Blood Pressure Changes in Man during Infrasonic Exposure

ABSTRACT. Danielsson Å. LandstrÖm U. (Department of Internal Medicine, University Hospital, and National Board of Occupational Safety and Health, UmeÅ, Sweden.) Blood pressure changes in man during infrasonic exposure. Twenty healthy male volunteers were exposed to infrasound in a pressure chamber especially designed for the experiments. The effects on blood pressure, pulse rate and serum cortisol levels of acute infrasonic stimulation were studied in a series of different experiments. Varying frequencies (6, 12, 16 Hz) and pressure levels (95, 110, 125 dB(lin)) were tested. Significantly increased diastolic and decreased systolic blood pressures were recorded without any rise in pulse rate. The increase in diastolic blood pressure reached a maximal mean of about 8 mmHg after 30 min exposure. The results suggest that acute infrasonic stimulation induces a peripheral vasoconstriction with increased blood pressure, previously shown to occur in conjunction with industrial noise. Chronic long-term exposure to environmental infrasound may be of importance for the development of essential hypertension in predisposed individuals.     

Arterial Blood Pressure and General Sympathetic Activation in Essential Hypertension during Stimulation

ABSTRACT We asked whether exaggerated blood pressure (BP) reactivity in patients with essential hypertension (HT) is a sign of specific activation of the cardiovascular system or of generalized sympathetic activation. Fourteen patients with essential hypertension and 14 matched normotensive (NT) controls were subjected to tasks involving attentional demands, mental arithmetic, a cold pressor test and isometric muscular contraction. Systolic and diastolic BPs, skin and muscle blood flows, heart rate, skin conductance level and fluctuations during each task were recorded. Urine samples for determination of epinephrine and norepinephrine excretion were collected after task completion. All tasks caused BP increases in both groups. HT showed greater absolute and percentage BP reactivity than NT during isometric muscle contraction. Variables for which reactivity differences were observed were poorly correlated across tasks both in HT and NT, whereas resting values prior to each task were highly correlated in both groups. Skin conductance activity, epinephrine and norepinephrine excretion rates being examples of non-cardiovascular sympathetic nervous system (SNS) indicators did not separate HT from NT. Thus, the exaggerated pressor response in HT is not accompanied by signs of generalized SNS activation.     

A quantitative structure-activity relationship study of some substance P-related peptides A multivariate approach using PLS and variable selection

Nine new analogues of substance P (SP) were designed using quantitative sequence-activity models based on the amino acid z-scales with PLS as the statistical method and the GOLPE procedure for variable selection. The nine SP analogues were synthesised by solid-phase peptide synthesis and tested for affinity to the NK-1 receptor from rat brain with radio receptor assay using [¹²⁵I]-Bolton-Hunter substance P as labelled ligand. All of the new substance P analogues showed high affinities, with IC₅₀ values of less than 0.8 nM. One analog, Lys-Arg-Ala-Lys-Phe-Met-Met-Phe-Phe-Gly-Leu-Let-NH₂, showed a exceptional high affinity for the NK1 receptor, with IC₅₀= 5 PM.     

In what respect does high frequency positive pressure ventilation differ from conventional ventilation?

The original rationale for HFPPV was that under certain conditions adequate alveolar ventilation could be achieved with high ventilatory frequencies and small tidal volumes. It was theorized further that increased ventilatory frequencies and low tidal volumes would decrease the airway pressures, barotrauma, and cardiovascular and other systemic consequences seen with conventional mechanical ventilation. The first clinical applications of HFPPV were in bronchoscopy and laryngoscopy for diagnostic and/or therapeutic purposes. Apart from these endoscopic applications, volume-controlled HFPPV has been compared with conventional ventilation in upper abdominal surgery and coronary artery bypass grafting. The possible advantages of HFPPV over conventional volume-controlled ventilation in the intensive care setting are still unclear. Provided that the mean lung volumes are similar, oxygenation in acute respiratory failure is similar with both ventilation methods. Although the role of HFPPV in the management of pulmonary diseases still remains to be clarified, it does provide effective ventilation in selected types of patients needing ventilatory support. New modes of pressure-controlled ventilation have not resolved all clinical problems in severe ARDS and/or acute respiratory failure. The search for means of optimal ventilatory support with minimal complications must continue, as conventional ventilation does not always offer the best treatment.     

Diagnosis and Management of Acute Aortic Dissection,Clinical and Radiological Follow-up

ABSTRACT A clinical series of acute aortic dissections is presented. Twenty cases were of type A and 10 of type B. Acute severe chest pain was common, in type A also blood pressure difference between the arms and aortic regurgitation. The diagnosis was established by echocardiography, computerized tomography and/or aortography. Antihypertensive therapy was instituted immediately after diagnosis and was in type A cases followed by acute surgery unless definite contraindications existed. Of 14 surgically treated type A patients 13 survived the operation. On follow-up 1.5–3.5 years later, 12 patients were still alive and doing well, but the false channel remained open in all cases where it had not been resected totally. Only one of six conservatively treated type A patients survived. Type B dissections were operated on only if conservative therapy failed. Four of five conservatively and two of five surgically treated type B patients survived.     

SEQUENTIAL DETERMINATION OF C-REACTIVE PROTEIN IN ACUTE CHILDHOOD PYELONEPHRITIS

Abstract. Serum CRP levels ranging between 10 and 200 μg/ml were found in 19 patients with acute pyelonephritis. Treatment with antibacterial drugs, to which the bacteria were fully sensitive, resulted in a rapid decrease of the CRP values and very low or trace amounts were attained within a week. In contrast, cases ineffectively treated and/or reinfected showed increasing or slowly decreasing CRP levels. It is suggested that repeated CRP determinations can be used as a diagnostic tool for the rapid detection of cases of acute pyelonephritis in which treatment is ineffective.     

Hypereosinophilic syndrome in a child mosaic for a congenital triplication of the short arm of chromosome 8

An 11-year-old boy with mental retardation, malformations, and the mosaic karyotype 47,XY,+i(8p)/46,XY presented with fever, headache and petechiae. Peripheral blood WBC was 190 ×10⁹/l; and contained > 90% mature eosinophils. Cytogenetic analysis of the eosinophils revealed no aberrations except the constitutional karyotype. The patient was diagnosed as having a hypereosinophilic syndrome. Shortly after initiation of therapy he died from extensive mural thrombi of the heart and thrombi of several other organs. This is the first case of congenital triplication of the short arm of chromosome 8 associated with hypereosinophilic syndrome, suggesting involvement of genes on chromosome 8p in the regulation of eosinopoiesis.