A Taenia crassiceps factor induces apoptosis of spleen CD4+T cells and TFG-ß and Foxp3 gene expression in mice.

This study was undertaken to determine whether a parasite substance produces structural pathology in the mouse spleen. A low-molecular-weight Taenia crassiceps metacestode factor (MF) isolated from the peritoneal fluid of female mice infected with T. crassiceps metacestodes induced pathological and immunological changes in mouse spleen cells in vivo. Electron microscopy and confocal microscopy revealed severe changes in the spleen histoarchitecture of T. crassiceps-infected and MF-treated mice. Apoptotic degenerated spleen cells were observed in the white and red pulps and were more conspicuous in the white pulp of the spleen from the T. crassiceps-infected mice than in that of the MF-treated mice. Flow cytometry analysis revealed that the numbers of spleen CD4+T cells were significantly lower in both experimental groups than in control mice. The ex vivo expression of transforming growth factor (TGF)-ß and factor Foxp3 were significantly higher in splenocytes of the experimental mice than the basal expression observed in the control cells. These findings may have potential applications for a better understanding of the host-parasite relationship in human neurocysticercosis.

Insulin resistance, low-grade inflammation and type 1 diabetes mellitus.

To assess the relationships between insulin resistance and low-grade inflammation in subjects with type 1 diabetes mellitus (T1DM) who do not have clinical macrovascular complications. A total of 120 subjects diagnosed with T1DM 14 years before were evaluated for the following: (1) sex, age, body mass index, waist-to-hip ratio (WHR), blood pressure, smoking, alcohol intake, insulin dose, HbA1c and lipid profile; (2) microvascular complications; (3) plasma concentrations of soluble fractions of tumour necrosis factor-α receptors type 1 and 2, interleukin-6, adiponectin, leptin and high-sensitivity C-reactive protein (hs-CRP); and (4) insulin resistance (estimation of the glucose disposal rate-eGDR). Those subjects with an eGDR below the median of the same sex group were classified as insulin resistant and the others as insulin sensitive. Insulin-resistant men, compared to the insulin-sensitive, had higher WHR (0.89 ± 0.08 vs. 0.83 ± 0.05; P < 0.01), higher systolic [121 (118-125) vs. 114 (108-120) mmHg; P = 0.01] and diastolic [73 (66-80) vs. 67 (70-73) mmHg; P = 0.02] blood pressures, higher HbA1c values [8.7 (8.1-9.9) vs. 7.5 (7.2-8.0) %; P < 0.01] and higher hs-CRP concentrations [1.16 (0.61-3.20) vs. 0.49 (0.31-0.82) mg/dl; P = 0.01], but no other significant differences between groups were found. Insulin-resistant women had higher WHR and HbA1c values, compared to the insulin-sensitive, but they did not have any other differences. In men, hs-CRP correlated significantly with WHR and HbA1c (r = 0.363; P = 0.016 and r = 0.317; P = 0.036, respectively), after adjusting for age, alcohol intake, smoking and microvascular complications. Insulin-resistant men with T1DM have an increase in plasma concentrations of hs-CRP. Central obesity and HbA1c are its main determinants.

Comparativa entre los diversos tratamientos de la hiperglucemia: estrategias para minimizar la ganancia ponderal en la diabetes tipo 2 / Comparison between several antihyperglycemic treatments: strategies to minimize weight gain in type 2 diabetes

La pérdida de peso es fundamental para el tratamiento de los pacientes condiabetes tipo 2, dado que se asocia a disminución de la resistencia a la insulinay a mejoría del control metabólico. Sin embargo, los fármacos disponibles parael tratamiento de la hiperglucemia tienen un efecto variable sobre el peso: losanálogos del GLP-1 lo disminuyen; el tratamiento con sulfonilureas, meglitinidas,tiazolidindionas e insulina se asocia a ganancia ponderal, mientras que lametformina, los inhibidores de la enzima dipeptidilpeptidasa IV y los inhibidoresde la alfaglucosidasa tienen un efecto neutral en el peso. Al mismo tiempo, lamayoría de guías de práctica clínica para el tratamiento de la hiperglucemiaproponen escaladas terapéuticas sin tener en cuenta la ganancia ponderal. Elobjetivo de este seminario es revisar el efecto sobre el peso de los diversostratamientos para la hiperglucemia y proponer estrategias terapéuticas paraminimizar la ganancia ponderal asociada al tratamiento de la diabetes tipo 2(AU)

Weight loss is important for treatment of type 2 diabetic patients, because it isassociated with a decrease in insulinresistance and with the improvement ofmetabolic control. However, the available antihyperglycemic treatments mayhave variable effects on body weight. GLP-1 analogues induce weight loss.Sulfonylureas, meglitinides, thiazolidinediones and insulin are associated withweight gain, whereas metformin, dipeptidyl peptidase 4 inhibitors and alphaglucosidaseinhibitors are weight neutral. Concomitantly, most of the clinicalpractice guidelines for diabetes treatment propose therapeutical steps independentlyof their effect on weight. The aim of this seminary is to review theeffect of different antihyperglycemic treatments on weight and propose strategiesto minimize weight gain in type 2 diabetes(AU)

Plasma visfatin concentrations increase in both hyper and hypothyroid subjects after normalization of thyroid function and are not related to insulin resistance, anthropometric or inflammatory parameters.

OBJECTIVE: The objective of this study was to evaluate plasma visfatin levels in thyroid dysfunction and its relationship with inflammatory, anthropometric and insulin resistance parameters. DESIGN AND PATIENTS: Twenty-four hyperthyroid and 27 hypothyroid patients were studied before and after treatment. Forty-five euthyroid subjects were used as control group. MEASUREMENTS: Fasting plasma visfatin, IL-6, C reactive protein, adiponectin, thyroid hormones, waist-to-hip ratio, BMI, percentage of body fat and homeostasis model insulin resistance index (HOMA-IR) were measured. RESULTS: Hyperthyroid patients showed increased insulin resistance, IL-6 and visfatin levels compared with controls (3.21 +/- 3.0 vs. 1.67 +/- 0.75, P = 0.022; 3.35 +/- 0.41 vs. 2.10 +/- 0.25 pg/ml, P = 0.016; and 37.4 +/- 5.81 vs. 23.79 +/- 4.2 ng/ml, P = 0.061 respectively). After normalization of thyroid function, IL-6 levels and HOMA-IR decreased (2.35 +/- 0.37 vs. 2.10 +/- 0.25 pg/ml, P = 0.045 and 3.21 +/- 0.60 vs. 2.28 +/- 0.38, P = 0.032 respectively), while body weight, adiposity and visfatin levels increased (26.1 +/- 1.2 vs. 26.7 +/- 1.2 kg/m(2), P = 0.049; 30.9 +/- 1.6 vs. 32.2 +/- 1.6%, P = 0.007; and 37.4 +/- 5.81 vs. 63.13 +/- 8.72 ng/ml, P = 0.047 respectively). C reactive protein and adiponectin levels were similar to those of the control group. Hypothyroid patients showed high visfatin levels (40.59 +/- 3.07 vs. 29.34 +/- 4.9 ng/ml, P = 0.049) that increased after treatment (81.4 +/- 9.2 ng/ml, P = 0.001) without changes in anthropometric or insulin resistance parameters. C reactive protein, IL-6 and adiponectin levels were similar to those of the control group. No correlations between visfatin and any analysed parameter were found in either hyper- or hypothyroidism. CONCLUSION: Visfatin exhibits a marked increase after normalization of thyroid function in both hyper and hypothyroid patients. We suggest that visfatin may play a role in the hormone stabilization process independent of anthropometric, inflammatory or insulin resistance variables.

[Usefulness of computerized tomography and bronchoscopy in patients with hemoptysis. Analysis of 482 cases]. / Utilidad de la tomografía computarizada y la broncoscopia en los pacientes con hemoptisis. Análisis de 482 casos.

OBJECTIVE: We have examined the computed chest tomography (CT) and bronchoscopy utility in diagnosis and accurately identifying the sites of pulmonary bleeding in patients with hemoptysis. METHODS: We prospectively reviewed the etiology and the site of bleeding of 482 patients with hemoptysis who had undergone bronchoscopy and CT when we suspected a carcinoma, bronchiectasis or the type of bleeding. We analyzed the age, sex, history of tobacco, bleeding, chest radiography, chest computed tomography and bronchoscopy. RESULTS: 62 years (DS 13.6), 84.4% males, 80% smokers and a volume of bleeding of 42.5 ml/day (DS 89) for 15 days (DS 25). Lung cancer was identified in 43%, bronchiectasis in 20%, chronic obstructive lung disease in 14%, pneumonia 8% and an unknown etiology in only 3%. Bronchoscopy located the site of bleeding in 77% and CT in 83%. When we examine only the lung carcinomas, the chest radiography was normal in 11% and the bronchoscopy was diagnostic in 87%, including 6 cases with a normal CT. Simultaneously chest CT or radiography and bronchoscopy detected all the lung cancers. When the chest radiography was inespecific (32%), CT was diagnostic in 43% and bronchoscopy in 14% (p < 0.001) or localized the site of bleeding in 52% with the CT or 23% with the bronchoscopy (< 0.001). CONCLUSIONS: We concluded that bronchoscopy and CT were useful and complementary in etiologic diagnosis and to localize the site of bleeding in patients with hemoptysis. The bronchoscopy was preferable in patients with a lung cancer and the CT when we studied all the etiologies or the patients without a lung cancer, especially when the radiography was normal. When we simultaneously used a CT or a radiography and the bronchoscopy, all the lung cancers were detected.

Utilidad de la tomografía computarizada y la broncoscopia en los pacientes con hemoptisis / Computed chest tomography and bronchoscopy utility in patients with hemoptysis. Analysis of 482 cases

Objetivo: Analizar la utilidad de la fibrobroncoscopia (FB) y la tomografía computarizada (TC) en el diagnóstico etiológico y la localización del sangrado en los pacientes con hemoptisis. Métodos: Estudio descriptivo y prospectivo de la etiología o la localización del sangrado en 482 pacientes con hemoptisis a los que se les realizó una FB y una TC por la sospecha de una neoplasia, bronquiectasias o las características del sangrado. Se valoraron la edad, sexo, tabaquismo, características de la hemoptisis y los resultados de la radiografía de tórax, FB y TC.R e s u l t a d o s : Edad 62 años (DE 13,6), 84,4 por ciento varones, 80 por ciento fumadores con un volumen de sangrado de 42,5 ml/día (DE 89) durante 15 días (DE 25). Las causas más frecuentes incluyeron las neoplasias (43 por ciento), bronquiectasias (20 por ciento), bronquitis crónica (14 por ciento) y neumonías (8 por ciento) junto a un 3 por ciento de formas idiopáticas. La FB localizó el sangrado en el 77 por ciento y la TC identificó alteraciones compatibles con el posible origen del sangrado en el 83 por ciento. En las neoplasias, la radiografía fue normal en el 11 por ciento y en el 87 por ciento la FB aportó el diagnóstico, mientras en 6 casos la TC fue normal. En ningún caso, la TC o la radiografía y la FB fueron normales simultánemente en las neoplasias. Cuando la radiografía era inespecífica (32 por ciento), la TC aportó el diagnóstico etiológico en el 43 por ciento y la FB en el 14 por ciento (p<0,001) o localizó el sangrado en el 52 por ciento la TC y el 23 por ciento la FB (p<0,001).C o n c l u s i o n e s : La FB y la TC fueron útiles y complementarias en el diagnóstico etiológico o localización del sangrado de nuestros pacientes. La FB fue la exploración más útil en los pacientes con una neoplasia y la TC de forma global o en los pacientes sin una neoplasia, especialmente si la radiografía era normal o inespecífica. El uso simultáneo de la TC o la radiografía y la FB evitó que ningún caso de neoplasia pasara desapercibida (AU)

Objective: We have examined the computed chest tomography (CT) and bronchoscopy utility in diagnosis and accurately identifying the sites of pulmonary bleeding in patients with hemoptysis. Methods: We prospectively reviewed the etiology and the site of bleeding of 482 patients with hemoptysis who had undergone bronchoscopy and CT when we suspected a carcinoma, bronchiectasis or the type of bleeding. We analyzed the age, sex, history of tobacco, bleeding, chest radiography, chest computed tomography and bronchoscopy. Results: 62 years (DS 13.6), 84.4% males, 80% smokers and a volume of bleeding of 42,5 ml/day (DS 89) for 15 days (DS 25). Lung cancer was identified in 43%, bronchiectasis in 20%, chronic obstructive lung disease in 14%, pneumonia 8% and an unknown etiology in only 3%. Bronchoscopy located the site of bleeding in 77% and CT in 83%. When we examine only the lung carcinomas, the chest radiography was normal in 11% and the bronchoscopy was diagnostic in 87%, including 6 cases with a normal CT. imultaneously chest CT or radiography and bronchoscopy detected all the lung cancers. When the chest radiography was inespecific (32%), CT was diagnostic in 43% and bronchoscopy in 14% (p<0.001) or localized the site of bleeding in 52%with the CT or 23% with the bronchoscopy (<0.001). Conclusions: We concluded that bronchoscopy and CT were useful and complementary in etiologic diagnosis and to localize the site of bleeding in patients with hemoptysis. The bronchoscopy was preferable in patients with a lung cancer and the CT or a radiography and the bronchosopy, all the lung cancers were detected (AU)

Postpartum weight loss and infant feeding.

BACKGROUND: Women are often advised that lactation accelerates loss of the excess weight gained during pregnancy, but the evidence underlying this advice is sparse and conflicting. To help fill this gap, we assessed differences in the rate of postpartum weight loss in the first 9 months postpartum according to method of infant feeding. METHODS: Two hundred thirty-six women attending two public health clinics in Montreal were weighed in one to four routine infant immunization visits up to the 9th postpartum month. After each weighing, we administered a telephone questionnaire assessing the method of infant feeding (predominantly breast-feeding, mixed-feeding, or predominantly bottle-feeding) and potential confounders. Data were analyzed using unbalanced multivariate repeated measures linear regression. RESULTS: Infant feeding was not associated with statistically significant differences in the rate of weight loss. Gestational weight gain, postpartum smoking, and maternal birthplace were important predictors of postpartum weight change. CONCLUSION: Although our results cannot exclude an effect of more exclusive or more prolonged breast-feeding, breast-feeding as commonly practiced does not appear to influence the rate of postpartum weight loss. This information should be useful in counseling new or prospective mothers and in avoiding unrealistic expectations.

Materiales de sutura: principios que determinan su escogencia / Suture materials, how to choose

Los materiales de sutura, antiguos como la humanidad, han evolucionado desde las agujas oseas utilizadas en la prehistoria hasta nuestros días. Aunque no se ha logrado obtener la sutura ideal, existe una variada gama de ellas; su indicacion es precisa y su efectividad depende de varies factores tales como su manejo dentro del quirofano, la experiencia y el buen juicio del cirujano. Es potestad del cirujano escoger el tipo de material de sutura que conviene utilizar en una cirugia determinada; en muchas ocasiones se observa que esta escogencia depende más de la costumbre que de patrones establecidos; podriamos decir que el cirujano es ®producto de su adiestramiento¼, siendo la escuela en donde se formo y el tutor más cercano a el, quienes ejercen una influencia duradera que marcará su preferencia en materiales de sutura. Se realiza una revision y análisis de los aspectos más preponderantes de este interesante tema, brindando una guía de gran ayuda al medico residente del area quirurgica, al cirujano especialista y al personal que de una u otra forma tiene relacion con esta disciplina.

Small-cell lung cancer in the elderly--is age of patient a relevant factor?

Different management procedures for diagnosis and treatment of small-cell lung cancer (SCLC) and other tumours in the elderly have been reported, but there is a lack of data from a communal hospital perspective. Information on clinical parameters such as weight loss, co-morbidity, performance status and investigative procedures for staging of disease and inclusion in clinical trials was recorded for patients in the province of Albacete (Spain). Patients' ages were categorized in two groups: under 70 years and 70 years or more, and a comparison of treatment variables, toxicities, response and time to event measures was carried out. Ninety-five patients were referred to our Unit for treatment. Of these patients, 62% were under 70 years of age and 38% were in the older age category. Clinical variables and staging procedures did not differ between groups. Trial assignment showed a bias in favour of younger patients (11 vs. 1, p = 0.02). No differences in the number of patients without treatment were found, but the older group presented fewer cases of optimal (> or = 4 cycles) therapy, less chemotherapy delivery (smaller mean total doses of cisplatin and etoposide) and smaller mean total dose of radiotherapy (57/45 Gy). The response to treatment (46%/50%) toxicity registered and overall survival did not differ between age categories. Age does not seem to be a relevant prognostic factor in this disease. Carefully calculated dose reductions for chemotherapy in elderly patients based on initial performance status and/or toxicity during treatment may be a useful policy without detrimental implications on outcome.

Cirugía del aneurisma de la aorta abdominal: bases fisiológicas y monitoría. Experiencia en el Hospital Universitario de Cartagena / Surgery of abdominal aortic aneurysm: physiological bases and monitoring. Experience at Hospital Universitario de Cartagena

El tratamiento adecuado del aneurisma de la aorta abdominal, está encaminado a la reseccion y colocacion de protesis, cirugia que actualmente se encuentra reglada y estandarizada; es sencilla y directa y arroja tasas de morbimortalidad minimas en la mayoria de los centros hospitalarios. Lo que mas ha progresado en esta entidad es el diagnostico, la fisiopatologia y el manejo hemodinámico durante el pre, trans y postoperatorio de la misma. En este trabajo se presenta la experiencia con el tipo de cirugia mencionado, practicado en el E.S.E. Hospital Universitario de Cartagena, durante el periodo comprendido entre marzo de 1988 y febrero de 7998. Se operaron 39 pacientes, 31(76.6 por ciento) hombres y 8(23.4 por ciento) mujeres; las edades oscilaron entre 52 y 79 años, con un promedio de 65.3 años y una desviacion estándar de 7.8. El motivo de consulta mas frecuente fue el dolor abdominal, seguido por sensacion de masa abdominal. El metodo diagnostico definitivo mas frecuente fue la ecografia abdominal en 55.3 por ciento, seguido por la tomografia axial computarizada (TAC) del abdomen, en 44.7 por ciento. Se utilizo cateter de Swan-Ganz. en 32 pacientes (84.2 por ciento); las patologias asociadas en su orden fueron, la cardiopatia en 15 casos (38.5 por ciento) y la hipertension arterial en 11 pacientes (28.2 por ciento). Se uso el injerto en pantalon en 31 pacientes (66 por ciento), y en 8 (17 por ciento) como injerto tubular. La mortalidad en esta serie fue de 1 paciente (2.1 por ciento). Se realiza una extensa revision de la patologia y se hace enfasis en los aspectos etiologicos, diagnosticos, fisiopatologicos, manejo hemodinámico y control durante el pre, trans y postoperatorio, con base en la experiencia acumulada en este tipo de cirugia en nuestro Hospital.

[Impact of gender and influence of tobacco on the etiology of patients with hemoptysis]. / Importancia del sexo e influencia del tabaco en la etiología de los pacientes con hemoptisis.

OBJECTIVE: To evaluate the importance of the sex and the influence of tobacco on the etiology of patients with hemoptysis. METHODS: We analyzed and compared the etiology of 394 consecutive patients with hemoptysis, divided in two groups: I (males) and II (females), and stratified in relation to tobacco. RESULTS: 305 males (77.4%) and 89 females (p < 0.0001). Lung cancer was more frequent in both groups (26.9%), especially squamous cell carcinoma, but nonmalignant etiologies were more common when we considered all globally (73.1%), including chronic obstructive lung disease (COPD) (14.9%) or bronchiectasis (20.4%) as the more frequent diseases, and 14.2% of unknown etiology (5.2% if we excluded bronchitis or lung infections). Lung tuberculosis was decreased (1.5%) in relation to a increased frequency of its sequelaes or residual lesions (10%). The initial increased frequency of lung cancers or COPD in males and bronchiectasis or heart diseases in females disappeared after the stratification and elimination of the tobacco effect. CONCLUSIONS: Hemoptysis was more frequent in males and nonmalignant etiologies were more common in both groups, with similar rates as in previous literature and a low number of cases with a unknown etiology associated to a protocolized study and the increased use of diagnostic procedures. In our study, the etiology of patients with hemoptysis was sex independent, to show that the susceptibility to tobacco illness was similar in both sexes.

Importancia del sexo e influencia del tabaco en la etiologíade los pacientes con hemoptisis / Impact of the sex and influence of tobacco on the etiology of patients with hemoptysis

Objetivo: Analizar la importancia del sexo en la etiología de los pacientes con hemoptisis y la influencia del tabaco sobre la misma. Métodos: Estudiar y comparar la etiología de 394 pacientes consecutivos con hemoptisis, divididos en dos grupos: I (varones) y II (mujeres), posteriormente estratificados en relación al tabaquismo. Resultados: 305 varones (77,4%) y 89 mujeres (p<0,0001). La etiología más frecuente fue la neoplasia pulmonar (26,9%), la mayoría por carcinoma epidermoide, aunque globalmente predominaban las etiologías no malignas (73,1%), y de entre ellas la bronquitis crónica (14,9%) y las bronquiectasias (20,4%), con un 14,2 porciento de causa desconocida (5,2%de las benignas si excluimos las bronquitis o infecciones respiratorias), destacando una disminución de la etiología tuberculosa (1,5%) a diferencia de sus secuelas o lesiones residuales (10%). Se observó un predominio inicial de bronquitis crónica y neoplasias en hombres, y de bronquiectasias y cardiopatía en mujeres que desapareció tras la estratificación y eliminación del efecto del tabaco. Conclusiones: La hemoptisis fue más frecuente en varones y su etiología no neoplásica fue la que predominó de forma global y en ambos sexos, con unas frecuencias similares a las descritas en la literatura y con un bajo porcentaje de etiología desconocida al realizar un estudio protocolizado y un amplio número de exploraciones complementarias. La etiología de la hemoptisis fue independiente del sexo demostrando una susceptibilidad similar para las enfermedades relacionadas o no con el tabaco en nuestros pacientes (AU)

Spontaneous shift of an HSV type 1 productive, persistently infected macrophage-like culture to a non-productive culture.

A herpes simplex virus type 1 (HSV1) productive, persistently infected murine macrophage-like culture was obtained by infection at low multiplicity (0.001). Persistent cultures were characterized by spontaneously ceasing to produce infectious viruses after initial HSV1 production. A similar pattern of virus production was observed in cultures obtained by reinfection of the persistent macrophages with the original virus. Nonetheless, in persistent and reinfected cultures (17/18) which did not produce infectious viruses, viral proteins were detected by immunoblot, although their molecular weight, number and pattern differed among the cultures.

Reinfection-induced increase of rubella persistently infected cells in a macrophage-like cell line.

The establishment and relevant characteristics of a long-term rubella persistent infected immortalised murine macrophage culture with a high proportion of persistent infected cells over uninfected is described. The high proportion of persistent infected macrophages was obtained through reinfection with the original virus. Prior to reinfection, 35-50% of the cells expressed viral antigen, 0.05-1.5% produced infective virus and extra-cellular virus was continuously produced with infective titers cyclically fluctuating between 10(2) and 10(7) TCID50/ml. After reinfection, the macrophages which expressed viral antigen and produced infective virus had increased to 75-90% and 30-45% respectively and extracellular virus was continuously produced with stable titer between 10(2)-10(3) TCID50/ml. Furthermore, in the reinfected culture no significant variation was observed in the percentage of cells expressing antigen, producing virus and in the titer of extracellular virus for longer than a year of passages.

Quantitative determination and visualization of herpes simplex virus type 1 antigen, free and cell-bound by ELISA.

A method of quantifying and visualizing herpes simplex virus type 1 antigen by indirect enzyme-linked immunosorbent assay (ELISA) is described. This assay is simplified by the use of polyclonal serum and can be applied to the quantification of free antigen as well cell-bound. Moreover, cell viral antigen can be visualized. Antigen sources were viral suspensions, infected cells and proteins extracted from infected cells. The assay was specific and its sensitivity was dependent on the antigen source. The technique was regarded as specific within a range showing a direct correlation (r > 0.8) between the concentration of the antigen and the net absorbance value (the difference of the absorbance obtained with the viral antigen minus the control antigen). The technique has advantages over other ELISA procedures: does not require monoclonal antibodies, or labelled antiviral immunoglobulins or antiviral serum from two different species. In addition total free antigen can be measured.

Occurrence of respiratory syncytial virus subtypes in Mexican infants with acute lower respiratory tract disease.

The occurrence of respiratory syncytial virus (RSV) subtypes in Mexico City was studied by searching for the virus in nasopharyngeal aspirates of 82 infants, less than 12 months of age, hospitalized for acute lower respiratory tract disease with diagnosis of bronchitis, bronchiolitis, pneumonia and laryngotracheobronchitis. The presence of respiratory virus was determined by observation of cytopathic effect in cell monolayers; samples which produced a clear syncytia were considered positive and were treated with anti-respiratory syncytial virus serum. Viral infectivity was neutralized in 21 samples which were regarded as having RSV. These specimens were characterized into subtypes A and B with specific monoclonals by indirect immunofluorescence. Subtype A predominated over subtype B, 19 vs. 2. Patients with pneumonia and laryngotracheobronchitis had subtype A and both subtypes were found in infants with bronchitis and bronchiolitis.