Determination of progesterone in saliva using an electrochemical immunosensor and a COTS-based portable potentiostat.

This paper describes the reliable determination of progesterone (P4) in undiluted saliva making use of a disposable amperometric immunosensors implemented on low-cost and portable device/potentiostat constructed with commercial-off-the-shelf (COTS) components. The immunosensor allows the fast (45 min), selective and sensitive determination (5 pg mL-1 LOD) of P4 using amperometry in stirred solutions. The immunosensor was coupled to the COTS-based potentiostat and amperometry was made into drops of quiescent solutions. No significant differences were apparent between the analytical performance achieved with the immunosensor for P4 using both a conventional and the COST-based potentiostats. The practical applicability of the immunosensor coupled with the COTS-based potentiostat was demonstrated by determining the endogenous P4 content in different undiluted saliva samples with highly variable endogenous contents of the target hormone. The obtained results were in good agreement with those provided by the conventional ELISA methodology and with the contents reported in the literature for samples with similar characteristics. This validated the combined device for the reliable and minimally invasive determination of the target hormone involving a very simple protocol and taking only 45 min.

Patterns of acute inferior wall myocardial infarction caused by hyperkalemia.

This is one of the first published articles dealing with two patients with hyperkalemia showing, not only a pattern of acute anteroseptal myocardial infarction, but of inferior myocardial infarction as well. This was attributed to uneven effects of high potassium in different regions of the heart. Marked reduction of resting potential of a large group of cells from the most affected regions could produce areas of inexcitability, capable of generating abnormal q waves. Likewise, ST-segment elevation could be attributed to a hyperkalemic diastolic current of injury (due to depolarization of resting potential) and to a combination of diastolic and systolic current of injury (due to a reduction of action potential amplitude). In addition, current flowing down voltage gradients on either side (epicardial and endocardial) of the M cell region could be responsible for the T wave, and even, to some extent, to the ST-segment changes. However, it cannot be excluded that the previously described changes may have resulted from coronary spasm without chest pain. In fact, an intriguing possibility, namely that hyperkalemia could trigger coronary spasm has to be considered also.

Reverse alternating Wenckebach periods and other modes of regression of > or = 8:1 to 2:1 atrioventricular block.

The modes of regression of very high degrees of atrioventricular nodal block (> or = 8:1) were studied in patients with atrial flutter and a specific variant of the tachycardia-bradycardia syndrome. The occurrence of reverse alternating Wenckebach periods, previously reported only in 2:1 atrioventricular block, emphasizes the complexities of multilevel block.

[Dermatomycosis in plaques caused by Botryomyces caespitosus. A new causative agent]. / Dermatomicosis en placa por Botryomyces caespitosus. Nuevo agente causal.

The clinical and histological features of a dermomycosis caused by a new dematiaceum fungus are described. The mycological characteristics of this fungus individualize and differentiate it from other demiataceum hyphomycetes, proposing the name of Botryomyces caespitosus for it. The submicroscopic features are commented, as well.

[Headache affecting the pigmented zones of Ota's naevus: clinical study in four cases (author's transl)]. / Etude clinique sur les céphalées pigmentaires des patients porteurs de naevus de Ota.

Four women, aged between 23 and 69 years, who had developed Ota's naevi either during the menarche (3 cases) or the first pregnancy (1 case), complained of headache in the frontal and orbital zones affected by the naevi. These headaches bore no relationship to those normally described as occurring in this region. They increased in severity, at the same time as the intensity of the pigmentation of the naevus, in each patient during the menstrual periods, and did not respond to conventional analgesics.