RESUMEN
We investigated the alteration of coagulation state in a protein C (PC) deficiency pedigree and the impact of the PC gene mutations. The pedigree of a proband with cerebral hemorrhagic infarction had sixteen members with four generations. The plasma levels of PC activity (PC:A), protein S activity (PS:A), factor V:C and factor VIII:C, and routine coagulation tests were measured. Nine exons of the PC gene (PROC) were sequenced. Plasma PC:A and PC antigen (PC:Ag) of the proband were 26 and 18%, respectively, which was significantly lower than normal ranges. Two heterozygous missense mutations of PC in the proband were identified, T>G at site 6128 (exon 7) and G>C at site 8478 (exon 9) resulting in F139V and D255H, respectively. The family members with F139V (N = 4) or D255H (N = 4) had lower levels of PC:A and PC:Ag than members with wild-type PROC (N = 6). D255H mutation caused a more significant decrease in the levels of PC:A, PC:Ag and factor V:C as compared to F139V mutation (P < 0.05). Two independent mutations, F139V and D255H, of PROC reduce PC function. Compound heterozygous condition of the two mutations can cause synergistic PC deficiency, but resulting in later onset of cerebral thrombosis.
Asunto(s)
Deficiencia de Proteína C/genética , Proteína C/genética , Trombosis/genética , Adolescente , Adulto , Edad de Inicio , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Exones , Femenino , Heterocigoto , Humanos , Masculino , Persona de Mediana Edad , Mutación Missense , Linaje , Deficiencia de Proteína C/patología , Trombosis/patologíaRESUMEN
Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central integration of these autonomic pathways. The visceral afferent synapse is uncommonly powerful at the NTS with large unitary response amplitudes and depression rather than facilitation at moderate to high frequencies of activation. Substantial signal depression occurs through multiple mechanisms at this very first brainstem synapse onto second order NTS neurons. This review highlights new approaches to the study of these basic processes featuring patch clamp recordings in NTS brain slices and optical techniques with fluorescent tracers. The vanilloid receptor agonist, capsaicin, distinguishes two classes of second order neurons (capsaicin sensitive or capsaicin resistant) that appear to reflect unmyelinated and myelinated afferent pathways. The differences in cellular properties of these two classes of NTS neurons indicate clear functional differentiation at both the pre- and postsynaptic portions of these first synapses. By virtue of their position at the earliest stage of these pathways, such mechanistic differences probably impart important differentiation in the performance over the entire reflex pathways.
Asunto(s)
Barorreflejo/fisiología , Sistema Cardiovascular/inervación , Núcleo Solitario/fisiología , Transmisión Sináptica/fisiología , Aferentes Viscerales/fisiología , HumanosRESUMEN
Visceral afferents send information via cranial nerves to the nucleus tractus solitarius (NTS). The NTS is the initial step of information processing that culminates in homeostatic reflex responses. Recent evidence suggests that strong afferent synaptic responses in the NTS are most often modulated by depression and this forms a basic principle of central integration of these autonomic pathways. The visceral afferent synapse is uncommonly powerful at the NTS with large unitary response amplitudes and depression rather than facilitation at moderate to high frequencies of activation. Substantial signal depression occurs through multiple mechanisms at this very first brainstem synapse onto second order NTS neurons. This review highlights new approaches to the study of these basic processes featuring patch clamp recordings in NTS brain slices and optical techniques with fluorescent tracers. The vanilloid receptor agonist, capsaicin, distinguishes two classes of second order neurons (capsaicin sensitive or capsaicin resistant) that appear to reflect unmyelinated and myelinated afferent pathways. The differences in cellular properties of these two classes of NTS neurons indicate clear functional differentiation at both the pre- and postsynaptic portions of these first synapses. By virtue of their position at the earliest stage of these pathways, such mechanistic differences probably impart important differentiation in the performance over the entire reflex pathways.