Detection of borderline oxacillin-resistant Staphylococcus aureus and differentiation from methicillin-resistant strains

Eighty-eight Staphylococcus aureus clinical isolates meeting criteria for borderline oxacillin resistance (intermediate susceptibility or resistance to oxacillin but susceptibility to amoxicillin/clavulanic acid upon disk diffusion testing) were studied to determine optimal test techniques and conditions for differentiating borderline oxacillin-resistant Staphylococcus aureus (BORSA) from methicillin-resistant Staphylococcus aureus (MRSA). Further testing revealed three distinct resistance patterns: 61 strains (69%) consistently met BORSA criteria and had average beta-lactamase levels five- to six-fold higher than oxacillin-susceptible controls; 11 strains (13%) were markedly heteroresistant MRSA with delayed appearance of resistant colonies leading to spurious susceptibility to amoxicillin/clavulanic acid; 16 strains (18%) appeared to be oxacillin-susceptible on repetitive testing. Under conditions used to elicit intrinsic methicillin resistance in Staphylococcus aureus, a large percentage of BORSA appeared resistant to amoxicillin/clavulanic acid. This clearly shows that BORSA may be misidentified as MRSA while heteroresistant MRSA may appear to be BORSA. It is concluded that amoxicillin/clavulanic acid zone sizes should be measured after a full 24 hours of incubation, that susceptibility testing of Staphylococcus aureus under certain environmental conditions should be interpreted with caution, and that MIC testing is the most reliable technique for differentiating these two resistance patterns in Staphylococcus aureus.

Identification of a cis-acting element in human immunodeficiency virus type 2 (HIV-2) that is responsive to the HIV-1 rev and human T-cell leukemia virus types I and II rex proteins

A simian virus 40 late replacement vector encoding human immunodeficiency virus type 1 (HIV-1) gp120 (pGP120) was used to define a region within the HIV-2 genome that could work as a rev-responsive element (RRE). Our previous work showed that gp120 expression in this system required a functional RRE in cis and required the rev protein in trans (M.-L. Hammarskjöld, J. Heimer, B. Hammarskjöld, I. Sangwan, L. Albert, and D. Rekosh, J. Virol. 63:1959-1966, 1989). Using pGP120, we first mapped an RRE to a 1,042-base-pair (bp) Sau3a fragment in the env region of HIV-2. Both HIV-1 rev (rev1) and HIV-2 rev (rev2) could work in conjunction with this fragment. Further mapping showed that a 272-bp subfragment within the 1,042-bp region was sufficient as an RRE. Surprisingly, the smaller fragment worked only with the rev1 protein and not with its homologous rev2 protein. In addition, the rev2 protein failed to function together with the RRE from HIV-1. We also utilized this system to examine the ability of the rex genes of human T-cell leukemia virus types I and II to functionally substitute for rev. These experiments showed that complementation by both the rexI and rexII proteins required the presence of an RRE. The rex proteins worked well in conjunction with either the HIV-1 or the HIV-2 RRE (the 1,042-bp as well as the 272-bp fragment).

HIV-1-Related and Nonrelated Diseases among IV Drug Users and Sexual Partners

As part of a project to reduce risk of HIV-1 infection/transmission among IV drug users (IVDUs) and sexual partners (SPs) of IVDUs, individuals not currently in drug treatment were recruited, tested for HIV-1, and interviewed about risk factors for AIDS and history of various health conditions. Of the sexually transmitted diseases (STDs), gonorrhea, syphilis and genital sores were common. Of non-STDs, pneumonia, and hepatitis were reported most often. Among IVDUs, most STDs were more common in seropositives and subjects with multiple sexual partners. Among SPs, serostatus was related to gonorrhea and syphilis. IVDUs had more endocarditis and hepatitis than SPs, and overall, more STDs. These data suggest that IV drug-using and sexual behaviors need targeted interventions to reduce the prevalence of associated diseases.

Suppression of norepinephrine appearance rate in plasma by diazepam in humans

Studies demonstrating benzodiazepine-induced reductions in plasma norepinephrine (NE) have assumed that changes in circulating plasma NE closely parallel changes in sympathetic nervous system (SNS) activity and that benzodiazepines suppress SNS outflow. However, decreases in plasma NE could also result from increased removal of NE from plasma via neuronal uptake or tissue metabolism. This study used a tritiated norepinephrine ([3H] NE) isotope dilution technique for measurement of plasma NE kinetics to determine if the fall in plasma NE induced by a single dose of diazepam orally administered to eight psychiatrically-healthy volunteers was due to a fall in plasma NE appearance rate or an increase in plasma NE removal. Diazepam decreased plasma NE appearance, but not clearance, and also decreased plasma epinephrine and mean arterial pressure, memory performance and alertness. Plasma levels of diazepam were correlated with drug effects on memory and alertness but not cardiovascular or SNS effects.

Nursing application of Bobath principles in stroke care

The nursing approach in the care of stroke patients has a direct impact on functional outcome. Nursing application of Bobath principles in stroke care offers a nursing focus on involvement of the affected side; facilitation of normal tone, posture, and movement; and development of more normal function. A research study evaluating the functional gains of stroke patients demonstrated a significant level of functional improvement in those treated with Bobath principles over stroke patients treated with the traditional nursing approach. Practical methods for applying Bobath principles in patient care activities are described. These therapeutic methods provide nurses with the means to maximize stroke patients' potential and further influence their functional recovery.

Left ventricular function from end-systolic stress-shortening relations in mitral valve prolapse

Left ventricular (LV) function was studied from end-systolic stress-shortening relations in 13 patients with mitral valve prolapse (MVP). Studies were made noninvasively using M-mode echocardiography with blood pressure measurements on the right arm from a Baumanometer cuff. Fifteen age and sex-matched normal subjects formed the control group. LV end-diastolic dimension was normal in MVP, while shortening fraction (p less than 0.05) and velocity of circumferential fiber shortening (mean Vcf) in the short axis of the ventricle were increased (p less than 0.05). Ventricular afterload, as measured by meridional end-systolic stress was reduced in MVP (p less than 0.01) but the slope of the stress-shortening curve was not different form normal. The decrease in end-systolic stress was related to the severity of prolapse (r = 0.63, p less than 0.05). The study implied that mid- or basal LV contractility was normal in MVP. The increased shortening fraction of the LV minor axis was in keeping with geometrical changes and a reduced ventricular afterload.

A retrospective study of treatment of orbital floor fractures with the maxillary sinus approach

The Cook County Hospital, Chicago, Illinois, protocol for the management of orbital fractures is presented. Diplopia which fails to resolve in 1 week or appears after oedema subsides, enophthalmos or radiographic depression of the orbital floor, associated tripod fracture deformity, or purulent maxillary sinusitis are indications for surgery. The surgical procedure is a modification of the maxillary sinus approach, which includes the use of iodoform gauze packing, nasal antrostomy, a double layer oral closure and prophylactic antibiotics. A review of 102 patients treated surgically over a 6-year period is presented. Post-operative diplopia was 9% and there were minor complications in 3%, which were significantly lower than previously reported series of orbital fractures treated either non-operatively, or through an orbital exploration approach. No patient treated non-operatively required surgery in the future. The protocol presented can eliminate unnecessary exploration and yields excellent results with a simple surgical procedure.

Activity of novel aminocannabinoids in baboons

The axial and equatorial isomers of 7-(methylamino)hexahydrocannabinol (1 and 2) and 7-(dimethylamino)hexahydrocannabinol (3 and 4) were prepared by reductive amination of the corresponding cannabinoid aldehydes. The amines caused some tranquility in baboons but did not evoke the typical cannabimimetic syndrome caused by psychoactive cannabinoids. However the axial amines (1 and 3) but not the equatorial ones (2 and 4) caused bouts of scratching and yawning. The latter is a rare pharmacological effect hitherto not observed with other cannabinoids.

Earlobe repair: a new technique

An alternative technique to the Z-plasty for repair of the earlobe rim has been presented. The V-flap technique is easier to perform and serves the same purpose of preventing notching at the earlobe rim.

Prolactin, corticotropin, and gonadotropin concentrations following thermal injury in adults

The concentration of serum prolactin (PRL), plasma corticotropin (ACTH), serum follicle stimulating (FSH), and luteinizing (LH) hormones were measured in 28 adult burned patients (25 males and three females). Morning and night determinations were performed for each hormone. Serum PRL was elevated in males up to the fourth week after the thermal injury. Plasma ACTH increased significantly on the second day postburn and returned gradually to normal on the fifth; serum FSH and LH increased on day 1, then decreased significantly on day 2 and remained low for about 2 weeks. In females, while PRL increased significantly, the gonadotropins were slightly elevated and the ACTH remained within normal limits for the 3 days during which it was possible to study these patients. In all subjects the circadian rhythm of the four measured hormones showed significant variations from the normal pattern.

An intraocular lens carrier

An intraocular lens carrier for anterior and posterior chamber lenses has been developed. The device consists of a protective polypropylene envelope with an insertion leaf, which allows anterior chamber lenses to be inserted without iris or corneal touch and posterior chamber lenses to be guided into the ciliary sulcus or capsular bag with minimal or no haptic manipulation. +

Studies of left-ventricular function in anemia due to beta-thalassemia

Left-ventricular (LV) function was studied in 23 patients with anemia due to beta-thalassemia, of whom seven had thalassemia intermedia and the remainder thalassemia major. Two-thirds of the patients wih thalassemia intermedia and almost all the patients with thalassemia major were in clinical congestive heart failure. Despite this, resting measurements of ventricular size and systolic ventricular function were normal, indicating high-output cardiac failure. However, effort testing showed a flat response or decrease in the LV shortening fraction in patients with thalassemia major, and serial studies showed a decrease in the shortening fraction over a 4-yr period in some patients. LV diastolic function was studied by calculating peak LV filling rate and the pattern of LV filling in early diastole. Three patient with thalassemia major showed a pattern indicating abnormal LV distension. Since LV end-diastolic dimension was increased, volume overload was present in all patients. The results indicate that the following factors contribute to the genesis of cardiac failure in beta-thalassemia: 1) diminished response of systolic ventricular performance to exercise and later at rest; 2) ventricular volume overload; and 3) abnormal ventricular distension in diastole. Although the ventricular filling suggests abnormal LV compliance, the effect of right-ventricular volume overload or a pericardial factor cannot be excluded.

RBC and plasma levels of haloperidol and clinical response in schizophrenia

The authors conducted a fixed-dose study of haloperidol blood levels and clinical response in schizophrenic in patients and found that those with steady-state RBC haloperidol levels in the range of 2.4--5.4 ng/ml showed greater improvement than those with lower or higher levels. They found a similar , although nonsignificant, curvilinear relationship between plasma haloperidol levels and clinical response. These findings suggest that the relationship between haloperidol blood levels and clinical response fits a therapeutic window for the treatment of schizophrenia.

Echocardiography of the inferior vena cava in healthy subjects and in patients with cardiac disease

Echocardiograms were recorded from the inferior vena cava (IVC) in 45 subjects: 10 normal subjects, 8 patients with cardiac volume overload due to anemia, 4 with severe right heart failure, 6 with significant tricuspid incompetence (TI), 7 with pericardial effusion (PE) and 10 with left-sided cardiac disease. The IVC was readily identified on the echo recordings made 1 to 2 cm below the junction of the hepatic veins. In normal subjects a double wave form was present on the IVC echogram for each beat: the waves corresponded to the "a' and "v' waves of the IVC pressure pulse tracing. The IVC diameter decreased on inspiration (P less than 0.01), particularly of the "x' descent (P less than 0.001). In patients with severe right heart dysfuction, the IVC was dilated (TI: P less than 0.02; PE: P less thaN 0.003; CMO: P less than 0.001), having lost its waveform and with diminished respiratory variation. There was, however, considerable overlap between the normal subjects and the different patient groups. In two of the patients with tamponade, the IVC did not empty upon inspiration, and pericardiocentesis was followed by a return of the waveform and normal respiratory changes. IVC dimensions were normal in patients with anemia and in those with left heart disease. The results of the study showed that the echogram may provide simple and useful measurements of IVC size and function.

Quantitation of regional ventricular asynergy using real-time two-dimensional echocardiography

Real-time two-dimensional echocardiography was used to identify and quantitate regional left ventricular dysfunction in 12 patients with coronary artery disease. THe extent of regional ventricular asynergy was expressed as the percentage of the left ventricular circumference contracting abnormally. The findings were compared with those obtained from cardiac catheterization and left ventriculography. The severity and extent of echocardiographic asynergy correlated closely with that observed on the angiocardiogram (r = 0.96, P less than 0.001). There was also a significant relationship between echocardiographic and angiocardiographic ventricular volume (r = 0.81, P less than 0.001) and ejection fraction (r = 0.79, P less than 0.01). Real-time two-dimensional echocardiography provided a useful noninvasive technique for the identification and quantitation of the extent of regional ventricular dysfunction.

Left ventricular filling and emptying patterns in anemia due to beta thalassemia. A computer-assisted echocardiographic study

Patterns of left ventricular (LV) filling and emptying were studied in 17 patients with chronic anemia due to beta thalassemia and in 8 normal subjects. M-mode echocardiograms were recorded in each patient and digitization and computer analysis of the tracings provided data relating to the systolic and diastolic performance of the LV. LV diameter was increased. The rate, pattern and time relationships of LV systolic emptying were normal or increased in patients with thalassemia especially in those with thalassemia major requiring a large number of blood transfusions. Peak LV filling rate and the time course of early diastolic ventricular filling were also normal or increased in most patients but an abnormality of diastole was present in 3; this may have been due to abnormal early diastolic relaxation or to right-sided overload altering the LV filling pattern.

Long-term effect of verapamil in hypertrophic cardiomyopathy

We studied the long-term effects of oral verapamil (240-720 mg) daily on 10 patients with hypertrophic cardiomyopathy. Symptomatic improvement of chest pain or shortness of breath occurred in all the patients although 4 deteriorated after 1 year. Side effects occurred in 3 patients. The electrocardiogram improved in 4 subjects. Quantitative echocardiography showed a significant (P less than 0.05) decrease in left ventricular contractility (% delta S decreased from 44 +/- 9 to 38 +/- 9, mean +/- SD), septal hypertrophy (1.6 +/- 0.5 to 1.4 +/- 0.5 cm) and % thickening of the left ventricular free wall (79 +/- 29 to 57 +/- 22). There was also moderate evidence of improvement in left ventricular compliance; mitral valve EF slope increased from 38 to 55 mm/sec and left atrial diameter decreased.

Regional left ventricular ejection fraction from real-time two-dimensional echocardiography

We studied regional left ventricular contraction patterns and ejection fraction from real-time two-dimensional echocardiograms in 8 normal subjects, 11 patients with coronary artery disease and 2 with congestive cardiomyopathy. The ventricle was divided into 12 regions and for each region, we calculated ejection fraction using a method which integrated the incremental volumes of a series of hemicylinders constructed within that region. The data obtained were displayed graphically to provide a detailed picture of regional ventricular function. Normal subjects had a uniform regional ventricular pattern (regional ejection fraction 54-74%). In patients with coronary disease, we found varying degrees of regional ventricular contraction abnormalities. In congestive cardiomyopathy global hypokinesis was present, and regional ejection fraction was reduced in all areas (11-39%). The study showed that two-dimensional echocardiography is a useful non-invasive bedside technique which may provide detailed quantitative information relating to regional left ventricular contraction abnormalities.

Echocardiographic diagnosis of left anterior descending coronary artery disease and left ventricular asynergy

Interventricular septal (IVS) motion was studied by M-mode echocardiography in 60 patients to review the value of the technique in identifying left anterior descending (LAD) coronary artery disease. Abnormalities of IVS thickening and excursion were presented in 90% of patients with proximal LAD disease, whereas septal function was essentially normal in patients with distal LAD disease and in patients with disease of the right and/or circumflex coronary arteries. Abnormalities of IVS motion were greater in patients with a history of previous anterior wall infarction and/or the presence of angiographic left ventricular (LV) asynergy. There was no difference between patients with isolated or combined LAD disease, nor was there a difference between patients with complete or partial obstruction of the LAD, when more than 75% of the lumen was occluded. The echo was also useful in identification of anterior LV asynergy. Abnormal widening of the LV near the apex and abnormal septal movement in this area detected, with high sensitivity and specificity, patients with angiographic anterior wall asynergy.

Why quality assurance?

Quality assurance programs in radiology are essential and each radiologist must be committed to exert comprehensive efforts toward excellent quality control. Identification and evaluation of a radiological problem, corrective action, and good record keeping are essential features of a well-managed quality assurance program. This paper discusses the background and impact of these programs on providing safe radiologic services to patients.