The binding of [3H]-tiotidine to homogenates of guinea-pig lung parenchyma.

By use of a rapid filtration assay, the binding of [3H]-tiotidine to homogenates of guinea-pig lung parenchyma was found to be saturable and of a high affinity. Mean values for the KD and Bmax were calculated as 8.5 +/- 1.5 nM and 28 +/- 5 fmol mg-1 protein respectively. The association and dissociation rate constants for [3H]-tiotidine binding at 4 degrees C were calculated to be 0.81 +/- 0.06 microM min-1 and 0.063 +/- 0.005 min-1 respectively, yielding a kinetically derived KD of 7.8 nM. A wide range of H2-receptor agonist and antagonists displaced [3H]-tiotidine binding from lung parenchyma homogenates in a biphasic manner. Examination of the first phase of the displacement of [3H]-tiotidine yielded Ki values for the antagonists tested similar to those found in other binding studies using this ligand and similar to KB values calculated for the antagonists in pharmacological studies.     

Predictors of late hospital death in acute myocardial infarction

Although death from ischemic heart disease occurs in the majority of cases within 24 hr of a new clinical event, study of patients selected by admission to hospital shows a mortality pattern in which most deaths from myocardial infarction happen after the first day. In one hospital, over the last 2 yr, 46% of deaths from infarction have happened from the fourth day onwards. Introduction of a coronary-care unit in this hospital has reduced hospital mortality in patients under 70 yr of age from approximately 21% in 1966–1967 to 13% in 1977–1979, mainly because of improved treatment of arrhythmias. With the decline of cardiac arrhythmias as a mode of dying in hospitals, mechanical complications of shock and cardiac failure now account for up to two-thirds of hospital deaths, with cardiac rupture probably next in importance, accounting for 15%–20% of deaths. Of these 3 mechanisms, death from cardiac failure is most likely to be “late” (from the fourth day onwards). Shock and cardiac failure are directly related to massive destruction of left ventricular myocardium. Therefore, major efforts aimed at reduction of late hospital mortality should be directed towards therapeutic measures, initiated very early after the onset of infarction, which might protect the threatened myocardial tissue and restrict infarct size.     

Intraoperative ultrasound examination of the brain

In a preliminary demonstration of cranial intraoperative real-time ultrasound, both supratentorial and posterior fossa scans displayed the pertinent anatomy. A grade III astrocytoma was visualized on the supratentorial scan as well. Ultrasound may be valuable for surgical planning and biopsy procedures because of its reliable depiction of intracranial anatomy and ease of use.     

Lack of dietary Δ7-sterol markedly shortens the periods of locomotor vigor,reproduction and longevity of adult female Xyleborus ferrugineus (coleoptera,scolytidae)

The sterols cholesterol, 7-dehydrocholesterol and ergosterol were provided as sole dietary sterols to adult female Xyleborus ferrungineus in a chemically defined diet under germ-free conditions and their effects on locomotor (tunneling) vigor, reproductive (ovipositional) capability and survival in relation to animal age were studied. The two dietary Δ⁷-sterols had similar effects on all measured parameters. However, dietary cholesterol markedly shortened the age when 50% of the animals had experienced a termination in each parameter. Changing the environment of the females by the omission of one carbon-carbon double bond, i.e. Δ⁷, in the dietary sterol reduced the mean longevity of life by 36.1%.Experimental data suggest that even when ergosterol, the sterol that the invect normally obtains in its diet, is provided in a nutritionally optimized diet, sterol metabolism plays a major role in the induction of the observed accelerated rates of disability and death with age. The apparent effect of dietary cholesterol is to induce the final, rapid phase of decrement of survival, tunneling and oviposition at markedly earlier ages.