Pupil responsiveness in cluster headache: A dynamic TV pupillometric evaluation

In this study the variations in pupil diameter induced by different stimuli (dark-light adaptation, light reflex, electric stimulation of the sural nerve) were investigated in episodic (in the active or remission phases) and in chronic cluster headache (CH) patients. Pupil size monitoring was performed with a monocular, infrared TV pupillometer, and sural nerve stimuli were applied after the pain threshold had been measured as the flexion reflex threshold of the biceps femoris muscle (RIII reflex). The results were compared with those obtained in patients with "peripheral" (third neuron) Horner's syndrome and in healthy sex- and age-matched controls. On the symptomatic side we found an impairment of pupil response to light flashes and nociceptive stimuli; similar findings were sometimes evident on the pain-free side, too. These results substantiate previous observations that in cluster headache a dysfunction of the integrative central nervous system pathways also exists intercritically and mostly bilaterally, involving both autonomic regulation and pain perception mechanisms.     

Phenotypic and functional characteristics of tumor-associated lymphocytes in patients with malignant ascites receiving intraperitoneal infusions of recombinant interleukin-2 (rIL-2)

In the course of a phase I trial, in which recombinant IL-2 (rIL-2) was infused intraperitoneally (i.p.) in patients with peritoneal carcinomatosis, we evaluated the effect on "tumor-associated lymphocytes" (TAL) isolated from the ascitic fluid. No major changes in the percentages of cells expressing the CD3, CD4, CD8, Leu-7, OKM1 and WT-31 antigens were detected either in TAL or in peripheral blood lymphocytes (PBL) after 7 days of rIL-2 infusion. In contrast the percentages of TAL (but not PBL) expressing surface IL-2 receptor (Tac), or LAK-1 antigen were sharply increased. Analysis of cytolytic functions showed a potentiation of the lytic activity against natural-killer (NK) sensitive K562 target cells and the de novo appearance of lytic activity against fresh melanoma cells. In one patient IFN-gamma was detected in the ascitic fluid following rIL-2 infusion. T-cell clones derived from the patient were analyzed for the IFN-gamma production. While only approximately 40% of PB-derived control clones produced medium to low amounts of IFN-gamma, all of the TAL-derived clones produced medium to high amounts of the lymphokine.     

Evolution of foot-and-mouth disease virus

Foot-and-mouth disease virus evolution is strongly influenced by high mutation rates and a quasispecies dynamics. Mutant swarms are subjected to positive selection, negative selection and random drift of genomes. Adaptation is the result of selective amplification of subpopulations of genomes. The extent of adaptation to a given environment is quantified by a relative fitness value. Fitness values depend on the virus and its physical and biological environment. Generally, infections involving large population passages result in fitness gain and population bottlenecks lead to fitness loss. Very different types of mutations tend to accumulate in the foot-and-mouth disease virus (FMDV) genome depending on the virus population size during replication. Quasispecies dynamics predict higher probability of success of antiviral strategies based on multivalent vaccines and combination therapy, and this has been supported by clinical and veterinary practice. Quasispecies suggest also new antiviral strategies based on virus entry into error catastrophe, and such procedures are under investigation. Studies with FMDV have contributed to the understanding of quasispecies dynamics and some of its biological implications.     

Spontaneous coronary artery dissection mimicking aortic dissection

A 51-year-old woman suffered rapidly irreversible cardiogenic shock with left hemiparesis. Transesophageal echocardiography, which represents an essential imaging tool in the emergency room, ruled out aortic dissection involving branch vessels but did not allow an in vivo diagnosis of spontaneous coronary dissection. The in vivo diagnosis of spontaneous coronary dissection is rather difficult because of the dramatic clinical presentation and selective coronary angiography requirement.     

The molecular basis of Natural Killer (NK) cell recognition and function

Natural Killer cells are likely to play an important role in the host defenses because they kill virally infected or tumor cells but spare normal self-cells. The molecular mechanism that explains why NK cells do not kill indiscriminately has recently been elucidated. It is due to several specialized receptors that recognize major histocompatibility complex (MHC) class I molecules expressed on normal cells. The lack of expression of one or more HLA class I alleles leads to NK-mediated target cell lysis. Different types of receptors specific for groups of HLA-C, HLA-B, and, very recently, HLA-A alleles have been identified. While in most instances, they function as inhibitory receptors, an activatory form of the HLA-C-specific receptors has been identified in some donors. Molecular cloning of HLA-C-, HLA-B- or HLA-A-specific receptors has revealed new members of the immunoglobulin superfamily with two or three Ig-like domains, respectively, in their extracellular portion. While the inhibitory form is characterized by a long cytoplasmic tail associated with a non-polar transmembrane portion, the activatory one has a short tail asociated with a Lys-containing transmembrane portion. Thus, these human NK receptors are different from the murine Ly49, that is a type II transmembrane protein characterized by a C-type lectin domain. A subset of activated T lymphocytes expresses NK-type class I-specific receptors. These receptors exert an inhibiting activity on T cell receptor-mediated functions and may provide an important mechanism of downregulation of T cell responses.     

An ELISA serum assay for autoantibodies to HSP70 in immune-mediated hearing loss

A Western blot to detect anti-HSP70 autoantibodies has been reported to be of diagnostic value for immune-mediated hearing loss patients. While setting up this Western blot in our lab, we detected two main problems. First, some patients were positive for antibodies to a 70-kDa protein when tested against a whole cell lysate, but negative if the antigen used was purified HSP70. Second, if high amounts of purified HSP70 were loaded on the gel, both patients and healthy controls were positive. We have developed and optimized an ELISA as an alternative to the Western blot. This assay is more appropriate to identify positive and negative individuals because it is semi-quantitative. The ELISA is also more sensitive, requiring very low concentrations of the antigen and thus minimizing false positives. Finally, we demonstrated that immune-mediated hearing loss patients recognize mainly the native form of HSP70, a fact that potentially leads to false negatives when a denaturing Western blot assay is used for diagnosis. To test the diagnostic value of the ELISA, we performed a blind test with 70 hearing loss patients, as well as 30 healthy controls. A sensitivity of 84% and a specificity of 93% were obtained, superior to what has been reported so far for the Western blot.