Some characteristics of TRH-induced grooming behavior in rats

Intracerebroventricular administration of TRH induces excessive grooming behavior that is characterized by an important contribution of the elements scratching and paw licking. As compared with other grooming inducing peptides, the pattern of TRH-induced grooming resembles that induced by beta-endorphin rather than those elicited by ACTH or bombesin. TRH-induced excessive grooming is suppressed by pretreatment with haloperidol, naloxone or neurotensin. Haloperidol suppresses TRH-induced grooming in a general way, whereas the suppressive effect of the other drugs is mainly due to a selective reduction of TRH-induced excessive scratching. Combined treatments of rats with TRH and a submaximal dose of ACTH, bombesin or beta-endorphin do not result in higher grooming scores than with single peptide treatment. Excessive grooming elicited by water immersion is not affected by TRH. It is concluded that TRH is undoubtedly an excessive grooming inducing peptide. In situations where excessive grooming is elicited by other peptides or by water immersion, TRH does not further activate the operating systems involved in the existing excessive grooming.

[Appendicitis in a personal 10-year patient sample]

862 patients underwent appendectomy for suspected acute appendicitis at the 3rd Surgical Department of the Semmelweis University, Budapest during the period from 1976-1985. In 111 cases neither the histologic examination nor the macroscopic finding at operation confirmed the inflammation. We considered these cases as "chronic appendicitis". The postoperative mortality rate was 0.8%. Surgical complications arose in altogether 10 patients. In the remaining 751 patients the mortality rate was 0.5% with 20 complications. The incidence of surgical complications was not significantly decreased in cases with "acute appendicitis" therefore we do not emphasize prophylactic appendectomy.

[Diagnostic significance of the detection of hepatitis B virus DNA in acute and chronic hepatitis]

1065 sera from patients with acute and chronic hepatitis-B-virus-(HBV-) infections, double infections (HBV, HAV, nonA-nonB, delta-Ag) as well as patients with HBs-Ag-negative hepatitis (HAV, nonA-nonB) and healthy subjects were investigated for the presence of hepatitis-B-virus-DNA using molecular hybridisation. The sensitivity of the method was 0.1 pg HBV-DNA/100 microliters. HBV-DNA could be detected in 62% of cases of HBs-Ag-positive sera with HBe-Ag, in 8.9% with anti-HBe and in 11% of e-marker free sera. In acute hepatitis HBV-DNA was present in 44%, in chronic hepatitis in 71% of HBe-Ag-positive sera. In HBs-Ag-negative sera containing only anti-HBc, HBV-DNA, depending on the anti-HBc-titre, was present in 13-24% of cases. HBV-DNA could not be detected in patients with HBV infections (anti-HBc and anti-HBs positive) in the past or in HBV-marker-negative hepatitis. Follow-up investigations on acute and chronic HBV-infections showed that the disappearance of HBV-DNA generally preceded the disappearance of HBe-antigen by about 2-3 weeks. In chronic hepatitis the time interval can amount to several months or years. Double infections with other hepatotropic viruses (nonA-nonB and delta-virus) can lead to a temporary suppression of HBV-DNA replication.

A clinical trial of three-part electronic differential white blood cell counts

Three-part white blood cell differential counts (diffs), performed during electrical impedance counting of blood cells, can accurately classify lymphocytes, granulocytes, and mononuclear cells in 85% of specimens, with an error rate not exceeding that of conventional diffs. To assess the clinical utility of the new test, we tried it for three months on a medical unit. Conventional diffs were no better than three-part diffs or total white blood cell counts in signaling clinical changes, and the same decisions would have been made in 78% of instances if only three-part diffs were available. The three-part diff is as reliable a clinical index for monitoring most inpatients as the conventional diff or white blood cell count. Although its use could effect significant cost savings, acceptance of the new test seems unlikely unless enforced by administrative flat.

Electric current flow in cell pairs isolated from adult rat hearts

Cell pairs were isolated from ventricles of adult rat hearts so as to study cell-to-cell coupling. Both cells of each pair were impaled with micro-electrodes connected to balanced bridge circuits. Rectangular current pulses were passed and the resulting voltage deflexions monitored. The data were analysed in terms of a delta configuration of three resistive elements, the resistances of the non-junctional membrane of cell 1 and cell 2 (rm, 1 and rm, 2), and the resistance of the nexal membrane (rn). The nexal membrane resistance was found to be insensitive to voltage gradients across the non-junctional membrane (range examined: -70 to -10 mV) and direction of current flow. The mean value of rn was 2.12 M omega ([K+]o = 12 mM). Taking into account morphological parameters, this corresponds to a specific nexal membrane resistance (Rn) of 0.1 omega cm2. Spontaneous uncoupling in which one cell remained polarized while the other one depolarized was never observed. The current-voltage relationship of the non-junctional membrane was found to be bell-shaped. The specific resistance (Rm) at the resting membrane potential (approximately -50 mV) was 3.2 k omega cm2 ([K+]o = 12 mM). Comparative studies performed on single cells revealed a similar relationship Rm versus Vm. Rm at the resting membrane potential (Vm approximately -50 mV) was 2.5 k omega cm2 ([K+]o = 12 mM). The specific capacitance of the non-junctional membrane (Cm) was determined from experiments on single cells. Cm was found to be independent of Vm (voltage range: -80 to 0 mV). The mean value of Cm was 1.66 microF/cm2 ([K+]o = 12 mM). For comparison, experiments on cell pairs and single cells were also carried out with [K+]o = 4 mM. The values obtained for Rn, Rm and Cm did not deviate significantly from those found with [K+]o = 12 mM.

Laboratory evaluation of the Coulter "three-part electronic differential"

Comparisons were made between "electronic" white blood cell (WBC) differential counts based on nuclear volume, differential counts performed by an automated image analyzer, and conventional manual counts performed by experienced technologists in a routine laboratory setting. The correlation between methods was excellent for lymphocytes (r = 0.9) and granulocytes (r = 0.9), but none of the three methods that were tested produced good results in enumeration of mononuclear cells (r = 0.6). Approximately 85% of the samples on which differentials were requested for an inpatient population could be processed by the electronic counter. Although the electronic counter failed to flag all abnormal samples (there were 6% false negatives), the performance of technologists doing 200 cell differentials was similar. Rapidly generated "electronic differentials" might be a useful and cost-effective adjunct to inpatient hospital practice if certain suggestions were implemented.

Virus-binding activity of fibronectin: masking of hepatitis A virus

Human plasma fibronectin interacts with viruses. When fibronectin-containing human sera negative for antibodies to hepatitis A virus (HAV) were added to suspensions of HAV, radioimmunological detection of HAV was reduced. This masking effect seemed to depend on the fibronectin concentration of the sera: plasma fibronectin purified by cryoprecipitation and affinity chromatography showed a masking effect on purified HAV which was dependent on the concentrations of fibronectin and HAV. Fibronectin peptides were obtained by subtilisin digestion: the non-collagen-binding regions of the fibronectin molecule were involved in the binding of HAV. We conclude that fibronectin has a virus-binding activity which interferes with radioimmunological methods for virus detection, and may contribute to the frequent transmission of hepatitis viruses by blood products enriched in fibronectin.

Electric current flow in a two-cell preparation from Chironomus salivary glands

Conventional micro-electrode techniques were used to study the passive electrical properties of salivary glands from Chironomus nuditarsis insect larvae of the fourth instar stage. Linear cable analysis performed on intact glands revealed the following constants: axial intracellular resistance, Ri = 2730 omega cm; membrane resistance per unit apparent cylindrical area, Rm = 1350 omega cm2; membrane capacitance per unit apparent cylindrical area, Cm = 17.6 microF cm-2. The multicellular glands were reduced to intact two-cell preparations by destroying neighbouring cells mechanically. Each cell of a coupled cell pair was impaled with two micro-electrodes, one to pass rectangular current pulses and the other to monitor the resulting voltage deflexions. Internal consistency tests revealed that the experimental data under steady-state conditions may be described accurately by an equivalent circuit consisting of a delta configuration of three resistive elements: the resistances of the non-junctional membrane of cell 1 and cell 2 (r1 and r2), and the resistance of the gap junctional membrane connecting the two cells (rg). The current-voltage relation of the non-junctional membrane was found ohmic over a membrane potential ranging from -40 mV to + 10 mV. The mean value of Rm was 2020 omega cm2. The resistance function of the gap junctional membrane was also ohmic. There was no dependence of gap junctional resistance on voltage or direction of current flow, at least over the relatively narrow range of potentials tested (approximately +/- 10 mV). Individual values of rg varied from 20 to 3800 k omega, with an over-all mean of 1100 k omega. The lower values are thought to represent the physiological state of cellular coupling, whereas the higher ones may reflect partial uncoupling caused by local damage. The proposed cell pair is a suitable preparation for studying problems related to intercellular coupling.

Free magnesium in sheep, ferret and frog striated muscle at rest measured with ion-selective micro-electrodes

1. Neutral carrier-based liquid membrane micro-electrodes were constructed which are suitable for continuous measurements of [Mg(2+)](i) in cardiac and skeletal muscle preparations.2. The electrodes show a Nernstian behaviour in pure MgCl(2) solutions. In the presence of a constant ionic background chosen to simulate the cytoplasmic composition, the calibration function flattens progressively with lower [Mg(2+)], due to the interference of K(+) and Na(+). The response to changes in [Mg(2+)] is less than 0.5 sec.3. In quiescent preparations at room temperature (23 degrees C), the following basal [Mg(2+)](i) were determined: 3.5 mM (sheep Purkinje fibres), 3.1 mM (sheep ventricular muscle), 3.0 mM (ferret ventricular muscle) and 3.3 mM (frog skeletal muscle).4. In cardiac tissue, electrical stimulation does not measurably affect the basal [Mg(2+)](i).5. In the presence of 0.5 mM-Mg(2+) (o), the calculated Mg(2+) equilibrium potentials, E(Mg), are in the range of -23 to -25 mV, suggesting that Mg(2+) is not passively distributed across the sarcolemma in striated muscle.6. Further studies were performed on sheep Purkinje fibres to investigate the effect of various experimental interventions on [Mg(2+)](i).7. Elevating [Mg(2+)](o) from 0.5 to 10 mM resulted in a reversible increase of [Mg(2+)](i). The initial rate of increase corresponds to a Mg(2+) influx of 0.42 p-mole/cm(2).sec, or a magnesium permeability, P(Mg), of 1.6 x 10(-8)cm/sec.8. Increasing P(CO) (2) from nominally 0 to 100 mmHg (Tris-buffered vs. bicarbonate-buffered Tyrode solution) produced a reversible decrease in [Mg(2+)](i) by roughly 0.45 mM, probably due to Mg(2+) binding the newly formed intracellular HCO(3) (-).9. The effect of metabolic poisoning on [Mg(2+)](i) was assessed by exposure to cyanide, iodoacetic acid and 2-4-dinitrophenol. No significant increase in [Mg(2+)](i) indicative of a liberation of Mg(2+) from ATP was observed.

Busulphan-induced chromosomal aberrations in intestinal cells of Chinese hamster

Chinese hamsters were given Busulphan, 25 and 50 mg/kg bw. After 18 h, chromosomes of the lining cells of the upper intestinal tract were prepared according to a newly developed method. The aberration rate was enhanced by a factor of about 25 after 25 mg/kg, but 50 mg/kg bw did not induce higher aberration rates. In the same animals the dose-dependent aberration rates were also determined in bone-marrow cells. Furthermore, the formation of SCEs in intestinal cells was observed. In a preliminary experiment, metaphase plates from intestinal cells of mice were prepared, too.

The rabbit during the last third of gestation. Data concerning the whole fetus, its diaphragm and brown adipose tissue

Total lipid, protein and glycogen concentrations were determined for the diaphragm and interscapular brown adipose tissue of fetal (22-31 days of gestation) and neonatal rabbits. In the diaphragm, protein concentration doubles and lipid concentration drops to half its initial value during the period under study; the glycogen level reaches its maximal value at 27 days, and decreases thereafter. In the brown fat, the lipid concentration rises steadily until the immediate prenatal period; the protein concentration remains steady and the glycogen is highest at 29 days of gestation. Fetal plasma glucose and insulin levels increase steadily; there exists a positive correlation between fetal plasma insulin levels and fetal body weight.

Incorporation of amino acids into protein of foetal rabbit diaphragm: effect of insulin

The incorporation of six L-amino acids into the protein fraction of the diaphragm of foetal and neonatal rabbits has been measured. Insulin stimulates the incorporation of lysine from the 29th day and of glycine from the 31st day of gestation onwards. The incorporation of histidine, serine and threonine is only enhanced in the diaphragm of 16-20 hour-old rabbits; no effect of insulin on the incorporation of leucine has been shown for the period under study.

Inhibitory effect of metyrapone on glucose utilization by brain and muscle and on insulin release by the pancreas

The effect of metyrapone on in vitro glucose metabolism in the rat muscle and brain, and on insulin secretion by the rat pancreas was investigated. In the presence of increasing concentrations of metyrapone ditartrate, there was a significant progressive reduction in glucose uptake by incubated hemidiaphragms and in the glucose uptake and oxidation by incubated brain pieces. The insulin output by incubated pieces of pancreas was also significantly inhibited by metyrapone ditartrate. A clear dose-action relationship is shown between the residual glucose uptake by the muscle and the uptake or oxidation of glucose by the brain on one hand, and the logarithm of the corresponding metyrapone ditartrate concentration on the other.

These data may help to explain some clinical and experimental findings, i. e. the simultaneous occurrence of hyperglycaemia, signs of cerebral dysfunction and also of growth hormone release after the administration of metyrapone in vivo.