Magnesium interaction with the surface of calcite in seawater.

Magnesian calcite overgrowth containing 4 (+/- 2) mole percent magnesium carbonate forms on calcite exposed to natural seawater near the ocean surface. This magnesian calcite is approximately 30 percent less soluble in seawater than pure calcite. The formation of the magnesian calcite of reduced solubility may have a major influence on calcite accumulation in deep sea sediments.

Direct detection of Epstein-Barr viral antigen in nasopharyngeal swabs from patients with infectious mononucleosis.

OBJECTIVE: To determine whether direct immunologic detection of Epstein-Barr virus (EBV) early antigen diffuse component (EA-D) from nasopharyngeal swabs is a feasible approach to the development of a rapid diagnostic test for infectious mononucleosis (IM). METHODS: Nasopharyngeal swabs from 20 patients presenting with a presumptive diagnosis of IM (having the classic triad of symptoms-acute pharyngitis, fever, and lymphadenopathy) and 5 controls were assayed for EA-D. EBV serologic testing and a heterophil antibody titer (HAT) test also were performed. EA-D was assayed by polyacrylamide gel electrophoresis and subsequent transfer to a nylon membrane, followed by immunoblotting with a monoclonal antibody. RESULTS: EA-D was detected in 17 of 20 patients (85%) with presumptive diagnoses of IM and in 1 of 5 normal subjects and was highly significant in predicting IM (p < 0.01). There was no significant difference in numbers of positive and negative results using either EA-D assay or HAT test in patients with IM (p < 0.35). Pharyngeal exudate in the 17 pharyngitis patients with this variable documented was significantly correlated with positive EA-D (p < 0.01), but not with the HAT test (p < 1.00). CONCLUSIONS: Immunologic detection of EBV-derived antigens from nasopharyngeal swabs is a potential early diagnostic tool for clinically suspected IM. Sensitivity and specificity in pediatric and adult populations, patients with other viral etiologies, and patients with streptoccocal pharyngitis should be determined in subsequent investigations.

Spontaneous rupture of a vesicourachal diverticulum manifesting as acute abdominal pain.

Urachal abnormalities are rare clinical entities. This article reports a case of a spontaneously ruptured vesicourachal diverticulum manifesting as acute abdominal pain in a healthy 38-year-old man. The embryology, clinical diagnosis, and management of urachal abnormalities are discussed. Emergency physicians should include this clinical entity in their differential diagnoses of patients who develop acute abdominal pain in the absence of trauma, especially when the pain immediately follows a maneuver that increases intra-abdominal pressure.

Detection of Mycoplasma gallisepticum by direct immunofluorescence using a species-specific monoclonal antibody.

A monoclonal antibody against Mycoplasma gallisepticum (MG) (strain S6) was prepared in mice and identified as isotype IgG1 by standard procedures. Although it did react at high titers (1:100,000) in the enzyme-linked immunosorbent assay (the original method for its identification), it failed to react in the agglutination, hemagglutination-inhibition, and growth-inhibition tests. When conjugated to fluorescein isothiocyanate, the monoclonal antibody reacted with the homologous and eight "atypical" strains of MG but not with M. meleagridis or M. synoviae in the direct fluorescent-antibody test. This reagent may be useful for detecting field infections involving atypical strains of MG.

Bacteria isolated from lymph nodes of California slaughter swine.

Lymph nodes from 280 slaughter swine from 9 California ranches were examined for the presence of aerobic microflora. Genera of interest which were isolated (and percentage of animals from which they were isolated) included Salmonella (4.3%), beta-hemolytic streptococci (8.2%), Mycobacterium avium-complex (6.4%), Corynebacterium pyogenes (0.4%), and Aeromonas hydrophila (5.7%). Patterns of bacterial isolations from swine herds may be of assistance in predicting herd health problems.

A physiological role for tRNA nucleotidyltransferase during bacteriophage infection.

Bacteriophage infection of E. coli cells deficient in the enzyme tRNA nucleotidyltransferase (cca mutants) resulted in greatly decreased production of viable progeny phage compared to wild type cells. This decrease amounted to as much as 90% in the case of T-even bacteriophages, and 50-65% for T-odd bacteriophages. However, infection by the RNA phages, Qbeta and f2, was unaffected by the cca mutation. Examination of T4 infection of cca hosts indicated that phage development proceeded normally, that near-normal numbers of progeny particles were formed, but that most of these particles were non-viable. Possible functions for E. coli tRNA nucleotidyltransferase during bacteriophage infection are discussed.

Synthesis of functional bacteriophage T4-delayed early mRNA in the absence of protein synthesis.

When Escherichia coli B207 is grown either aerobically or under limited aerobic conditions, pretreated with chloramphenicol to block protein synthesis, and then infected with bacteriophage T4, the phage RNA which accumulates, termed "immediately early" (IE), contains the transcripts of a limited number of prereplicative genes. Among the transcripts which accumulate is the mRNA which serves as a template for deoxycytidylate hydroxymethylase (HMase) synthesis. Among the prereplicative gene transcripts which do not accumulate under these conditions are deoxycytidine triphosphatase (dCTPase), alpha-glucosyl transferase (alphg-gt), and deoxynucleotide kinase (kinase); these genes have been termed "delayed early" (DE). In contrast, when protein synthesis is inhibited by depleting aerobically grown E. coli B207 of K+, both IE and DE T4 RNA accumulate, but these transcripts do not contain functional HMase, dCTPase, alpha-gt, or kinase mRNA's. However, if E. coli is grown under conditions of limited aeration and then depleted of K+ prior to T4 infection, the T4 RNA which accumulates contains both IE and DE transcripts and functional HMase, dCTPase, and alpha-gt mRNA's. Functional kinase mRNA does not accumulate under these conditions. The results of these experiments indicate that the synthesis of functional DE RNA in the absence of simultaneous protein synthesis, depends on the physiological condition of the cells and the way in which protein synthesis is inhibited. In addition, data is presented which suggests that extensive transcription of DE genes in the absence of protein synthesis results in the inhibition of transcription of certain IE genes.

Trichinosis: infrequent diagnosis or frequent misdiagnosis?

Trichinosis, a disease of wild and domestic animals caused by the nematode Trichinella spiralis, is an infrequently diagnosed infection in human beings. We present the case of a 33-year-old man with trichinosis whose diagnosis was complicated by the presence of maxillary sinusitis.

Transnasal butorphanol in the emergency department management of migraine headache.

Transnasal butorphanol (TNB) is a mixed agonist-antagonist opioid that has recently been released for the treatment of painful conditions. Patients with a history of migraine diagnosed in either of two emergency departments (EDs) with a moderate or severe migraine were eligible for this prospective study. Patients received 1 mg of TNB at time zero and again in 45 minutes if needed. Twenty-five patients were studied. Pain intensity was measured on a 10-cm visual analog scale. Mean pain intensity was significantly decreased at 15 minutes and declined from 7.9 +/- 1 cm initially to 2.5 +/- 3.3 cm at 90 minutes. Sixty percent of the patients required no further treatment. Thirty-six percent experienced side effects, with all but 1 being mild or moderate. Seventy-five percent rated the treatment as good, very good, or excellent, and 71% would prefer to receive TNB for future migraines over other treatment options. TNB offers rapid, effective pain relief to the majority of ED migraine patients.

Increased lithogenicity of bile on fasting in normal subjects.

The effect of fasting on bile lithogenicity was studied in 19 normal men and 22 normal women. The molar percentages of bile acid, phospholipid, and cholesterol, determined after random overnight fasts of 9, 12, and 16 hr, were plotted on triangular coordinates. The molar percentage of cholesterol increased in both men and women. Analysis using Admirand and Small's criteria for cholesterol saturation revealed that 4.50% of normal women were lithogenic at 9.1 hr and 54.5% at 16.5 hr (P less than 0.005). A similar trend in men was not significant. The mean values for both sexes were lithogenic at 16 hr only. Lithogenic bile was present in 4 men and 1 woman at 9 hr fasting and became more lighogenic with longer fasting. Analysis using the criteria of Hegardt and Dam revealed an increased proportion of both sexes moving into the metastable-labile and supersaturated zones on fasting, again with significant changes for women (P less than 0.01). The duration of fasting is important in interpreting the presence of lithogenic bile; although more pronounced in women, both sexes showed increased cholesterol saturation in bile with fasting.

Ultrasound interpretation of hydronephrosis is improved by a brief educational intervention.

Nineteen emergency medicine (EM) physicians (14 residents and 3 attendings) from an EM residency program which teaches ultrasound as part of the curriculum, were asked to rate 40 ultrasound scans showing different degrees of kidney hydronephrosis, first solely on the basis of their prior knowledge and experience. One week later, after a brief 15 minute lecture on a new objective method to read degrees of hydronephrosis, the same EM physicians were again asked to rate the 40 ultrasounds. One month later, to assess retention of the method, the same physicians were asked to read the same scans using the objective method presented 1 month prior. The three readings were compared with each other, and then each with a gold standard established for the study. Agreement of the group regarding scan interpretation improved and was maintained after the educational intervention (multirater kappa + .19, .32, and .32 for the three tests administered). When the differences between each week's readings and the gold standard were assessed, differences decreased with each successive test, and were statistically significant with the third test (P = .029). We conclude that our brief educational intervention improves agreement among physicians in readings of ultrasound scans and also significantly increases accuracy in readings when compared with a gold standard.

Wound infection rate and irrigation pressure of two potential new wound irrigation devices: the port and the cap.

The objectives of this study were to determine the speed of irrigation and the infection rate of two new irrigation devices. In the clinical portion of this two-part study, 208 patients with traumatic wounds were randomized to one of two new irrigation device groups, the cap/bottle or the port/bag, to determine irrigation times and infection/complication rates. Wounds were irrigated in less than 4 minutes in 97% of patients using a mean of 786 mL. The combined infection/complication rates were: port group, 1 of 99 (1%); cap group, 4 of 108 (4%), P = .356. In part II, 9 male and 8 female medical volunteers were timed in the delivery of 250 mL of saline into a graduated cylinder, using four different irrigation set-ups. Mean time for 250 mL and calculated stream pressures (psi) were: (1) cap/bottle, 12.9 seconds, 1.5 psi; (2) port/bag, 11.2 seconds, 2.0 psi; (3) syringe/catheter, 113.2 seconds, 8.2 psi; and (4) syringe/needle, 175.4 seconds, 7.3 psi (time and psi: P < .05 for all pairwise comparisons except cap versus port). Rapid irrigation and infection rates comparable with standard devices used in wound irrigation suggest that the new devices may prove to be valuable tools in emergent wound care.

Rapid oral hydration results in hydronephrosis as demonstrated by bedside ultrasound.

STUDY OBJECTIVE: To determine whether vigorous oral hydration (20 mL/kg) causes hydronephrosis as determined by bedside ultrasound. METHODS: We conducted a prospective laboratory trial in 35 healthy volunteers weighing less than 90 kg and between the ages of 18 and 50 years. The right kidney of the volunteers was scanned by emergency physicians at time 0 both before and after voiding, and the volunteers then drank 20 mL/kg of bottled water. The kidney was scanned in the transverse and sagittal planes both before and after voiding at 60 and 90 minutes after completion of the water load. The scans were interpreted by a physician trained and credentialed in emergency ultrasound, blinded to the volunteers' identity, the time of the scan, and the volume of urine voided by the subject. Images were rated as to the degree of hydronephrosis according to literature-established criteria, as follows: grade 0=no hydronephrosis, grade 1=mild, grade 2=moderate, and grade 3=severe hydronephrosis. RESULTS: Hydronephrosis was present in 3 (8.6%) of the 35 subjects at time 0 (prehydration), 24 (68.6%) at 60 minutes, and 20 (57.1%) at 90 minutes. Overall, hydronephrosis occurred at least once in 28 (80%) of the 35 subjects after oral hydration compared with 3 (8.6%) of the 35 subjects before hydration. Hydronephrosis was found to be significantly related to forced hydration for all posthydration times (60 minutes, 90 minutes, and 60+90 minutes combined) versus prehydration time 0 (P <.001). CONCLUSION: Without prior fluid intake, even mild degrees of hydronephrosis were relatively uncommon, and seen in only 8.6% of study patients. In the presence of vigorous oral hydration, however, mild or moderate hydronephrosis is a frequent occurrence seen at least once in 80% of our study of healthy volunteers after hydration. Caution is warranted in this setting when interpreting mild or moderate hydronephrosis found on bedside ultrasound by emergency physicians.