The evoked K-complex: all-or-none phenomenon?

The functional significance and topographical variation of the different components of the evoked K-complex were examined. In the first experiment, the intensity of the stimulus (80 and 60 dB SPL) and its rise-and-fall time (2 and 20 milliseconds) were manipulated during nonrapid eye movement sleep. In the second experiment the tonal frequency (500, 1,000 and 2,000 Hz) of the stimulus was manipulated. In the first experiment, nine stimuli were presented every 10 seconds, whereas in the second, 20 consecutive stimuli were presented. The evoked K-complex consisted of two different negative components peaking at approximately 350 and 550 milliseconds, respectively, and followed by a positive component peaking at approximately 900 milliseconds. K-complexes were easier to elicit for high-intensity fast rise-and-fall time stimuli than for low-intensity slow rise-and-fall time stimuli. The probability of occurrence was not affected by the tonal frequency of the stimulus. When a K-complex was evoked, the amplitude and latency of N350, N550 and P900 remained invariant regardless of its intensity, rise-and-fall or its tonal frequency. The N550-P900 portion of the K-complex therefore appears to be an all-or-none phenomenon. On trials in which a K-complex could not be elicited, N350 was still visible although much attenuated. In these trials, its amplitude was further reduced when stimulus intensity was lowered. N350 might need to reach a certain critical threshold before the much larger N550-P900 complex is elicited.     

Use of intracavity saline instillation and transvaginal ultrasonography to detect tamoxifen-associated endometrial polyps.

There is sometimes a discrepancy between the apparent thickness of postmenopausal endometria, as determined by transvaginal ultrasonography, and the examination of endometrial biopsies. We describe a case which showed that tamoxifen (20 mg/day over 12 months) decreased impedance to blood flow in the uterine arteries and increased the apparent thickness of the endometrium. Conversely, the analysis of biopsies suggested the presence of an atrophic endometrium. The introduction of sterile saline into the uterine cavity during a repeat ultrasound scan revealed the presence of a large, free-floating endometrial polyp, which was subsequently difficult to see by hysteroscopy.     

Diagnosis and management (by subxiphoid pericardiotomy) of large pericardial effusions causing cardiac tamponade.

To determine the clinical features, course and outcome of patients with cardiac tamponade, 57 consecutive patients with new, large pericardial effusions were prospectively studied. Twenty-five patients (44%) developed cardiac tamponade with venous hypertension and a pulsus paradoxus greater than 10 mm Hg. Electrocardiography, radiographic studies and echocardiography did not differentiate patients with and without tamponade. All 57 patients underwent thorough diagnostic evaluation followed by subxiphoid pericardial biopsy and drainage. A diagnosis was obtained in 53 patients (93%). Collagen vascular disease was significantly more frequent in the 25 patients with than in the 32 without cardiac tamponade (24 vs 3%; p less than 0.05). The frequency of malignant and uremic effusions was equal in both groups, whereas radiation-induced effusions seldom produced tamponade. At 1-year follow-up, 3 patients (12%) with tamponade had recurrent effusions, and 1 needed reoperation. This was not significantly different from the 32 patients without tamponade. Twelve-month mortality was also similar in both groups (36 vs 44%). This prospective series disclosed several unexpected findings: (1) Cardiac tamponade occurred in almost 50% of patients with new large pericardial effusions; (2) both malignancy and collagen vascular disease occurred with equal frequency as etiologies, whereas radiation-induced tamponade was unusual; (3) thorough clinical evaluation resulted in few idiopathic etiologies; and (4) subxiphoid pericardiotomy was effective for both diagnosis and therapy of tamponade.     

Innovative endpoint determination system for antifungal susceptibility testing of yeasts.

Fungal infections and antifungal resistance are increasingly recognized. Antifungal susceptibility testing remains unstandardized, and a particularly important problem is endpoint determination. In this paper we propose the yeast metabolic reduction of the tetrazolium salt 2,3-bis(2- methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetraz olium hydroxide (XTT) as a colorimetric endpoint which is quantitative and objective. Amphotericin B, fluorocytosine, and fluconazole dose-response curves were obtained, and a metabolic MIC could be determined by using precise criteria.     

Erythropoietin levels in amniotic fluid and extraembryonic coelomic fluid in the first trimester of pregnancy.

OBJECTIVE: The aim was to measure erythropoietin levels in amniotic fluid and extraembryonic coelomic fluid from 7-12 weeks' gestation. SUBJECTS: Twenty healthy women with ultrasonographically normal first trimester pregnancies prior to surgical termination. METHODS: Paired samples of amniotic fluid and extraembryonic coelomic fluid were collected by transvaginal ultrasound guided needling. Erythropoietin was measured in both pregnancy fluids using a radioimmunoassay. RESULTS: There was a highly significant difference between erythropoietin levels in extraembryonic coelomic fluid (median level 15.45 mU/ml; range 6.8-32.1 mU/ml) and those in amniotic fluid (median 5.0 mU/ml; range < 5.0-5.8 mU/ml) (P < 0.0001; Mann-Whitney U-test). The levels of erythropoietin in maternal serum (median 15.4 mU/ml; range 5.6-29.4 mU/ml) were similar to those in the extra-embryonic coelom (P = 0.81; Mann-Whitney U-test). No relation was demonstrated between erythropoietin levels in amniotic fluid or coelomic fluid and stage of gestation. CONCLUSION: High levels of erythropoietin in coelomic fluid suggests that the hormone is involved in the process of human extraembryonic erythropoiesis. The exact regulatory role remains unknown.     

Psoas abscess following ingestion of psoas.

A case of right psoas abscess that was caused by duodenal perforation following the ingestion of a wooden skewer from a filet mignon is presented. Surgical repair of the perforation, drainage of the abscess and 5 days of intravenous antibiotics resulted in prompt recovery.     

Chest hair micrografts display extended growth in scalp tissue: a case report.

Conventional follicle harvesting techniques for hair transplantation are limited by the available scalp donor hair. The development of an innovative technique of microsurgical single follicular unit extraction has made it possible to exploit body hair grafts for scalp transplantation. This case study reports on 18 months of follow-up on a patient with extensive scalp scarring who underwent a transplantation procedure using donor chest hair. The photographically documented results show a change in the length of the chest hair measuring an average of 4 cm at transplant to 15 cm by 18 months post-transplant. The transplanted chest grafts provided an excellent cosmetic result for hair replacement.     

A performance curve for assessing change in Percentage of Consonants Correct Revised (PCC-R).

PURPOSE: Interpreting the rapidly changing speech skills of young children recovering from neurological injury is difficult because developmental expectations are generally available only at relatively lengthy intervals (e.g., 6 or 12 months). In this research note, the authors describe the process of generating a Percentage of Consonants Correct-Revised (PCC-R; L. D. Shriberg, D. Austin, B. A. Lewis, J. L. McSweeny, & D. L. Wilson, 1997a) performance curve and illustrate some of its applications for assessing change in performance over time. METHOD: The authors compiled mean PCC-R scores from 16 samples of typically developing children (18-172 months) and used curve fitting to test more than 11,000 statistical models of monthly growth in PCC-R. They selected a parsimonious and developmentally plausible model with R(2) = .9839 (p < .0005) and used it to generate the PCC-R, standard deviation, and standard error expected at each monthly age. RESULTS: The PCC-R performance curve distinguished among 65 children (37-57 months of age) diagnosed independently with normal or disordered speech with a high degree of success. More important, the PCC-R performance curve can be used to identify the points at which children (18-172 months) recovering from neurological injury achieve normal-range consonant production. CONCLUSION: The curve-fitting approach holds promise as a means of interpreting temporal variations in speech production at a finer grain than existing normative data currently allow.