Decreased sensitivity to phalloidin of aged F344/DuCrj rat hepatocytes

The phalloidin sensitivity of hepatocytes resulting in the formation of cytoplasmic blebs was examined with cells isolated from 73- to 74-week-old and 99- to 100-week-old F344/DuCrj rats of both sexes by a collagenase perfusion method. The cells isolated from aged rats were less sensitive to the toxin than those obtained from 10- to 14-week-old rats. The decrease in the sensitivity was more marked in males than in females, and it appeared at an earlier age in the former than in the latter. Phalloidin consumption experiments showed decreases in the cellular uptake of the toxin in aged rats, and these were more marked in males than in females. The low cellular uptake of the toxin seemed to play an important role in the low sensitivity of the cells in aged rats. Although histological and histochemical examinations showed the development of foci of altered hepatocytes in the aged rat liver, the foci were estimated to account for less than 1.5% of liver tissues. Thus, the decrease in the sensitivity of the cells isolated from whole liver tissues might mainly be attributed to the decrease in the sensitivity of otherwise normal-looking hepatocytes.     

Characterization of hindlimb motoneuron membrane properties in acute and chronic spinal cats

The purpose of this study was to determine if changes in hindlimb motoneuron membrane electrical properties occur 4–6 months after spinal transection in the adult animal. Eight acute and nine chronic animals were spinalized at T₁₂. Intracellular recordings from motoneurons innervating the triceps surae were performed. Membrane electrical properties, including resting potential, action potential peak amplitude, afterhyperpolarization duration, rheobasic current, input resistance and axonal conduction velocity were measured. There were no statistical differences found between group means or frequency distributions in the membrane properties of motoneurons assessed from acute and chronic spinal animals. Thus, alteration of motoneuron membrane properties does not appear to be a major contributing factor to the hyperexcitable hindlimb reflex activity demonstrated by chronic spinal animals.     

Myeloid regeneration after bone-marrow transplantation monitored by serum measurements of myeloperoxidase, lysozyme and lactoferrin

Bone-marrow regeneration after chemo- and radiotherapy-induced aplasia can be monitored by serum levels of myeloperoxidase (MPO), lysozyme (LYS) and lactoferrin (LF). In 10 patients with leukemia, serum measurements were performed before and after bone-marrow transplantation. Bone-marrow regeneration was suggested by increments in serum MPO and LYS 5 and 4 days prior to the increase in mononuclear cells (Mono) and 10 and 9 d before the increase in polymorphonuclear leukocytes (PMN) in the peripheral blood. LF started to rise 4.5 d before detectable circulating PMNs. 2 patients with early relapses of leukemia post transplantation are shown to display atypical patterns of serum MPO and LYS. We conclude that serum measurements of MPO, LYS and LF may be used as early and sensitive means to monitor bone-marrow activity during hematological regeneration. However, the findings also strongly support the earlier proposal that MPO alone may be used to reflect myeloid activity in the bone-marrow in general.     

Significance of coupling intervals of spontaneous ventricular arrhythmias in long-term ECG in patients with coronary heart disease

Coupling intervals of premature ventricular beats and complex arrhythmias were studied by 24-h ambulatory electrocardiographic recordings in 76 patients (35 sudden death patients and 41 survivors) with coronary artery disease. A first Holter (HM 1) was recorded at the time of left ventricular angiography and a second Holter (HM 2) after a mean interval of 34.4 +/- 11.2 months (range 2-61 months). All patients were only treated medically. The mean heart rate was significantly faster in patients who died suddenly than in survivors in both HM 1 and HM 2 (p less than 0.01). In HM 1, there were no significant differences in mean coupling intervals between patients who died suddenly and survivors, whereas in HM 2, coupling intervals of premature ventricular beats and couplets were significantly shorter in patients who died suddenly than in survivors (p less than 0.05). Patients with coupling intervals for couplets less than 500 ms died significantly earlier than those patients with coupling intervals greater than 500 ms (p less than 0.05). Our data show that there is a relationship between heart rate, coupling intervals and sudden death. Patients with fast heart rates and coupling intervals for couplets less than 500 ms represent a group at high risk of sudden death.     

Fate of TR-2, the hepatic metabolite of the tremorgenic mycotoxin verruculogen, in sheep

1. Verruculogen is eliminated in bile after transformation to TR-2, only a trace of which was excreted as such in faeces of sheep given verruculogen per os. Negligible TR-2 was present free in urine; no glucuronide was found. 2. An isomer of TR-2, a minor component of the bile of sheep given verruculogen, has been defined by 1H-n.m.r. spectroscopy and the isomerism involves the disposition of the two adjacent hydroxyl groups with a concomitant change in the conformation of the ring adjacent to the indole. 3. 14C-TR-2, added to the perfusate of isolated rat liver, was excreted unchanged in the bile, implying no significant loss of any biliary TR-2 subject to enterohepatic recycling in vivo. 4. 14C-TR-2 incubated anaerobically in sheep ileum contents was 95% transformed into more polar metabolites, the majority of the radiolabelled metabolites isolated being water soluble. 5. The principal fate of biliary TR-2 is as a metabolic substrate for the intestinal microflora.     

Identification of testicular atypical germ cells by an immunohistochemical technique for placental alkaline phosphatase

The identification of atypical testicular germ cells is often difficult by by routine histologic examination. By immunohistochemical detection of placental alkaline phosphatase (PLAP) and by periodic acid Schiff staining of glycogen, atypical germ cells were easily identified in testicular samples. Forty-one fetal and adult testes were used for a preliminary study, and 121 testes from infants and adults with either cryptorchidism or germ cell tumors were studied for the presence of atypical germ cells. Two types of clear germ cells were differentiated histochemically, and one with PLAP-positive cell surfaces and glycogen-rich cytoplasm was considered to be atypical. The alkaline phosphatase of atypical germ cells appeared to be similar to that found in a few germ cells of early fetal testes. The atypical germ cells seemed to be multi-potential malignant cells capable of developing not only into seminoma but also into other germ cell tumors. Only in yolk sac tumor of infants were the atypical germ cells absent from tumor-adjacent seminiferous tubules.     

Ethanol and liver injury: aspects relating to hepatic protein synthesis

Throughout the world ethanol consumption is probably one of the most important and widespread environmental factors in inducing human liver disease. Although it has been established that ethanol is a potent hepatotoxic agent, the mechanism/s by which it acts upon the liver is/are not clear. This review focuses upon one aspect of ethanol and its effect on liver metabolism, that relating to hepatic protein synthesis. Experimental studies have been reviewed and the current views regarding the action of ethanol upon hepatic protein synthesis are presented. The overall picture still remains to be clarified.