Procedure guidelines for radionuclide myocardial perfusion imaging

Radionuclide myocardial perfusion imaging (MPI) is an established and non-invasive imaging technique with diagnostic and prognostic efficacy in the investigation of coronary artery disease. It is the only widely available test for assessing myocardial perfusion directly but there are variations in the way it is performed in different centres. Harmonization of practice, at least at a national level, is therefore essential, and clinical governance now makes it mandatory for practice to be based upon evidence whenever possible [ 1]. This is best achieved by expert analysis of the evidence and to this end the British Nuclear Cardiology Society (BNCS) in association with the British Cardiac Society (BCS) and the British Nuclear Medicine Society (BNMS) have developed procedure guidelines for tomographic myocardial perfusion imaging. A systematic literature search was performed and every effort was made to conform with the AGREE recommendations [ 2]. All recommendations are therefore based on either evidence from clinical studies, previous published guidelines or expert consensus of the writing and advisory groups. The guidelines cover the clinical indications of MPI, the methods used for stress testing, the radiopharmaceuticals and the injected activities and also issues related to acquisition, processing and interpretation of images. They do not cover the benefits or drawbacks of the technique in specific circumstances; neither do they address its cost effectiveness in clinical diagnosis and management nor its potential impact on clinical outcomes. The guidelines aim to assist medical practitioners and other health care professionals in recommending, performing, interpreting and reporting single photon emission computed tomography (SPECT) of myocardial perfusion.

Dermatomycoses caused by Nattrassia mangiferae in São Paulo, Brazil

Nattrassia mangiferae formerly known as Hendersonula toruloidea, is a phaeoid coelomycete described by Nattrass in 1933. We report five cases of N. mangiferae infections in São Paulo, Brazil. This fungus was isolated from interdigital lesions on the feet in one patient, toenails in three cases and fingernails in the other one. The infections were initially considered to be caused by a dermatophyte. Although there are only a few cases described in the medical literature, the five cases reported suggest that N. mangiferae should be taken into consideration in the differential diagnosis of tinea pedis infections.

Loss of lineage antigens is a common feature of apoptotic lymphocytes

The analysis of apoptosis in cell populations involves the detection of their specific lineage antigen (LAg) expression. This experimental approach relies on their assumed constant expression, but it is unclear whether such expression is actually maintained during cell death. We examined whether the loss of LAgs is a common feature of apoptotic lymphocytes and whether some might completely lose their LAgs. The changes in the expression of CD3, CD5, CD8, CD4, CD28, CD56, and CD19 were monitored in highly purified lymphocyte populations obtained by negative selection in a fluorescence-activated cell sorter. These were cultured for 24 h with or without phytohemagglutinin or staurosporin. For each LAg-positive subset studied, apoptosis was consistently more common among cells showing partial or total loss of LAg expression compared with cells maintaining their initial LAg levels. The kinetics of expression loss was rapid for CD8, CD56, and CD28, and more than 80% of initial expression was lost in the early stages of apoptosis but was slower for CD3, CD5, and CD4. For CD3 and CD5, expression was dependent on the apoptotic stimulus used. It is interesting that loss of antigen expression was independent of cell size. This phenomenon was also found in nonmanipulated, highly pure CD19 B lymphocytes of peripheral blood mononuclear cells from B chronic lymphocytic leukemia patients. Loss of LAg expression appeared to be a common feature of apoptotic lymphocytes under all the conditions assayed. The different kinetic patterns of LAg loss suggest apoptotic cells might actively regulate this process.

Hemophagocytic syndrome associated with retinoic acid syndrome in acute promyelocytic leukemia

A 56-year-old woman with an acute promyelocytic leukemia (APL) developed a severe all-trans-retinoic (ATRA) syndrome on day 17 of treatment. Shortly after, she presented a picture of pancytopenia, hepatosplenomegaly, increased triglycerides, ferritin, and liver enzymes. A bone marrow biopsy showed abundant macrophages and no evidence of leukemia. Tests for secondary hemophagocytic syndrome (HPS) were negative. A diagnosis of HPS was made. Treatment with dexamethasone and high-dose immunoglobulins was unsuccessful. Consolidation chemotherapy with idarubicin and ATRA rapidly reversed the HPS. The HPS in this patient could be related to the release of macrophage-stimulating cytokines by APL cells during ATRA syndrome.

Receptor model source apportionment of nonmethane hydrocarbons in Mexico City

With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC) to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas), asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

Basic statistics of PM2.5 and PM10 in the atmosphere of Mexico City

The high levels of fine particulate matter in Mexico City are of concern since they may induce severe public health effects as well as the attenuation of visible light. Sequential filter samplers were used at six different sites from 23 February to 22 March 1997. The sampling campaign was carried out as part of the project 'Investigación sobre Materia Particulada y Deterioro Atmosferico-Aerosol and Visibility Evaluation Research'. This research was a cooperative project sponsored by PEMEX and by the US Department of Energy. Sampling sites represent the different land uses along the city, the northwest station, Tlalnepantla, is located in a mixed medium income residential and industrial area. The northeast station, Xalostoc, is located in a highly industrialized area, Netzahualcoyotl is located in a mixed land use area, mainly commercial and residential. Station La Merced is located in the commercial and administrative district downtown. The southwest station is located in the Pedregal de San Angel, in a high-income neighborhood, and the southeast station located in Cerro de la Estrella is a mixed medium income residential and commercial area. Samples were collected four times a day in Cerro de la Estrella (CES), La Merced (MER) and Xalostoc (XAL) with sampling periods of 6 h. In Pedregal (PED), Tlalnepantla (TLA) and Netzahualcoyot1 (NEZ) sampling periods were every 24 h. In this paper the basic statistics of PM2.5 and PM10 mass concentrations are presented. The average results showed that 49, 61, 46, 57, 51 and 44% of the PM10 consisted of PM2.5 for CES, MER, XAL, PED, TLA and NEZ, respectively. The 24-h average highest concentrations of PM25 and PM10 were registered at NEZ (184 and 267 microg/m3) and the lowest at PED (22 and 39 microg/m3). The highest PM10 correlations were between XAL-CES (0.79), PED-TLA (0.80). In contrast, the highest PM2.5 correlations were between CES-PED (0.74), MER-CES (0.73) and TLA-PED (0.72), showing a lower correlation than the PM10 one. The results of the PM10 from 12.00 to 18.00 h at CES and MER presented the highest variability and also the highest median concentrations, meanwhile XAL showed them from 06.00 to 12.00 h. The highest variability and median concentrations of PM2.5 were from 06.00 to 12.00 h for the three stations.

Lung changes and cytokine levels in a model of experimental acute pancreatitis

AIM

Prognosis of acute pancreatitis is related mainly to systemic involvement. The establishment of this systemic inflammation is mediated by proinflammatory cytokines. Our aim is to study serum levels of some proinflammatory cytokines and the associated damage of the lung in a model of experimental acute pancreatitis.

EXPERIMENTAL DESIGN

Eighty seven male Wistar rats were divided into two groups: group A (control) with saline solution administration; group B with acute pancreatitis induced by intraperitoneal caerulein (50 mg/kg every hour, 4 doses). The animals were killed at 0, 2, 6 and 24 hours of the last dose of caerulein or saline solution. Pancreatic and pulmonary histology were examined, and serum levels of IL-1 beta, TNF-alpha and IL-6 were evaluated, as well as some laboratory parameters as indicators of systemic involvement.

RESULTS

The administration of caerulein induced an acute edematous pancreatitis without mortality and with a trend towards resolution in 24 hours. IL-1 beta in animals with acute pancreatitis showed significantly higher levels than in the control group at 6 hours. Serum transaminases, urea and creatinine were also significantly higher at 2 and 6 h. The group with acute pancreatitis showed histological lung damage all over the study.

CONCLUSIONS

In our model of acute pancreatitis we observed systemic involvement as judged by alterations of serum transaminases and parameters of renal function, as well as histological lung damage, that correlated with an increase in serum levels of IL-1b.

Evidence- and consensus-based practice guidelines for the diagnosis of irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) presents a significant diagnostic and management challenge for primary care practitioners. Improving the accuracy and timeliness of diagnosis may result in improved quality and efficiency of care.

OBJECTIVE

To systematically appraise the existing diagnostic criteria and combine the evidence with expert opinion to derive evidence- and consensus-based guidelines for a diagnostic approach to patients with suspected IBS.

METHODS

We performed a systematic literature review (January 1966-April 2000) of computerized bibliographic databases. Articles meeting explicit inclusion criteria for diagnostic studies in IBS were subjected to critical appraisal, which formed the basis of guideline statements presented to an expert panel. To develop a diagnostic algorithm, an expert panel of specialists and primary care physicians was used to fill in gaps in the literature. Consensus was developed using a modified Delphi technique.

RESULTS

The systematic literature review identified only 13 published studies regarding the effectiveness of competing diagnostic approaches for IBS, the accuracy of diagnostic tests, and the internal validity of current diagnostic symptom criteria. Few studies met accepted methodological criteria. While symptom criteria have been validated, the utility of endoscopic and other diagnostic interventions remains unknown. An analysis of the literature, combined with consensus from experienced clinicians, resulted in the development of a diagnostic algorithm relevant to primary care that emphasizes a symptom-based diagnostic approach, refers patients with alarm symptoms to subspecialists, and reserves radiographic, endoscopic, and other tests for referral cases. The resulting algorithm highlights the reliance on symptom criteria and comprises a primary module, 3 submodules based on the predominant symptom pattern (constipation, diarrhea, and pain) and severity level, and a subspecialist referral module.

CONCLUSIONS

The dearth of available evidence highlights the need for more rigorous scientific validation to identify the most accurate methods of diagnosing IBS. Until such time, the diagnostic algorithm presented herein could inform decision making for a range of providers caring for primary care patients with abdominal discomfort or pain and altered bowel function suggestive of IBS.

Risk factors associated with mortality in systemic lupus erythematosus. A case-control study in a tertiary care center in Mexico City

OBJECTIVE

To identify the mortality risk factors in a group of Mexican patients with SLE.

METHODS

A case-control autopsy study in a tertiary care center in Mexico, City. Patients with SLE who died during 1958 to 1994 with an autopsy study were selected as cases, and alive patients matched by age (+/- 3 years), decade of SLE onset, and disease duration (+/- 5 years) were defined as controls. Clinical charts were reviewed looking at clinical variables. SLE disease activity was evaluated with the MexSledai index, and SLE disease severity with the Severity Index. Variables were classified as present at any moment during the follow-up and 3 months before death in cases or cut-off date in controls.

STATISTICAL ANALYSIS

matched univariate and multivariate analysis by multiple logistic regression were performed, and the results were presented as odds ratio and 95% confidence intervals (OR, 95%CI).

RESULTS

76 matched pairs of patients were studied. Age, gender, and years offormal education were similar in the cases and controls. Variables associated with mortality three months before death were: lung involvement OR= 15.6, 95%CI (4.8-50.3), p<0.001; severe thrombocytopenia 9.6 (2.9-31.7), p<0.001; heart involvement 5.8 (2.6-13.0), p<0.001; and the severity index (cases 8.8 mu, 2.4 sigma vs controls 3.5, 2.0, respectively) 2.2 (1.5-3.4), p<0.001. Variables associated with mortality detected at any moment before death were kidney involvement 2.16 (1.09-4.29), p<0.02; the steroid therapeutic index 2.3 (1.2-4.5), p<0.001; number of previous admissions 2.4 (1.4-4.3), p<0.001; the MEX-SLEDAI index (cases 21.6 mu 6.3 sigma vs controls 12.6, 5.8), 1.2 (1.1-1.3), p<0.001; and the number of severe infections 14.4 (4.4-46.2), p<0.001. Protective variables were skin involvement 0.1 (0.3-0.6), p<0.001; daily dose of chloroquine (cases 3.9 mu, 24.1 sigma vs controls 39.4, 60.0 mg), p <0.0001 and the time from thefirst SLE symptom to the patient's demise or the cut-off date 0.7(0.6-0.9), p<0.001. Multiple logistic regression showed that the model which best explained mortality consisted of a severity index 2.6 (1.7-3.8), p<0.001; heart disease 6.5 (1.5-28.2), p=0.01, and steroid therapeutic index 3.3 (1.6-6.6), p=0.001.

CONCLUSIONS

An active SLE with multi-organic involvement, steroids and infections were associated with mortality in Mexican patients with lupus attended in a tertiary care center A protective effect of cutaneous disease and chloroquine use was observed.

Defective natural killer and phagocytic activities in chronic obstructive pulmonary disease are restored by glycophosphopeptical (inmunoferón)

We have investigated both modifications in natural (innate) immunity caused by chronic obstructive pulmonary disease (COPD) and the effects of a glycophosphopeptical immunomodulator (Inmunoferón) treatment on COPD-associated immunoalterations. In a double-blinded clinical trial, 60 patients with COPD received glycophosphopeptical or placebo during 90 consecutive days at oral doses of 3 g/d. Fifty-six sex- and age-matched healthy control subjects were included as a reference group for immunologic parameters. Peripheral blood natural killer (PBNK) cell cytotoxic activity and phagocytic activity of peripheral monocytes/macrophages (Mo/Ma) and polymorphonuclear (PMN) cells were assessed at baseline and then again at the end of treatments. We found both PBNK activity and phagocytic activity to be significantly decreased in patients with COPD compared with levels in healthy volunteers. The treatment with glycophosphopeptical provoked significant stimulatory effects on PBNK cytotoxic activity. This stimulation was not mediated by an increase in CD3(-)CD56(+) NK cells. Further, glycophosphopeptical significantly increased the percentage of monocytes and PMNs that phagocytize Escherichia coli in vitro, as well as increased phagocytic indices. We conclude that peripheral blood cells of patients with COPD show clear defects in natural immunity that are partially rescued by glycophosphopeptical.

Left sided heartport approach for combined mitral valve and coronary bypass surgery

BACKGROUND

To explore the possibility of achieving adequate exposure of the mitral valve (MV) and the entire coronary anatomy using a limited (Port-Access) left lateral thoracotomy incision.

METHODS

Using this incision, four patients underwent a single bypass to the left anterior descending, combined with MV repair (1), MV replacement (2), and left atrial (LA) myxoma excision (1). This approach required single lung ventilation, femoral venous cannulation, and cannulation of the femoral artery or thoracic aorta. Exposure of the MV was achieved through a LA incision parallel to the atrio-ventricular groove, extending into the pulmonary vein or behind the pulmonary artery as necessary.

RESULTS

Excellent exposure of the MV and coronary anatomy was achieved in all patients. There were no surgical complications and all were discharged home within one week.

CONCLUSION

Left-sided Port-Access is a valid technique particularly suitable for combined primary MV and coronary bypass surgery. It does not allow exposure of the tricuspid or aortic valve, however, and is not recommended in repeat MV surgery due to the fragility of the LA appendage in such cases.

Variability of sperm specific histones in sea urchins

The variability of sperm histones was compared in two species of sea urchin. Whole sperm specific histones (SpH), were isolated from Tetrapygus niger (Arbacoida) and Parechinus angulosus (Echinoida). Individual histones were purified by chromatography on BioGel P-60 followed by reverse high pressure liquid chromatography (HPLC). The heterogeneity of each major histone type from T. niger was established from their HPLC elution patterns and further confirmed by electrophoresis in polyacrylamide gels containing 6 mM Triton X-100 combined with a transverse urea gradient (0--8 M). In T. niger, as well as in P. angulosus, a single form of SpH1 and SpH2A were found. In contrast, SpH2B was found to be heterogeneous, but represented by one major form in both species. The relatedness between both sets of histones was determined by establishing their immunological cross-reactivity. In this context, polyclonal antibodies elicited against T. niger sperm histones were assayed against individual histones from P. angulosus. From the results obtained, it emerged that histone SpH2A was the more closely related protein between these two species, followed by histone SpH1. In contrast, histone SpH2B was found to be only moderately related. These results confirm that SpH2A did not co-evolve with SpH2B, as was predicted for most species.

Clinical effect of a Mexican sanguinaria extract (Polygonum aviculare L.) on gingivitis

It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. A number of chemical agents have been evaluated over the years with regard to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of a natural Mexican Sanguinaria extract (Polygonum aviculare L.) against gingivitis, was assessed in 60 male dentistry students between the ages of 18 and 25 years. Over a period of 2 weeks, these students used the Sanguinaria extract (1 mg/ml) in oral rinse twice daily as a unique oral health measurement (no tooth-brushing was allowed). The O'Leary Plaque Index and the Löe and Silness Gingivitis Index were recorded at baseline (day 0) in all the subjects. Also, a complete prophylaxis was performed after both indices were obtained. The antibacterial and antiinflammatory effects of the extract were evaluated on days 7, 11 and 14. The results showed that the Mexican Sanguinaria extract in oral rinse significantly decreased gingivitis from day 0 (-x=1. 056) to day 14 (-x=1.011) (P</=0.05). In contrast, a significant increase in dental plaque was observed from day 0 (-x=91.38) to day 14 (-x=98.69) (P</=0.05); however, the consistency of this plaque permitted its mechanical flushing easily. From this study, it is concluded that the Mexican Sanguinaria extract in oral rinse can be employed supportively in the therapy of gingivitis.

Fetoprotectivity of the flavanolignan compound siliphos against ethanol-induced toxicity

Of the three flavanolignans that are found in silymarin (Silybum marianum [L.] Gaertn.), silybin is thought to be the primary therapeutic constituent. To test the capacity of silybin to protect the rat fetus from toxic effects of maternally ingested EtOH we did the following: Adult female rats were assigned to one of four groups; EtOH, EtOH/silybin, pair-fed control, and chow fed control. Silybin was orally administered as Siliphos(R), which is one part silybin to two parts phosphatidylcholine. All groups except the chow-fed control were maintained on a liquid diet throughout pregnancy. On day 21 of pregnancy the rats were killed and the fetuses removed. Gamma glutamyl transpeptidase (GGTP) activity and glutathione (GSH) levels were determined for liver and brain tissue for both the fetuses and the dams. Maternal and fetal GGTP activity in the EtOH rats was significantly higher than that of pair-fed controls, whereas the GGTP activity observed in the Siliphos(R)/EtOH rats was not elevated. Fetal mortality rates in the EtOH rats significantly exceeded those of all three other groups.

Fulminant EBV(+) T-cell lymphoproliferative disorder following acute/chronic EBV infection: a distinct clinicopathologic syndrome

This study describes the clinicopathologic features of 5 patients who developed a fulminant Epstein-Barr virus (EBV)-positive clonal T-cell lymphoproliferative disorder (LPD) after acute EBV infection. One additional patient developed a similar disorder in the setting of long-standing chronic active EBV infection. Detailed immunophenotyping, in situ hybridization for EBV early RNA-1 (EBER1) and polymerase chain reaction (PCR) analyses for immunoglobulin (Ig) heavy chain and T-cell receptor (TCR)-gamma gene rearrangements were performed on paraffin-embedded tissue from all patients. In addition, EBV strain typing and detection of the characteristic 30-bp deletion of the latent membrane protein-1 (LMP-1) gene were performed by PCR. Controls included 8 cases of uncomplicated infectious mononucleosis (IM). Patients included 4 males and 2 females with a median age of 18 years (2-37 years). Three patients were Mexican, 2 were white, and 1 was of Asian descent. All presented with fever, hepatosplenomegaly, and pancytopenia; 5 were previously healthy, but had a clinical history of a recent viral-like upper respiratory illness (1 week to 2 months), and 1 patient had documented chronic active EBV infection for 7 years. Serologic data for EBV were incomplete but titers were either negative or only modestly elevated in 3 cases. In 1 case serology was consistent with severe chronic active EBV infection. In the remaining 2 cases serologic studies were not performed. All patients died within 7 days to 8 months of presentation with T-cell LPD. On histologic examination, the liver and spleen showed prominent sinusoidal and portal lymphoid infiltrates of CD3(+), beta F1(+), EBER1(+) T cells lacking significant cytologic atypia. Two cases were CD4(+), 2 cases were CD8(+), and 2 cases had admixed CD4(+) and CD8(+) cells without clear subset predominance. All were TIA-1(+), CD56(-). Only rare B cells were noted. Marked erythrophagocytosis was present. Molecular analysis revealed identical T-cell clones in 2 or more sites (liver, spleen, lymph node) in 5 cases. All patients carried type A EBV; 4 cases had wild-type EBV-LMP, and 2 showed the 30-bp deletion. This fulminant T-cell LPD after acute/chronic EBV infection is characterized by hepatosplenomegaly, often without significant lymphadenopathy, fever, liver failure, pancytopenia, and erythrophagocytosis indicative of a hemophagocytic syndrome. EBV serology may be misleading, with lack of elevated titers. The presence of an EBER1(+) T-cell infiltrate with scant B cells should alert one to this diagnosis. Although cytologic atypia is minimal, studies for T-cell clonality confirm the diagnosis. (Blood. 2000;96:443-451)

Liposomal amphotericin B and amphotericin B-deoxycholate show different immunoregulatory effects on human peripheral blood mononuclear cells

Conventional preparations of amphotericin B (AmB) at established therapeutic doses are known to increase nonspecific immune responses. It remains to be established whether higher doses of the less toxic liposomal preparation of AmB maintains a beneficial effect on the immune response to fungal infections. Examination of the effect of treatment of human peripheral blood mononuclear cells from healthy subjects with various doses of both liposomal AmB (L-AmB) and deoxycholate AmB (d-AmB) on proliferation, cell viability, and percentage of apoptosis demonstrated that, although both L-AmB and d-AmB at low doses significantly increased nonspecific proliferative responses, L-AmB, but not d-AmB, treatment maintained this beneficial effect at higher doses. High doses of d-AmB, but not L-AmB, resulted in significantly decreased cell viability and increased apoptosis. This study provides further evidence in healthy human subjects for choosing L-AmB over conventional preparations in the clinical treatment of fungal infections requiring systemic high-dose treatment with AmB.

A mutation in the 5' non-high mobility group box region of the SRY gene in patients with Turner syndrome and Y mosaicism

In Ullrich-Turner syndrome (UTS) patients, the presence of a Y-chromosome or Y-derived material has been documented in frequencies ranging from 4-61%. Mutations of SRY (testis-determining gene) constitute the cause of XY sex reversal in approximately 10-15% of females with pure gonadal dysgenesis. Most of these mutations have been described in the HMG (high mobility group) box of the gene, which is the region responsible for DNA binding and bending; however, various mutations outside the HMG box have been reported. We carried out molecular studies of the SRY gene in three patients with a UTS phenotype and bilateral streaks; two presented a 45,X/46,XY mosaic, and the third a Y marker chromosome. In two patients a missense mutation, S18N, was identified in the 5' non-HMG box region in DNA from blood and both streaks; this mutation was not identified in 75 normal males. Sequencing of the DNA region of interest was normal in the father and older brother of patient 1, demonstrating that in this patient the mutation was de novo. A previous report of a 46,XY patient with partial gonadal dysgenesis who presented the same mutation as our patients indicates the probable existence of a hot spot in this region of the SRY gene and strengthens the possibility that all gonadal dysgeneses constitute part of a spectrum of the same disorder. It also demonstrates that a single genetic abnormality can result in a wide range of phenotypic expression.

A new method for the simultaneous analysis of growth and death of immunophenotypically defined cells in culture

BACKGROUND

Internal standards have been used in flow cytometry methods to enumerate lymphoid subsets and hemopoietic progenitor cells ex vivo. However, the currently available methods cannot be readily applied to the analysis of cultured cells because of the frequent occurrence of cell death during in vitro assays.

METHODS

This paper reports a new method for the enumeration of both viable and nonviable cells in culture. Cells were counted with the aid of an internal reference standard of microbeads, and live versus dead cell discrimination was performed using 7-amino-actinomycin D which allows the double staining of surface antigens.

RESULTS

The method is more precise, accurate and sensitive than either conventional light microscopy-based or automated cell counting. Additionally, it may be used to accurately measure the number of apoptotic cells in a culture.

RESULTS

Through the enumeration of surviving cells it is demonstrated that, when applied to the study of mitogen-activated T lymphocytes, current flow cytometry techniques (which do not use internal standards) for the study of the viability and apoptosis overestimate the fraction of viable cells and underestimate both the fraction of dead and apoptotic cells.

CONCLUSIONS

The new method overcomes these limitations and is of use in the in vitro study of cell growth and apoptosis.

Chicken anemia virus and fowl adenoviruses: association to induce the inclusion body hepatitis/ hydropericardium syndrome

The effects of a simultaneous and/or a subsequent coinfection with chicken anemia virus (CAV) isolate 10343 and fowl adenovirus (FAV) isolate 341 in specific-pathogen-free light chickens were evaluated. The simultaneous coinfection was conducted by the intramuscular route, whereas the subsequent coinfection trial considered FAVs administered orally. In trial 1, 20-day-old chickens simultaneously coinfected with CAV (10343) and FAV (341) intramuscularly (i.m.) showed 55% mortality and characteristic signs and lesions of inclusion body hepatitis/hydropericardium (IBH/HPS). In contrast, birds singly infected with FAV i.m. showed 10% mortality due to IBH/HPS. Trial 2 showed that birds receiving FAV 341 orally at day 7 post-CAV intramuscular infection (group A) developed a mild form of IBH/HPS with presence of inclusion bodies (INIBs) in 60% of the group and virus-neutralizing antibodies against FAV 341. Group B (FAV orally 14 days after CAV) showed significant decreased weight gain, nonspecific microscopic lesions in the liver, spleen, bursa, and thymus, and an antibody response against FAV 341. However, no INIBs could be detected in the hepatocytes of these chickens. Group C (FAV orally 35 days after CAV) showed nonspecific histopathologic changes in the liver and no antibody response to FAV. The oral single infection with FAV isolate 341 induced neither mortality nor macroscopic lesions of IBH/HPS in the birds. The present results corroborate previous reports on pathogenicity of Chilean FAV isolates, which suggest that synergism with other viruses or prior immunosuppression is necessary to produce IBH/HPS in chickens. These results also suggest that the susceptibility of chickens to FAV oral infection resulting in IBH/HPS varies throughout the course of CAV infection.

Contamination of peritoneal dialysis fluid by filamentous fungi

Peritonitis is a frequent complication in peritoneal dialysis. It may be caused by contamination of the dialysis tubing or by extension of the catheter exit site. Gram-positive bacteria are the most common organism, accounting for 60% of all documented cases of continuous ambulatorial peritonitis dialysis. Fungi are isolated from to 1-15% of cases. Forty-nine out of 490 bottles containing fluid for peritoneal dialysis were randomly selected for microbiological analysis in São Paulo, Brazil. In this report the contamination of peritoneal dialysis fluid by Chaetomium globosum and Chrysonilia sitophila is reported.

Oculocardiac reflex in sedated patients having laser in situ keratomileusis

PURPOSE

To eliminate stress as a variable in assessing the frequency of the oculocardiac reflex during laser in situ keratomileusis (LASIK).

SETTING

Merida Ophthalmological Hospital and Oftalmedica, Mexico City, Mexico.

METHODS

A pulse oximeter registered the heart rate of 30 sedated patients having LASIK. Sedation was accomplished with a combination of midazolam and fentanyl. The heart rate was noted before and during suction. The results in 1 eye of each patient were recorded. Oculocardiac reflex was defined as a decrease of 10% or more of the basal heart rate.

RESULTS

Fourteen patients (46.7%) had a 10% or more decrease in heart rate when suction was applied. Ten of the 14 had a decrease in heart rate between 10% and 19%, 3 between 20% and 29%, and 1 of more than 30%. Two patients (6.6%) had an increase in the basal heart rate of more than 10%.

CONCLUSIONS

The findings suggest that the oculocardiac reflex occurs more frequently in sedated patients than in nonsedated patients.