine). Significant differences from steroid-free controls were noted only in the levels of hypothalamic serotonin in animals treated with dehydroepiandrosterone. Serotonin in the hypothalamus has been shown to decrease feeding behavior. The magnitude of dehydroepiandrosterone's effect on hypothalamic serotonin correlated with its effect on feeding behavior. Thus, dehydroepiandrosterone may reduce hyperphagia by altering hypothalamic levels of serotonin.

An anatomic and CT scan study of the lateral wall of the sphenoid sinus as related to the transnasal transethmoid endoscopic approach

Interest in endoscopic sinus surgery has expanded to include the sphenoid sinus. While the transnasal transethmoid approach is an established route to the sphenoid sinus, instrumentation is brought close to the lateral wall. This study organizes the lateral wall of the sphenoid sinus into three distinct areas. Fifteen fixed cadaver specimens, 15 fresh specimens and 25 axial as well as coronal CT scans are used to examine each area of the lateral wall. The orbital apex, spongy vascular tissue of the cavernous sinus and the internal carotid artery are found in tandem sequence adjacent to the lateral wall of the sphenoid sinus. A highly pneumatized sphenoid sinus may attenuate the bone over the lateral wall placing the optic nerve and carotid artery at greater risk. Anatomic variations, as examined in this study, and limitations imposed by endoscopic vision via the transnasal transethmoid approach dictates a need to understand the anatomy as well as familiarity with endoscopic surgery. Axial CT scans of the sphenoid sinus can image anatomic variations which may compromise safety of the lateral sphenoid sinus wall.

Effects of sedation and supplemental oxygen during upper alimentary tract endoscopy

The effects of supplemental oxygen therapy on arterial oxygen saturation (SaO2) in unsedated and sedated patients have been studied using pulse oximetry. Hypoxia (minimum SaO2 92% or less) occurred in 41% of unsedated patients breathing room air but in only 11% (p < 0.01) of those receiving supplemental oxygen (41/min) by nasal cannulae. Comparable effects were seen in sedated patients (60% versus 16%, respectively, p < 0.01). Hypoxia during upper alimentary tract endoscopy is common with or without sedation and can be reduced by supplemental oxygen.

Case-control study of factors associated with failure to detect breast cancer by mammography

BACKGROUND

Although mammography is widely used to detect breast cancer, it is recognized that not all cancers can be seen on mammographic images.

PURPOSE

Our purpose was to examine factors associated with failure to detect breast cancer by mammography.

METHODS

A case-control study was carried out in which subjects in whom histologically verified breast cancer was not detected by mammography (false negatives) were contrasted with subjects in whom breast cancer had been detected by mammography (true positives). Mammograms from individuals with histologically confirmed breast cancer were classified independently by two radiologists who were unaware of the clinical or other characteristics of the subjects. Histologic slides of all tumors were reviewed by one pathologist.

RESULTS

Three variables were found to be independently and significantly associated with failure to detect breast cancer by mammography. Breast cancer was less likely to be detected by mammography in the presence of extensive parenchymal densities (odds ratio [OR] = 9; 95% confidence interval [CI] = 1.8-44.3), a tumor of lobular histology (OR = 7; 95% CI = 2.2-22.1), and tumors of small size (OR = 0.10; 95% CI = 0.0-0.9).

CONCLUSION

Our results indicate that biologic factors are associated with failure to detect some breast cancers by mammography and indicate directions for future research in breast imaging.

Relationship between hypoxaemic and cardiac ischaemic events in the perioperative period

We have used continuous and concurrent monitoring of arterial oxygen saturation (SpO2) and ECG to study the relationship between hypoxaemia and silent myocardial ischaemia in the perioperative period in 11 patients with cardiovascular disease. Ischaemic and hypoxaemic events occurred in all patients. Many events were shortlived and occurred independently of each other. However, our results suggest a close correlation between the duration of hypoxaemia and myocardial ischaemia. Ischaemia is more likely to occur if an episode of hypoxaemia is prolonged (beyond 5 min; P less than 0.01, chi square) and severe (SpO2 less than 85%; P less than 0.05, chi square).

Amplification of serotonin-induced arterial contractions with thrombin

The purpose of this study was to determine if exposure of arteries to thrombin increases arterial sensitivity to serotonin and could thereby promote vasospasm. Rings of rabbit abdominal aorta, with endothelium intact or removed, were pretreated with vehicle or thrombin (2.5 U/mL). Thereafter, arterial contractions in response to cumulative additions of serotonin were recorded. Arterial contractions were expressed as a percentage of maximal potassium chloride-induced contractions. Arterial sensitivity was expressed as the EC50, the concentration of serotonin that produced a half-maximal contraction. Exposure of aortic rings to thrombin alone produced contractions of 11% and 22% for rings with and without endothelium, respectively. Removal of the endothelium had no effect on maximal serotonin-induced contractions (93% with endothelium vs 98% without). In contrast, maximal serotonin-induced contractile force was increased after pretreatment with thrombin (107% vs 121% for rings with and without endothelium, respectively; P less than .01). Arterial sensitivity to serotonin was not affected by the removal of endothelium. However, thrombin pretreatment increased (P less than .01) arterial sensitivity to serotonin 2.6-fold and 4.7-fold for rings with and without endothelium, respectively. The results of this study demonstrate that arterial contractions due to serotonin are amplified by thrombin and suggest that vasospasm may be more likely to occur at sites in arteries where the endothelium is absent and both thrombin and serotonin are present.

Combination therapy with zidovudine and dideoxycytidine in patients with advanced human immunodeficiency virus infection. A phase I/II study

OBJECTIVE

To evaluate the safety and immunologic and antiviral effects of combination therapy with zidovudine and dideoxycytidine (ddC) in patients with advanced human immunodeficiency virus type 1 (HIV) infection.

DESIGN

A phase I/II open-label, dose-ranging study.

SETTING

Two AIDS Clinical Trials Group units.

PATIENTS

Patients (56) with advanced HIV disease.

INTERVENTIONS

Patients were randomly assigned to one of three paired regimens of zidovudine and ddC. We evaluated six dosing regimens, each involving oral administration of the study drugs at 8-hour intervals.

MEASUREMENTS

Pharmacokinetics, toxicity, CD4 counts, p24 antigenemia and clinical end points.

MAIN RESULTS

The median follow-up period was 40.6 weeks (range, 0.3 to 70 weeks). Neither drug affected the pharmacokinetic profile of the other. Episodes of serious hematologic toxicity were infrequent, occurring in only 17.9% of patients, and did not differ among the regimens (P = 0.15). Severe sensory peripheral neuropathy occurred in two patients (one patient each in regimens 1 and 4). One patient receiving regimen 4 died. The mean maximal increase in CD4 counts exceeded 109 cells/mm3, and 69% of patients receiving combinations containing 300 or 600 mg of zidovudine daily had an increase in CD4 counts of 50 cells/mm3 or greater. Regimens containing 600 mg of zidovudine daily (regimens 2 and 5) were also more likely to result in persistent increases in CD4 counts above pretreatment values than were the two lowest dose regimens (P = 0.003). The decline in CD4 counts was more rapid, and the suppression of the p24 antigenemia was less rapid and less sustained in patients receiving the lowest zidovudine dose alone (regimen 6). The addition of ddC to regimen 6 (regimen 3) resulted in a slower decline in the CD4 counts (P = 0.06).

CONCLUSIONS

Combination therapy with zidovudine and ddC at the doses tested was well tolerated and did not result in toxicity. A daily oral dose of 150 mg of zidovudine appeared to produce a suboptimal effect on p24 antigenemia and CD4 counts. Combination therapy with ddC and higher doses of zidovudine produced greater and more persistent effects in patients with advanced HIV infection compared with other study regimens and with the results of previous trials of zidovudine monotherapy.