Urinary urea nitrogen: too insensitive for calculating nitrogen balance studies in surgical clinical nutrition

Urinary urea nitrogen (UUN) has been used as an estimate of total urinary nitrogen (TUN) when calculating nitrogen output for nitrogen balance (NB) studies. UUN is assumed to constitute 80 to 90% of the total nitrogen output; when estimating TUN from UUN, UUN values are multiplied by 1.25 to correct for non-urea nitrogen components. In order to evaluate the validity of estimating total urinary nitrogen output from measured UUN in a clinical setting, 491 UUN:TUN paired studies were performed on 24-hour urine collections in general surgical/trauma patients who had measured TUN outputs ranging from 0.04 to 54.0 g/d. Assessment of 315 NB studies was done to compare NB values of those calculated by using UUN as an estimate of TUN with those calculated from measured TUN. Patients in both studies were subdivided into four stress categories, using TUN/day as the index: less than 5 g, 5-10 g, 10-15 g, and greater than 15 g. On average, 80 to 90% of TUN is represented by the UUN. However, in our patient population the variability ranged from 12 to 112%. If these UUN values are used as estimates for TUN in calculating NB, variations of up to 12 g/d would result. Application of the correction factor of 1.25 is not consistent in correcting for nonurea nitrogen components in this clinical setting. The use of actual rather than estimated TUN may be a more accurate and appropriate method than UUN when calculating NB.     

Physiology and metabolism in isolated viral septicemia. Further evidence of an organism-independent, host-dependent response

The hypothesis has been advanced that the human systemic septic response is a function of the host and not of the type of infecting organism. Metabolic and physiologic data from five immunosuppressed transplant recipients with isolated cytomegaloviral sepsis and viremia were prospectively evaluated. Serial cultures obtained from lung, sputum, urine, wound, blood, and invasive lines were positive for virus and negative for bacterial or fungal pathogens. The results were compared with two data banks derived from either victims of multiple trauma without sepsis or surgical patients with early bacterial or fungal sepsis. Statistically significant differences between the patients and the nonseptic reference group were noted for cardiac index, total peripheral resistance, arteriovenous oxygen content difference, oxygen consumption, and levels of triglycerides, proline, phenylalanine, tyrosine, alpha-aminobutyrate, and alanine. No such differences were present for these data compared with the septic reference group. Physiologic data obtained just before death in three patients indicated a failure of oxygen transport. It appears that the systemic septic response to viral agents is indistinguishable by physiologic and metabolic criteria from that resulting from bacterial or fungal agents.     

Molecular characterization of a novel form of (A gamma delta beta)zero thalassemia deletion in a Chinese family

We have identified and molecularly characterized a novel deletion in the beta-globin gene cluster that is associated with elevated fetal hemoglobin in the adult. The propositus is a homozygote from the Yunnan province of China. The deletion spans about 90 kb of DNA and removes the A gamma, delta, and beta-globin genes. The 5' breakpoint of the deletion is located about 0.13 kb upstream from the A gamma-globin gene, whereas the 3' breakpoint is located about 66 kb downstream from the beta-globin gene, about 13 kb upstream from the breakpoint of the Chinese (A gamma delta beta)zero-thalassemia. Heterozygotes for this Yunnanese form of (A gamma delta beta)zero-thalassemia express between 9% and 17% of fetal hemoglobin, whereas the homozygote present with a mild anemia (Hb = 10.7 g/dl). Comparison of the sites of 3' breakpoints of the Yunnanese and the Chinese (A gamma delta beta)zero-thalassemia mutants is compatible with the hypothesis that an enhancer element is located between the 3' breakpoints of these two mutants. Juxta-position to the G gamma gene of this element may be responsible for the efficient gamma-gene expression in the Yunnanese mutant.     

Clinical implications of a patent foramen ovale in patients with massive pulmonary embolism

Summary The aim of our investigations was to prospectively evaluate the clinical relevance of a patent foramen ovale in patients with acute massive pulmonary embolism with regard to mortality, the occurrence of cardiovascular complications and the extent of arterial hypoxemia. In 85 patients and in a second study in 139 patients with acute massive pulmonary embolism a right-to-left shunt was diagnosed by contrast echocardiography. A patent foramen ovale was found in 39% of the patients in the first and in 35% in the second study. With regard to the extent of arterial hypoexemia the oxygen tension was significantly lower in patients with a patent foramen ovale (55±14 mm?Hg?vs 62±16 mm?Hg). Furthermore in the second study, clinical symptoms presumptive of paradoxical embolism occurred in 13 patients (27%) with a patent foramen ovale and in 2 patients (2.2%) without a patent foramen ovale. During the inhospital stay, patients with a patent foramen ovale had a death rate of 33% as opposed to 14% in patients without a patent foramen ovale. Logistic regression analysis demonstrated that after adjustment for the clinical characteristics the only independent predictors of inhospital mortality were arterial hypotension at presentation (p<0.01) and a patent foramen ovale (p<0.001). Patients with a patent foramen ovale also had a significantly higher incidence of cardiovascular complications. Overall, the risk of a complicated in-hospital course was 5.2 times higher in the patient group with a patent foramen ovale. These investigations underlines the prognostic impact of a patent foramen ovale in high-risk patients with acute massive pulmonary embolism.     

Large emboli on their way through the heart - first live demonstration of large paradoxical embolisms through a patent foramen ovale.

We report a case of large paradoxical embolisms through a patent foramen ovale in a patient with acquired heparin-induced thrombocytopenia type II (HIT). One large ventricular thrombus embolizing through the aortic valve was documented on videotape for the first time while performing transesophageal echocardiography. A 56-year-old man was admitted with acute respiratory failure initially believed to have an exacerbated chronic obstructive pulmonary disease. Arterial oxygen saturation was only 33%. He received antibiotic and anti-obstructive treatments and was mechanically ventilated for 7 days. Few hours after extubation, he developed recurrent severe dyspnea accompanied by acute pain and pulselessness in his left leg. Transthoracic echocardiography revealed an enlarged right ventricle and suggested the presence of free-floating thrombi both in the right and in the left-heart cavities. During transesophageal echocardiography, a large serpentine left-heart thrombus embolized through the aortic valve and disappeared. The patient developed ventricular fibrillation and underwent successful cardiopulmonary resuscitation including emergency thrombolysis with alteplase. Four hours later, the surgeon retrieved a 20-cm long thrombus from the left femoral artery.     

Is it time for home treatment of pulmonary embolism?

Acute pulmonary embolism (PE) is a frequent cause of death, but not all patients are at high risk of an adverse early outcome. It has been proposed that selected patients may be considered for early discharge and home treatment, but it was only recently that improved risk assessment strategies permitted advances in the identification of low-risk PE. Clinical prediction rules, such as the Pulmonary Embolism Severity Index (PESI), and laboratory biomarkers, particularly natriuretic peptides and cardiac troponins, appeared capable of excluding severe PE and serious comorbidity. Recently, two randomised trials and two prospective cohort studies investigated the feasibility and safety of outpatient treatment. All excluded patients with haemodynamic instability and serious comorbidity, but only one trial used a validated clinical score (PESI) for patient inclusion, and only one cohort study employed a biomarker test. Overall, 90-day outcome was favourable and the results appear promising. To optimise patient selection, future trials will need to test simplified clinical scores combined with high-sensitivity biomarker assays, and it will have to be determined whether echocardiography and/or compression ultrasonography are also required before discharge. Furthermore, ongoing trials will show whether new oral anticoagulants are a safe and cost-effective option for managing patients out of hospital.     

Antimicrobial and antispasmodic activity of leaf extract and fractions of Stachytarpheta cayennensis

ObjectiveTo investigate the antimicrobial activity of the methanol leaf extract (ME), n-hexane fraction (HF), ethylacetate fraction (EF) and methanol fraction (MF), of Stachytarpheta cayennensis C. Rich (verbenaceae) as well as to ascertain the antispasmodic effects of the ME and the various fractions (HF, EF and MF) on acetylcholine (Ach) and histamine (H) induced contractions on isolated guinea pig ileum.MethodsThe in vitro agar well diffusion method was used for the antimicrobial studies while the isolated tissue method was employed for the antispasmodic test. Organisms used were all clinical isolates of Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella paratyphi, Candida albicans and Aspergillus niger.ResultsThe extract and fractions exhibited dose dependent inhibition against all the bacteria tested and also exhibited insignificant antifungal activity against Candida albicans and Aspergillus niger. The minimum inhibitory concentration (MIC) of the extract and fractions (mg/mL) on Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella paratyphi respectively were ME 5.62, 14.12, 22.38, 2.11; EF 1.25, 6.30, 9.40, 9.40 and MF 3.98, 8.81, 39.80, 21.13. The n-hexane fraction exhibited MIC of 1.07 mg/mL against only Bacillus subtilis. The extract and fractions exhibited significant (P< 0.05) dose dependent attenuation of contractions induced by acetylcholine and histamine on isolated guinea pig ileum. Concentrations of the extract and fractions (μg/mL) which evoked 50% inhibition of maximal response exhibited by Ach were ME 0.64, HF 0.16, EF 0.08 and MF 0.15, while that of histamine included ME 5.12, HF 0.16, EF 0.04 and MF 0.64. Preliminary phytochemical studies on the extract and fractions indicated the presence of carbohydrates, alkaloids, saponins, flavonoids, steroids and terpenoids.ConclusionsThe extract and fractions of Stachytarpheta cayennensis possessed both antibacterial and antispasmodic effects confirming the claimed use in folkloric medicine for wound healing and gastrointestinal ulceration.