Quantitative ELISA for mouse monoclonal antibody determination in culture supernatants and in human serum

An ELISA has been set up for quantifying mouse monoclonal antibodies in culture supernatant. The assay includes rabbit anti-mouse IgG antibodies chromatographycally purified. This preparation was used as coating and as conjugated antibodies in the ELISA. The assay can detect IgG1 with sensitivity of 0.2 ng/mL, IgG2a (0.85 ng/mL), IgG2b (0.13 ng/mL), and IgG3 (3.19 ng/mL) in culture supernatants. The effective working range was from subnanogram per mL quantities to 30 ng/mL by using a computer statistical program. Variation coefficient of ELISA was below 7%. Correlation estimates with a similar ELISA using commercial reagents were performed for each mouse antibody subclass. The assay was able to detect the four mouse monoclonal antibody subclasses in pure human serum as compared with the same ELISA using commercial antibodies. A 24-h pharmacokinetic profile of 1 patient treated with an IgG2a monoclonal antibody is presented.

What happened to life expectancy in Spain in the 1980s?

BACKGROUND

Life expectancy at birth in Spain improved between 1972 and 1982, by 2.5 years for males and 3.2 years for females. This slowed considerably in the following decade, with increases of only 0.5 and 1.7 years respectively.

OBJECTIVE

To determine the causes of death that have been responsible for the failure by Spain to maintain in the 1980s and 1990s the rate of improvement in life expectancy seen during the 1970s.

DESIGN

Data from WHO mortality tapes grouped in a series of clinically meaningful categories were used to calculate the contribution of each category, in five year age groups, to the changing life expectancy at birth in the two periods.

SETTING

Spain.

RESULTS

The trend in life expectancy at birth in Spain over this 20 year period can be considered to have two components, both with important consequences for public health policy. Underlying trends include a steady negative contribution from respiratory cancer in men and a reduction in cardiovascular disease. More recent trends include a considerable deterioration in deaths among young adults, most notably from accidents and, possibly, AIDS.

CONCLUSION

The failure to maintain the rate of earlier gains in life expectancy in Spain can be attributed largely to a few conditions, although these may indicate less obvious underlying problems. These findings have important consequences for prioritising public health policies.

Molecular characterization of an outbreak of respiratory syncytial virus (subgroup A) in Havana, Cuba, by monoclonal antibodies and restriction mapping (N gene)

Twenty-one respiratory syncytial virus (RSV) strains isolated from one outbreak in Havana, Cuba (1994 to 1995), were analyzed to determine their relatedness. All isolated strains were classified as subgroup A by monoclonal antibodies. Of 21 RSV strains examined, 20 were classified as having restriction pattern NP4 and only 1 was classified as having restriction pattern NP5.

Monoclonal antibodies raised to the dengue-2 virus (Cuban: A15 strain) which recognize viral structural proteins

Mouse monoclonal antibodies (MAbs) were raised to dengue-2 virus (D-2V) Cuban (A15) strain and the cell culture supernatants were screened by ELISA using the homologous virus. Three MAb-secreting lines were further characterized using immunoblot, haemaglutination, complement-fixation, and neutralization assays. One of these, MAb 8H8, weakly reacted with the viral nonstructural-1 protein (NS1) but more specifically identified the capsid protein (C), MAb 3E1 recognized in serological assays D-2V A15 but it had a weak reaction to C protein by immunodetection whereas another, MAb 4G3, weakly neutralized the homologous virus isolate and blocked the binding of specific anti-envelope (E) Mab, and its reaction with this protein could not be confirmed using immunoblot assays. These reagents are now being used to compare virulent plus avirulent Caribbean viruses antibody dependent enhancement (ADE) assays.

Analysis of respiratory syncytial virus in clinical samples by reverse transcriptase-polymerase chain reaction restriction mapping

The aim of this study was to develop a polymerase chain reaction (PCR) for the detection of respiratory syncytial virus (RSV) genomes. The primers were designed from published sequences and selected from conserved regions of the genome encoding for the N protein of subgroups A and B of RSV. PCR was applied to 20 specimens from children admitted to the respiratory ward of "William Soler" Pediatric Hospital in Havana City with a clinical diagnosis of bronchiolitis. The PCR was compared with viral isolation and with an indirect immunofluorescence technique that employs monoclonal antibodies of subgroups A and B. Of 20 nasopharyngeal exudates, 10 were found positive by the three assayed methods. In only two cases, samples that yielded positive RNA-PCR were found negative by indirect immunofluorescence and cell culture. Considering viral isolation as the "gold standard" technique, RNA-PCR had 100% sensitivity and 80% specificity. RNA-PCR is a specific and sensitive technique for the detection of the RSV genome. Technical advantages are discussed.

[Bipolar II disorder: course and suicidal behavior]

INTRODUCTION

Bipolar II disorder seems to be more than a mild form of classic manic-depressive illness. Differences with bipolar I concern genetic, biological, clinical and pharmacological aspects. Nevertheless, studies on suicidal behavior in both groups have resulted in inconsistent results

PATIENTS AND METHOD

Twenty-two patients fulfilling Research Diagnostic Criteria for the diagnosis of bipolar II disorder and 38 bipolar I were evaluated with the Schedule for Affective Disorders and Schizophrenia by two independent interviewers, and compared.

RESULTS

Bipolar II patients had significantly more previous episodes (p = 0.001), including both depressive (p = 0.003) and hypomanic switches (p = 0.006), but had been hospitalized (p = 0.001) and presented psychotic symptoms (p < 0.001) less frequently.

CONCLUSIONS

There were no significant differences between both groups regarding suicidal behavior variables. These results suggest that bipolar II disorder is less severe than bipolar I regarding symptoms intensity, but more severe with respect to episodes frequency, and that suicide attempts rates are not useful to discriminate between both groups.

Differential features between bipolar I and bipolar II disorder

Although bipolar II disorder is generally viewed as a mild form of classic manic-depressive illness, recent investigations suggest that it could be a valid diagnostic category different from bipolar I in genetic, biological, clinical, and pharmacological aspects. Twenty-two patients fulfilling Research Diagnostic Criteria for the diagnosis of bipolar II disorder and 38 bipolar I patients were evaluated with the Schedule for Affective Disorders and Schizophrenia by two independent interviewers and compared. Bipolar II patients had significantly more previous episodes (P = .001), including both depressive (P = .003) and hypomanic (P = .006) switches, but had been hospitalized (P = .001) and presented psychotic symptoms (P < .001) less frequently. These results suggest that bipolar II disorder is less severe than bipolar I with regard to symptom intensity, but is more severe with respect to episode frequency.

Prediction of depressive relapse in remitted bipolar patients using corticotrophin-releasing hormone challenge test

Abnormalities in corticotrophin (ACTH) and cortisol levels before and after corticotrophin-releasing hormone (CRH) stimulation have been reported in depressed bipolar patients. The ACTH and free cortisol response to the injection of 100 micrograms of synthetic human CRH and plasma cortisol-binding globulin (CBG) levels were measured in 42 lithium-treated patients suffering from RDC bipolar-I disorder in remission, and in 21 age- and sex-matched control subjects. A 1-year follow-up was conducted in order to assess any possible relationship between outcome and the hormonal response. Bipolar patients showed higher baseline and peak ACTH concentrations than controls. A lower net area under the ACTH concentration curve after CRH stimulation predicted depressive relapse within 6 months by multiple regression analysis. The CRH challenge test could be a potentially good predictor of depressive relapse in remitted bipolar patients.

[Traumatic asphyxia and continuous venovenous hemofiltration. Report of a case]

A 32-year-old man was admitted with traumatic asphyxia, with aspiration to the bronchi after being buried under sand. The condition progressed to respiratory distress syndrome and systemic inflammatory response. Because ventilatory and hemodynamic deterioration was rapid and severe, in spite of mechanical ventilation and vasoactive drugs, we instated early continuous arteriovenous hemofiltration, which also allowed us to meet the patient's full nutritional needs. We believe that the patient's very satisfactory progress can be attributed to the early use of this procedure, along with appropriate specific treatment.

Characterization and extracellular activity of psychrotrophic bacteria isolated from Villalón cheese (fresh variety of Spanish sheep's milk cheese)

The incidence of psychrotrophic bacteria was investigated in a Spanish fresh ewes' cheese (Villalón). Counts of mesophiles and psychrotrophs were (log cfu/g) 5.72 +/- 1.10 and 3.90 +/- 1.01, respectively, for factory cheeses made from pasteurized-milk. Figures for hand-made cheeses made from raw-milk were 7.35 +/- 0.48 and 6.94 +/- 0.65, respectively. A total of 59 representative psychrotrophic isolates were characterized and tested for protease and lipase production at 7 and 30 degrees C. The strains were assigned to Enterobacteriaceae (predominant in raw-milk cheese), heterofermentative lactic acid bacteria (dominant in pasteurized-milk cheese and absent in raw-milk cheese) and Pseudomonas. More than 73% of the Enterobacteriaceae produced both proteolytic and lipolytic enzymes at either 30 or 7 degrees C. This percentage is considerably higher than those previously reported. The seven isolates of pseudomonads investigated produced proteases at 7 degrees C and six were positive at 30 degrees C; lipolytic activity was shown by five of the isolates at both temperatures. Among the heterofermentative lactic acid bacteria seven of the ten isolates were proteolytic at 30 degrees C.

[Minimally invasive coronary surgery. Thoracostomy-assisted thoracotomy. Apropos a case]

CLINICAL CASE PRESENTATION: Male, 62 years old with progressive angina. Positive stress test. At catheterization a proximal 90% stenosis of the LAD was found. Not suitable for PTCA.

SURGICAL TECHNIQUE

Double lumen endotracheal tube was inserted. Position was 30 degrees right lateral decubitus. The thoracoscope was introduced through the 7th intercostal space and a minithoracotomy was done. The internal mammary artery (IMA) was dissected partially through direct vision and partially with the help of the thoracoscope. The IMA graft was implanted to the LAD without cardiopulmonary bypass with a segmentary occlusion of the vessel with tourniquets.

EVOLUTION

Thoracic drainage 575 cc, CK/MB 311/5, final hematocrit 37%. No blood transfusion. Dismissed on the 5th postoperative day.

Distinctive control of metabolic pathways by Chlorella autotrophica in semicontinuous culture

The marine microalga Chlorella autotrophica was cultured semicontinuously under light-dark synchronizing conditions at two nutrient concentrations (2 and 4 mmol N.L-1) and five rates of daily renewal (from 10 to 50% of culture volume). Under such conditions, the biochemical composition of C. autotrophica was strongly influenced by the renewal rate, but unlike other marine microalgae, the nutrient concentration had no effect on the biochemical composition of the organic fraction of the microalga at a given growth rate. Results suggest that this species exerts a strong control over metabolic pathways, independent of the nutrient concentration in the medium.

Analyses of functional antibody responses in HIV-1-infected individuals after vaccination with rgp160

BACKGROUND

The immune response to HIV infection has been extensively studied and the antibody response against the virus has been characterized in detail. It is, however, still unclear which immune function it is most important to stimulate when administering a vaccine against HIV.

OBJECTIVES

To analyze the functional antibody responses in asymptomatic HIV-1-infected individuals after vaccination with rgp160.

STUDY DESIGN

Forty-nine asymptomatic HIV-1-infected individuals were followed for 9 months and analyzed for changes in functional antibody responses. Forty of them received HIV-1 envelope rgp160 injections and nine did not.

RESULTS

Increased levels of antibodies mediating neutralization and cellular cytotoxicity (ADCC) could be seen in subjects who also showed a better CD4 development compared with the patients without increased levels of functional antibodies. Out of nine matched HIV-infected and influenza-immunized controls, none had increased neutralizing activity and only one had an increased ADCC titer. An increased capacity to block soluble CD4 binding to gp120 occurred in 10 immunized patients. Seroreactivity and avidity maturation were detectable to peptides representing consensus HIV-1 envelope regions, indicating an anamnestic response to the patients own virus.

CONCLUSIONS

The humoral immune response in HIV-1-infected individuals was moderately influenced by repeated gp160 immunizations, while previous studies have shown that HIV-specific T-cell reactivity was strongly increased.

[The effect of angioplasty on cerebral vasomotor reactivity in patients with important stenosis of the internal carotid artery]

INTRODUCTION

We present the preliminary results of the effects on percutaneous translumenal angioplasty (PTA) cerebral haemodynamics in thirty patients with important stenosis of the internal carotidal artery.

MATERIALS AND METHODS

Using transcranial doppler (TCD) with acetazolamide (ACZ) as a vasodilatory stimulus, we assessed vasomotor reactivity (VR and pulsatility index (Pl) both before and three months after angioplasty. We also carried out single photon emission computerized tomography (SPECT) and cartography and frequency measurement by electroencephalogram (EEG) again both before and after PTA.

RESULTS

Of the first twelve patients who completed the study, VR was maintained in nine and PI increased after PTA in seven. In three patients VR was exhausted and in two recovered after PTA.

CONCLUSIONS

PTA improved cerebral haemodynamics. Similar more exhaustive studies are needed if revascularization techniques are to be useful in treating patients with this level of stenosis but who are asymptomatic as to the risk of haemodynamic cerebral vasomotor angioplasty.

Optimal Renewal Rate and Nutrient Concentration for the Production of the Marine Microalga Phaeodactylum tricornutum in Semicontinuous Cultures

A factorial experiment comprising six nutrient concentrations and six renewal rates was set to optimize semicontinuous cultures of Phaeodactylum tricornutum. Maximal cell density, 85 x 10(sup6) cells ml(sup-1), was obtained with 8 and 16 mmol of N per liter and a renewal rate of 10%. Protein stabilized at about 60% of the organic fraction for nitrogen-sufficient cultures. Both lipids and carbohydrates were stored as energetic reserves.