B-cell activation during HIV-1 infection. III. Down-regulating effect of mitogens.

Spontaneous in vitro production of HIV-1-specific antibodies, a hallmark of infected subjects, is often down-regulated by the addition of pokeweed mitogen. We observed that a decrease in such ongoing anti-HIV-1 antibody synthesis could also be induced in cultures from most patients by addition of phytohemagglutinin and Concanavalin A, but not by Epstein-Barr virus, a selective B-cell mitogen. In most cases, this down-regulatory effect of mitogens was evident within the first 24 h of culture. The observed mitogen-associated decrease in spontaneous antibody synthesis was prevented by treating peripheral blood mononuclear cells with agents inhibiting non-major histocompatibility complex-restricted cytotoxic activity or by adding third-party cells to the cultures. In most cases, the mitogen-induced effect was also counteracted by removal of T lymphocytes or CD8+ T-cell sub-population. These findings recall a similar phenomenon observed in normal subjects following intentional immunization, and indicate that mitogen-induced down-regulation of spontaneous in vitro anti-HIV-1-antibody production most probably occurs through a lectin-dependent cytotoxic effect on activated B cells.

Standardization of in vitro synthesis and detection of HIV-1-specific antibodies.

Optimal conditions for in vitro anti-human immunodeficiency virus type 1 (HIV-1) antibody (Ab) synthesis and detection were re-appraised. Western blot (WB) and radioimmunoassay (RIA) could detect about 1 and 10 ng, respectively, of HIV-1-specific Ab (HIV-Ab), while the sensitivity of an enzyme-linked immunosorbent assay (ELISA) was much lower. Optimal HIV-Ab recovery was obtained by culturing 2.5 x 10(6) peripheral blood mononuclear cells (PBMC)/ml from seropositive subjects for 16 days in the absence of mitogens; at higher cell concentrations, background levels were unacceptably high. The background of non-de novo synthesized HIV-Ab was due to insufficient PBMC washing and/or cytophilic immunoglobulin (Ig); a particular washing procedure, as well as 24 h peripheral blood mononuclear cells (PBMC) pre-culture, might help in limiting this phenomenon. However, results should be compared with those obtained in cultures containing puromycin especially in infants, where a higher CD16 antigen expression in lymphocytes is likely responsible for increased amounts of cytophilic Ig released in culture supernatants, compared to adults.

Interferon alpha-2B and ribavirin in combination for patients with chronic hepatitis C who failed to respond to, or relapsed after, interferon alpha therapy: a randomized trial.

PURPOSE: To assess the efficacy of interferon alpha-2b and ribavirin in combination in the treatment of patients with chronic hepatitis C who had either failed to respond to therapy with interferon alpha (nonresponders), or who had relapsed after interferon therapy (relapsers). SUBJECTS AND METHODS: Four hundred patients with chronic hepatitis C (200 nonresponders and 200 relapsers) were randomly assigned in equal numbers to receive either subcutaneous administration of recombinant interferon alpha-2b (3 million units three times per week) and ribavirin (1,000 to 1,200 mg/daily orally) or interferon alpha-2b alone (6 million units three times per week). Both ribavirin and interferon alpha-2b were given for 24 weeks. The patients were then followed for an additional 24 weeks. RESULTS: At the end of the treatment period, normalization of serum alanine aminotransferase levels and absence of hepatitis C virus RNA were seen in 21% of nonresponders and in 39% of relapsers who were treated with interferon alpha-2b and ribavirin, compared with 5% of nonresponders (P = 0.001) and 9% of relapsers treated with interferon alpha-2b alone (P <0.001). At the end of follow-up, 14% of nonresponders and 30% of relapsers treated with the combination therapy had a sustained response, compared with 1% of nonresponders (P = 0.001) and 5% of relapsers treated with interferon alpha alone (P <0.001). CONCLUSIONS: A 24-week course of treatment with interferon alpha-2b and ribavirin offers a chance of sustained response, whereas retreatment with interferon alpha-2b alone does not give satisfactory results. The role of long-term therapy in inducing prolonged remission remains to be explored.

TCR expression and clonality analysis in peripheral blood and lymph nodes of HIV-infected patients.

We compared the T cell receptor (TCR) V beta gene family repertoire in peripheral blood mononuclear cells (PBMC) and lymph node (LN) cells from 7 human immunodeficiency virus (HIV)-infected patients and 3 seronegative healthy controls. Virtually all the V beta family specificities were represented in patient PBMC and LN cells, and mean values for each specificity were comparable to figures in seronegative controls. In 4 patients, however, some V beta gene segment transcripts were overrepresented in the LN compartment, compared to the peripheral blood counterpart. To ascertain whether this phenomenon was due to polyclonal or oligoclonal expansion of T cells bearing the relevant V beta gene product, we sequenced the entire CDR3 region of a panel of 238 PCR clones corresponding to the V beta transcripts expanded in LN; as control, the same regions were cloned and sequenced in patient's PBMC, and in PBMC and LN cells from seronegative individuals. This analysis disclosed preferential usage of J beta 2 genes in PBMC and LN cells from both seropositive patients and controls, regardless of the V beta gene segment considered, thus indicating that this skewness in the V beta-J beta repertoire could be a consistent feature of at least a part of the V beta repertoire in different lymphoid compartments, regardless of the pathologic conditions. In addition, in LN from HIV seropositive patients we found the presence of recurrent TCR rearrangements, accounting for 8-23% of the generated clones, in each of the 4 V beta specificities analyzed; recurrent sequences were not found in PBMC from patients nor in PBMC and LN cells from seronegative controls. These findings suggest that antigen-driven oligoclonal T cell expansions may occur in vivo in lymphoid organs of HIV seropositive patients.

Emergency therapeutical approach simulating ultrarapid opioid detoxification in methadone withdrawal precipitated by erroneous administration of naltrexone.

We report the case of a 30-year-old male, heroin dependent, receiving methadone treatment, who, while staying at home, ingested 50 mg of naltrexone. He immediately developed serious withdrawal symptoms and was admitted to the hospital. In the emergency department the drugs given to counteract the agitation were ineffective, and the patient developed respiratory distress. Anaesthesia with propofol was then started and the patient was intubated, ventilated and hospitalized in the intensive care unit. He was then sedated for 48 hours due to persistent withdrawal signs. When medically stable the patient was transferred to the medical ward where daily treatment with naltrexone and psychological support where started. After 4 days the patient was discharged. Afterwards he did not attend his scheduled outpatient follow-up visits. Treatment with propofol is effective in the case of a patient with a serious withdrawal syndrome secondary to naltrexone overdose during methadone therapy. Despite the actual possibility of getting through the withdrawal symptoms the patient failed to return for follow-up visits, which might be related to a lack of motivation.

What is the best test to predict outcome after prolonged cardiac arrest?

Multimodality evoked potentials (EPs), linear electroencephalograms and Glasgow Coma Scale (GCS) scores were recorded within 24 h of cardiac arrest in 62 patients who were comatose following cardiopulmonary resuscitation. The cardiac arrest had a cardiac cause in 35 patients and a non-cardiac cause in 27 patients. The Glasgow Outcome Scale (GOS) scores were established 6 months after resuscitation. The prognostic value of all the recorded variables was calculated in terms of sensitivity, specificity and accuracy. Spearman's rank test was also used for the determination of the correlation coefficients with GOS. EP recordings furnished no falsely pessimistic predictions, with a specificity of 100%. In other words, when EPs were altered, the prognosis was always poor. However, while all patients who regained consciousness had normal EPs, not all patients in whom EPs were recordable survived. The GCS score showed a higher sensitivity and correlation with GOS score than EPs, but it was associated with a high percentage of false positive results, and its specificity was only 67%. The combination of the GCS score with EPs may be a promising strategy to counterbalance the respective limits of these methods and to reduce the loss of information due to sedation and myorelaxation, which impede clinical examination but not EP results.

Reactivation of oral-lingual herpes by chlorinated swimming pool water: a case report.

The authors describe the case of a highly stressed 36-year-old man who experienced ten or more painful episodes per year of recurrent oral-lingual herpes simplex virus 1, which were only partially responsive to acyclovir therapy for three years. A three-year diary of activities, personal stresses, concurrent infections, local trauma, and other possible psychogenic, somatogenic, and environmental events was used systematically to attempt to pair the stresses with the recurrent herpes episodes. Chlorinated swimming pool water seems to have been the triggering agent of the recurrent herpes simplex virus 1 episodes due to its temporal correlation and the greater than twenty-four-month asymptomatic period after the patient discontinued swimming in chlorinated water, but continued to swim in fresh and salt water, along with his normal pursuit of all other activities and habits.

[Consultations at the Poison Center of Rome on pesticide poisoning referrals]. / Consulenze prestate dai Centri Antiveleni di Roma in riferimento a prodotti antiparassitari.

From 1 January 1998 to 31 October 1999 the two Poison Control Centres active in Rome provided 923 telephone consultations for individuals and health care providers on suspected poisonings involving pesticides. Exposures more frequently reported in association with suspected cases were insecticides (n. 636), including organophosphates (n. 300), carbamates (n. 155), pyrethroids (n. 102), and organochlorines (n. 79). Children aged 1-4 years accounted for 22% of all suspected poisonings (n. 200). Each case was classified as to the likelihood of a relationship between the reported pesticide exposure and the occurrence of health effects. Around 18% of suspected pesticide poisonings (n. 168) were subsequently classified as definite, around 43% (n. 390) as possible, and around 37% were considered unlikely (n. 344).

[Brain mapping of middle latency auditory potentials in normal subjects]. / Mappaggio cerebrale dei potenziali uditivi a media latenza in soggetti normali.

The MLRs of 20 normal hearing adults were recorded by cerebral mapping. In regard to the Pa and Na waves, it is suggested that two different generation sites exist because of the different spatio-temporal distribution of the waves over the scalp. It is demonstrated that amplitudes measured by the "grand average" technique are constantly lower than those obtained with the manual determination, and they conclude that manual determination represents the most reliable method in order to calculate waves amplitude. Finally, it is suggested that, due to the different generation sites for Pa and Na waves and to the uneven distribution of the Na wave over the scalp, Pa amplitude should be measured from the baseline and not from the Na negative deflection. Moreover, in 14 cases, when one ear was stimulated the Pa wave obtained at most recording points was significantly larger than the one recorded contralaterally.

[Computerized multiple-choice questions: an efficacious method of evaluation in medical instruction?]. / Domande a scelta multipla computerizzate: un metodo di valutazione efficace nella didattica medica?

To evaluate the efficacy of Multiple Choice Questions (MCQ) as an evaluation tool in medical education, were analyzed the responses to 80 MCQ delivered by 300 physicians working in emergency departments and following a course on Basic and Advanced Life Support. Pre- and post-test were administered using a dedicated computer application running on PC. Students' scores were high and demonstrated both course and test validity. More than 95% of the students used the computer application without interface difficulties. However, some limits of MCQ were individuated: first, misinterpretation of some questions, especially when two or more similar answers were presented; from the other side, the student's personal experiences during the course practice could influence student's responses bringing him to different conclusions on respect to the instructor. These difficulties should be kept in mind in the development of a MCQ session, and students should have the possibility to give to the instructor a feedback of problems encountered during the course. This is especially important when MCQ are the sole evaluation technique.

New experimental Oximes in the management of organophosphorus pesticides poisoning.

Organophosphorus compounds (OPCs) are widely used in agriculture as pesticides and occasionally in industrial settings. They have also been developed as warfare nerve agents. OPCs poisoning from intentional, accidental, and occupational exposure is a major public health problem, especially across the rural developing world. The main toxic mechanism of OPCs is the inhibition of the enzymes acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE), resulting in accumulation of acetylcholine (ACh) at the synapse with cholinergic crisis and possible death. Exposure to even small amounts of an OPC can be fatal and death is usually caused by respiratory failure. Standard treatment involves the administration of intravenous atropine and an oxime to counteract acetylcholinesterase inhibition at the synapse, but the usefulness of oximes is still debated. During more than five decades, pyridinium oximes have been developed as therapeutic agents used in the medical treatment of poisoning with OPCs. They act by reactivation of AChE inhibited by OPCs. However, their activity in poisonings with pesticides and warfare nerve agents is different, and there is still no universal oxime sufficiently effective against all known OPCs. The aim of this article was to review the most recent findings in this field and compare the protection conferred by the new K-oximes and sugar oximes with the effect of the four recommended pyridinium oximes (pralidoxime, obidoxime, trimedoxime, and HI-6), in the search for a broad-spectrum AChE reactivator.