Difficult arterial cannulation in children: is a near-infrared vascular imaging system the answer?

BACKGROUND: Arterial cannulation is a common anaesthetic procedure that can be challenging and time-consuming in small children. By visualizing the position of the radial artery, near-infrared vascular imaging systems (NIRVISs) might be of assistance in arterial cannulation. The present study evaluates the effectiveness of an NIRVIS in arterial cannulation in infants. METHODS: An observational study was conducted in patients up to 3 yr old, undergoing arterial cannulation before cardiothoracic surgery. Arterial cannulation was performed as usual in 38 patients, and subsequently with the NIRVIS in 39 patients. RESULTS: The time to successful cannulation was 547 s (171-1183) without and 464 s (174-996) with the NIRVIS (P=0.76) and the time to first flashback of blood was 171 s (96-522) and 219 s (59-447), respectively (P=0.38). There was a tendency in favour of the NIRVIS in success at first attempt: 12/38 and 7/39, respectively (P=0.29) and in the number of punctures: 6 (2-12) and 3 (1-7), respectively (P=0.10). CONCLUSIONS: The present study did not show a significant clinical improvement when NIR light was used during arterial cannulation in small children. There is a large difference between time to first flashback of blood and time to successful cannulation, indicating that inserting the cannula, and not localizing the artery, is the main difficulty in arterial cannulation in children.

Central nervous system inflammation and neurological disease in transgenic mice expressing the CC chemokine CCL21 in oligodendrocytes.

To study the biological role of the chemokine ligands CCL19 and CCL21, we generated transgenic mice expressing either gene in oligodendrocytes of the CNS. While all transgenic mice expressing CCL19 in the CNS developed normally, most (18 of 26) of the CCL21 founder mice developed a neurological disease that was characterized by loss of landing reflex, tremor, and ataxia. These neurological signs were observed as early as postnatal day 9 and were associated with weight loss and death during the first 4 wk of life. Microscopic examination of the brain and spinal cord of CCL21 transgenic mice revealed scattered leukocytic infiltrates that consisted primarily of neutrophils and eosinophils. Additional findings included hypomyelination, spongiform myelinopathy with evidence of myelin breakdown, and reactive gliosis. Thus, ectopic expression of the CC chemokine CCL21, but not CCL19, induced a significant inflammatory response in the CNS. However, neither chemokine was sufficient to recruit lymphocytes into the CNS. These observations are in striking contrast to the reported activities of these molecules in vitro and may indicate specific requirements for their biological activity in vivo.

Unexpected birth trauma with near fatal consequences.

Rupturing of the liver due to delivery is an uncommon but severe birth trauma. Although described in the preterm neonate with very low birthweight or after complicated delivery, we present a case of capsular liver haemorrhage in a term newborn with normal birthweight after a seemingly uncomplicated delivery. The infant presented with severe shock and petechiae as first symptoms and initial therapy was based on the hypothesis of sepsis. Clinical suspicion of liver haemorrhage a few hours later was confirmed with abdominal ultrasound. Since shock was not amenable to fluid replacement therapy, the haemorrhage had to be managed surgically. Even without evidence of birth trauma, intra-abdominal bleeding must always be suspected in a newborn with suddenly prevailing shock and unexpected anaemia.

Vacuolation in renal tubular epithelium of Cd-1 mice: an incidental finding.

Prominent cytoplasmic vacuoles were observed in renal tubular epithelial cells of the outer medulla in several kidneys from test article-dosed mice (Crl:CD-1 (ICR)BR VAF/PLUS) during routine light microscopic (LM) examination. Because the vacuolar change was detected infrequently and was not found in any control mice from that study, it was not clear whether the vacuolation represented a drug-induced change. To address this question, kidney sections from mice from multiple unrelated studies were examined by LM for similar vacuolar changes. Vacuolation was seen by LM in 2.3% of the control and 2.8% of the test article-dosed mice. Transmission electron microscopy (TEM) was also performed on kidneys with prominent light microscopic vacuoles in 5 control mice and 2 test article-dosed mice to further characterize the vacuoles. Ultrastructurally, the vacuoles contained fibrillar and finely stipled granular material or membranous whorls. Kidneys from control mice lacking light microscopic evidence of vacuolation had smaller vacuoles containing similar material when examined by TEM. Because vacuoles were present in both control mice and test article-dosed mice, it was concluded that the vacuoles were incidental and unrelated to compound administration. These studies also demonstrated that vacuoles can be expected to be observed by LM examination in 2-3% of Crl:CD-1 (ICR)BR VAF/PLUS, mice.

Mycobacterium tuberculosis infection of a native polycystic kidney following renal transplantation.

BACKGROUND: Tuberculosis is a recognized complication following renal transplantation. Patients with autosomal dominant polycystic kidney disease are increasingly being offered renal transplantation as an alternative to chronic hemodialysis. These patients are uniquely susceptible to serious upper urinary tract infections that are associated with significant morbidity and mortality. While involvement with gram-negative organisms is well described, mycobacterial infection of native polycystic kidneys after transplantation has not been addressed. METHODS: A case report of a renal transplant recipient who suffered an isolated Mycobacterium tuberculosis infection of a native polycystic kidney and a literature review. RESULTS: Despite appropriate drug therapy, the infection proved refractory, and the patient required nephrectomy. CONCLUSIONS: Mycobacterial tuberculosis, though not common, must be recognized as a potential source of infection of native polycystic kidneys in immunocompromised transplant recipients. Similar to the pattern observed with more common pathogens, these infections may be difficult to eradicate with standard antimicrobial drug regimens.

Short report: a case of fibrosing mediastinitis caused by Wuchereria bancrofti.

Wuchereria bancrofti is a mosquito-borne filarial nematode that commonly invades lymphatic vessels. Common clinical manifestations include elephantiasis, orchitis, epididymitis, and chyluria. This report concerns an Egyptian man who developed superior vena cava syndrome secondary to a mediastinal mass that was found to contain a filarial nematode consistent with W. bancrofti. This is the first case, to our knowledge, of this parasite causing fibrosing mediastinitis.

Successful treatment of fungal prosthetic valve endocarditis: case report and review.

We report a case of Candida albicans prosthetic valve endocarditis in a patient who was still alive 1 year following a homograft aortic root and valve replacement and antifungal therapy. Only 33 other cases of successfully treated fungal prosthetic valve endocarditis have been reported. We review these 33 cases and six cases of late recurrence following treatment, as well as the clinical features, diagnosis, and options for treatment of fungal prosthetic valve endocarditis.

Computed three-dimensional reconstruction of median-eminence capillary modules: image alignment and correlation.

Image alignment is an absolute requirement for three-dimensional (3-D) reconstruction from serial sections, and Fourier correlation is the most powerful way to compute alignments. The rotational and translational components of misalignment can be corrected by an iterative correlation procedure, but for images having significant differences, alignment can fail with a likelihood proportional to the extent of the differences. We found that translational correction was determined much more reliably when low-pass filters were applied to the product transforms from which the correlations were calculated. Rotational corrections based on polar analyses of the auto-correlations of the images instead of on the images directly contributed to more accurate alignments. These methods were used to generate 3-D reconstructions of brain capillary modules from serial-section mosaics of digitized transmission electron micrographs.

Neurocysticercosis in an Orthodox Jewish community in New York City.

BACKGROUND AND METHODS: From June 1990 through July 1991, intracerebral infection with the larval stage of the pork tapeworm Taenia solium was diagnosed in four unrelated persons in an Orthodox Jewish community in New York City. None of the patients had eaten pork, and only one had traveled to a country in which T. solium infection was endemic. We investigated this outbreak, screened serum samples from family members and household contacts for antibodies to cysticercosis, and examined stool specimens from household employees for eggs of taenia species. RESULTS: The four patients had recurrent seizures and brain lesions that were radiologically consistent with the presence of cysticerci. The diagnosis was confirmed in two patients by a brain biopsy, and in two by immunoblot assays for cysticercus antibodies. Of 17 immediate family members screened serologically, 7 from two families had cysticercus antibodies. Magnetic resonance imaging of the brain showed cystic lesions in two of the seropositive family members, one of whom had had a seizure. Examinations of six domestic employees from all four households revealed an active infection with taenia species in one and a positive serologic test in another. Since these women had recently emigrated from Latin American countries where T. solium infection is endemic, they were the most likely sources of infection in the members of these households. CONCLUSIONS: A diagnosis of neurocysticercosis should be considered in patients with seizures and radiologic evidence of cystic brain lesions, even in those who do not eat pork and who have not traveled to a country in which T. solium infection is endemic. Recent emigrants from countries in which T. solium infection is endemic should be screened for tapeworm infection in their stools before they are employed as housekeepers or food handlers.

Computed alignment of dissimilar images for three-dimensional reconstructions.

Three-dimensional reconstructions from serial section images require the accurate registration of those images. Image correlation is the most powerful computed alignment method and its performance on identical images, or parts thereof, has been thoroughly studied. Correlation alignments of complex, dissimilar images can fail, however, with a likelihood proportional to the magnitude of the differences. We report that alignments can be computed more reliably and more accurately (higher-valued correlation coefficients) by the combined use of lowpass-filtered product transforms (from which the correlation functions are formed), autocorrelation correction of rotational misalignment, and covariance correction of translation misalignment. A simple rule is proposed for the lowpass filter cutoff radius depending on measures of the images' differences. These methods are demonstrated with a reconstruction of a capillary loop in the median eminence of the hypothalamus.

Oral fluconazole therapy for patients with acquired immunodeficiency syndrome and cryptococcosis: experience with 22 patients.

PURPOSE: Cryptococcus neoformans causes infections in up to 10 percent of patients with the acquired immunodeficiency syndrome (AIDS). Nearly 50 percent of AIDS patients with previously treated cryptococcal meningitis will experience a relapse within six months. To reduce the likelihood of relapse, a maintenance regimen of amphotericin B is often administered weekly. However, the drug's intravenous route of administration and considerable toxicity have led to a search for alternative antifungal agents. In this report, we document our experience with fluconazole, a new oral triazole antifungal agent. PATIENTS AND METHODS: Twenty-two patients with AIDS and various forms of cryptococcosis were treated in an open-label study with 50 to 400 mg/day of fluconazole. The following laboratory studies were done on a monthly basis: complete blood cell count, liver function tests, serum creatinine level, serum cryptococcal antigen level, and serum fluconazole level. Lumbar puncture was performed in patients with meningitis every four to eight weeks to evaluate cerebrospinal fluid cryptococcal antigen, India ink preparation findings, fungal culture, fluconazole level, and protein, glucose, and cell count. RESULTS: Of seven patients with active culture-positive infections, four showed clinical and microbiologic responses (three of four with meningitis, one of three with extraneural cryptococcosis). Fifteen patients who had already undergone successful amphotericin B therapy for either meningitis (n = 14) or pneumonia (n = 1) received fluconazole as prophylaxis against relapse. Fourteen patients remained free of infection during 11 to 64 weeks of suppressive therapy; one patient with meningitis experienced relapse after 26 weeks of treatment. Reverse reactions were limited to increases in hepatic enzyme levels in four patients. CONCLUSION: These results appear sufficiently encouraging to warrant further trials of this oral agent in the suppression of chronic cryptococcosis and perhaps in the treatment of acute infection.

Update on spinal epidural abscess: 35 cases and review of the literature.

Thirty-five cases of spinal epidural abscess were evaluated retrospectively and compared with 153 cases reported in the literature. As in other series, Staphylococcus aureus was the major pathogen. Patients with acute abscesses had fever, leukocytosis, and purulence at surgery. Patients with chronic abscesses had less fever and leukocytosis, more granulation tissue at surgery, and a greater delay in diagnosis but retained the potential for rapid neurologic deterioration. In contrast to other studies, abscesses in both the lumbar and anterior spinal compartments and patients with specific sources of infection occurred with greater frequency. Myelography was the diagnostic method of choice. Only four of nine patients had diagnostic computed tomography. Earlier diagnosis and treatment led to a significant improvement in outcome. Both steroid administration and greater neurologic impairment adversely affected outcome. Neurologic improvement following surgery was dependent on the duration of the deficit. A combination of antibiotics and surgical drainage remains the treatment of choice.

Computed tomography of renal aspergillosis.

The CT and sonographic findings of a case of localized, invasive aspergillosis of the kidney are presented.

Conversion of a homogeneously methicillin-resistant strain of Staphylococcus aureus to heterogeneous resistance by Tn551-mediated insertional inactivation.

Plasmid pRN3208, thermosensitive for replication, and carrying the erythromycin transposon Tn551, was used for insertional inactivation of methicillin resistance in a highly and homogeneously resistant strain of Staphylococcus aureus. Two kinds of insertionally inactivated cells were obtained. Cultures of the major class contained highly methicillin resistant cells with a frequency of about 10(-3) to 10(-4), produced DNA with methicillin resistance transforming activity, and also produced penicillin binding protein 2a, the 78 kd low affinity penicillin binding protein characteristic of methicillin resistant Staphylococcus aureus, in apparently normal quantities. The single member of class B had no detectable methicillin resistant cells (less than 10(-8)) with an MIC greater than 1 micrograms/ml, contained no DNA with methicillin resistant transforming activity and no penicillin binding protein 2a. The data suggest that in the class A cells insertional inactivation did not affect the structural gene(s) of methicillin resistance but a regulatory locus or loci needed for the homogeneous expression of resistance.

Expression of methicillin resistance in heterogeneous strains of Staphylococcus aureus.

The phenotypic expression of methicillin resistance was studied in a number of clinical isolates and laboratory strains of Staphylococcus aureus. The methicillin-resistant S. aureus strains could be divided into three classes, homogeneous, heterogeneous, and thermosensitive heterogeneous methicillin-resistant S. aureus, on the basis of their plating efficiencies at 30 or 37 degrees C on methicillin-containing agar plates. Heterogeneous strains of methicillin-resistant S. aureus were composed of two subpopulations: a small minority of cells (10(-5) to 10(-3); MIC, 600 to 1,000 micrograms/ml) that expressed resistance to high concentrations of methicillin at 37 degrees C, and a majority of cells (MIC, 5 micrograms/ml) that remained susceptible to the drug at 37 degrees C. Cultures of a thermosensitive heterogeneous strain were able to grow in the presence of high concentrations of methicillin, provided that the growth temperature was 30 degrees C. Such cultures lost their phenotypic resistance within 30 min (i.e., in less than one doubling time) after the growth temperature was shifted to the nonpermissive 37 degrees C. Shift of the temperature of the culture in the reverse direction (37 to 30 degrees C) resulted in an equally rapid expression of phenotypic resistance. The majority of the cells in such heterogeneous strains may be considered heat (or salt) conditional in their phenotypic expression of methicillin resistance. Both heterogeneous and thermosensitive heterogeneous strains, irrespective of their temperature of cultivation and degree of phenotypic resistance, contained detectable quantities of the 78-kilodalton penicillin-binding protein 2a (PBP 2a) that previous studies have suggested is a biochemical correlate of methicillin resistance in homogeneous strains of methicillin-resistant S. aureus. However, in contrast to the homogeneous stains, in heterogeneous and thermosensitive heterogeneous isolates the ability to synthesize PBP 2a is apparently not sufficient to provide a resistant phenotype. In these strains some additional, as yet undefined factor(s) is also needed for the expression of methicillin resistance.