The Colchicine Method in the Study of Bone Marrow Cell Proliferation

The rate of metaphase accumulation in the bone marrow cells of AKR micetreated with colchicine was investigated. The influence of this alkaloid onthe differential count of the bone marrow cells in these animals was alsostudied. It was demonstrated that the stathmokinetic effect of colchicine onthe bone marrow cells started almost immediately after the administration ofthe drug. The number of arrested metaphases increased linearly from one-halfhour to six hours after the injection of colchicine, and then fell rapidly.

In rats injected with colchicine, the changes in the bone marrow concentration of this compound were followed for eight hours. The colchicine concentrations increased from the first to the fourth hour, and then fell rapidly, reachingthe zero level at the eighth hour.

From the results obtained, it appeared that four hours post-injection wasthe most convenient time for the study of the bone marrow proliferative activity by the colchicine method when 1.2 mg./Kg. of colchicine per body weightwas used. The fact that four hours after the injection, a mild decrease in thepercentage of mature bone marrow granulocytes was found, may represent alimiting factor, which is, however, of moderate importance in the application ofthis technic.

Submitted on May 5, 1961 Accepted on June 14, 1961     

The effect of glycerol on the guinea-pig hydropic ear

The aim of this paper was to investigate the effect of glycerol on experimental endolymphatic hydrops in guinea-pigs. The right endolymphatic sac and duct were obliterated through an extradural posterior fossa approach. Some animals received a 3 g/kg dose of glycerol for a period of 7 days, whereas others received the same dose for 30 days. The activity of glycerol was studied by investigating the volumetric changes in the scala media determined with a computerized planimeter. Glycerol induced a significant reduction of the hydrops showing its effectiveness and suggesting a strial metabolic response.     

Zinc and Vitamin A in Liver of Foetuses and Infants

ABSTRACT. The association of zinc and vitamin A levels was studied in liver of foetuses and infants which were stillborn or died of various causes between the age of 26 weeks of gestation up to 16 weeks post-partum. No correlation between zinc and vitamin A was observed ( r =0.07). Although smaller infants had more hepatic vitamin A than larger infants no significant difference was observed between these groups for liver zinc values.     

Follow-up of the Antibody Response to Measles Vaccine in a Rural Area of Guinea-Bissau

ABSTRACT. One hundred and fourty-four children who either were already immune or had been successfully immunized against measles were reexamined after 16 months. All still had circulating Elisa antibodies at a clearly detectable level. Titres were higher in the group of children stated to have had measles prior to the immunization. None of the children had measles after immunization. Boostering by the wild virus may have occurred, whereas no evidence of a booster effect from the vaccine was found. About one third of the children were underweight. Plasmodium falciparum parasitaemia rate, and also its seasonality, varied with the location of the child's homestead. Even children exposed to mesoendemic P. falciparum malaria and moderate malnutrition can be successfully immunized with a conventional live attenuated measles vaccine from 8 months of age, which probably results in a lasting protection.     

Influence of Age, Lead Axis, Frequency of Arrhythmic Episodes, and Atrial Dimensions on P Wave Triggered SAECG in Patients with Lone Paroxysmal Atrial Fibrillation

Signal-averaged P wave of 42 patients with lone paroxysmal atrial fibrillation (PAF) and 29 normal subjects (N) were recorded, using three orthogonal leads and analyzed in the time and frequency (entire P wave or a 100-ms segment ranging from 75 ms before to 25 ms after the end of P wave) domains. PAFs were divided into a group of 12 having ≥ 2 attacks a month (HF) and a group of 30 having ≤ 2 attacks a year (LF). Statistically significant differences were absent with regard to ages of PAF and N; ages of HF, LF, and N at the time of signal-averaged ECG; ages of HF and LF at the time of the first arrhythmic episode; and elapsed times from the first episode. Length of P wave and some frequency-domain parameters were found to be significantly correlated with age. PAF showed a significantly longer duration of P wave in the frontal plane using the time-domain analysis. Frequency analysis was found to be useful in evaluating the influence of attack frequency. HF showed significantly higher values of some frequency-domain parameters than LF and N, while the three groups did not differ for time-domain analysis. P wave duration and frequency content of the three orthogonal leads proved to be significantly different in PAF and N. Right and left atrial echocardiographic dimensions proved to be higher (even if within normal limits) in HF than in LF and N. Results suggest that frequency analysis should be performed on the entire P wave.     

EFFECTS OF HYPERTONIC SOLUTIONS AND OF MERCURIC CHLORIDE ON THE UPTAKE OF [14C]GLUCOSE ANALOGUES BY RABBIT BRAIN

Intracarotid perfusion of hypertonic solutions of urea, NaCl or acetamide increased the brain uptake index (BUI) of glucose analogues by rabbit brain, while isotonic urea was without effect. Lactamide, whether isotonic or hypertonic, decreased the BUI of glucose analogues. The increased BUI produced by the other hypertonic solutions could be inhibited by unlabeled substrate, unlabeled glucose or by phloridzin, and may reflect stimulated carrier-mediated transport of monosaccharides into brain. Although the increases could also have been due to altered cerebral blood flow, radioautography showed no gross evidence of such alterations. The BUI of 2-2-deoxy-D-[1-¹⁴C]glucose was decreased by intracarotid injection of 0.01mM HgCl₂, to the same level seen following maximal inhibition with unlabeled 2-deoxy-D-glucose, while 0.08mM HgCl₂ gave BUI's above this level. The lower concentration of HgCl₂ probably inhibited carrier-mediated monosaccharide transfer, while the higher concentration appeared to increase passive diffusion into the brain as well.     

GROWTH HORMONE (GH) SECRETION IN HEPATIC ENCEPHALOPATHY

Elevated plasma concentrations and abnormal secretory patterns of GH have been found in patients with cirrhosis of the liver. Displacement of brain dopaminergic monoamines by false ‘neurotransmitters’ produced in the gut has been postulated as a cause of encephalopathy. In this study basal GH plasma levels and their response to TRH and l -DOPA were determined in thirty-nine cirrhotic patients and fifteen controls. Eleven patients had evidence of encephalopathy (Group 1), twenty-eight did not (Group 2). Both basal levels and the mean peak response to TRH were significantly higher in the cirrhotic patients than in the controls (Group 3). Peak values were moderately, but not significantly, higher in Group 1 than in Group 2. The response to l -DOPA was considerably lower in the encephalopathic patients in comparison with the subjects of both Group 2 and Group 3. This finding is consistent with depletion of active ‘neurotransmitters’ in CNS. Our data fail to demonstrate clearly whether the paradoxical response to TRH can also be related to these abnormalities of monoamine metabolism in cirrhotics.