Visualization of epidermal growth factor receptor in cryosections of cultured A431 cells by immuno-gold labeling

Cryo-ultramicrotomy in combination with immuno-gold labeling has been demonstrated to present a powerful tool in the visualization of extra- and intracellular located antigens. We have applied this method to localize epidermal growth factor (EGF) receptor in cultured A431 human epidermoid carcinoma cells. However, both the labeling efficiency, maintenance of antigenicity, and the recognizability of the ultrastructure in cryosections are highly dependent upon the fixation procedures. Using 125I-EGF or a consecutive labeling with a monoclonal anti EGF-receptor antibody, rabbit-anti-mouse antibody and 125I-protein A, it was shown that maintenance of antigenicity was optimal using 2% paraformaldehyde as a fixative, whereas under these conditions also the recognizability of ultrastructure was sufficient. After appropriate fixation and labeling, gold particles were observed associated with various regions of the plasma membrane, including coated pits, and with various types of vesicles, including coated vesicles, intracellular vesicular membranes, multi-vesicular bodies and lysosomes. The results indicate that this method allows a visualization of EGF-receptors and resolution of the EGF-receptor processing pathway at the electron microscopic level, independent of the internalization process of labeled ligands.     

Disturbances in toxicological experiments caused by Microsporum canis

Cutaneous lesions which can lead to false positive results have been observed in several rabbits used for the determination of the cutaneous irritation capacity of a product (ITA, PII). The responsible agent was Microsporum canis. A preventive treatment by an antifungal agent did not modify toxicological experimental results.     

Morbidity in Chagas' disease. IV. Longitudinal study of 10 years in Pains and Iguatama, Minas Gerais, Brazil

An evolutive study of the "case-control" type was carried out in an endemic area of Chagas' disease in Minas Gerais State, Brazil, using two cross-section evaluations with an interval of ten years between them (1974-1984). Patients were paired for sex and age. In the first cross-section study 264 pairs one with a positive serology and the other with a negative serology for T. cruzi antibodies were included. In the second evaluation, ten years later, 235 patients among those with previous positive serology and 216 with negative serology were located, but only 110 pairs could be recomposed and reexamined (clinical examination, ECG and Rx of the heart and esophagus). The incidence of chagasic cardiopathy in the cases with positive serology but previously assymptomatic was 38.3% during the ten year period. On the other hand there was a deterioration in 24% of the patients with chagasic cardiopathy since the first examination. Considering all clinical forms of the disease in 34.5% of the patients the clinical situation deteriorated, in 57.3% there was no change and in 8.2% the situation improved. The general mortality in the period was 23% in the chagasic group and 10.6% in the control group, but the lethality by cardiopathy was 17% in chagasic group and only 23.3% in the control group. The mortality was twice as high in males than in females, mainly in the age group from 30 to 59 years.     

Isolation and characterization of Pediococcus halophilus from salted anchovies (Engraulis anchoita)

The presence of bacteria in salted anchovies during and at the end of the curing process was investigated. Attempts to isolate bacteria under aerobic or anaerobic conditions led to the isolation of only bacteria of the genus Pediococcus which were identified as Pediococcus halophilus. The isolates correspond to a rather heterogeneous group in which some of the members differ in some biochemical tests from the types described in the literature.     

No narcosis for bone marrow harvest in autologous bone marrow transplantation

A prospective study with mild general analgesia and sedation together with local anesthesia during bone marrow harvest was performed. Thirty-one patients underwent 33 bone marrow collections. Pretreatment consisted of 100 mg meperidine i.m. and 20 mg diazepam i.m. 1 h before start of procedure. Eight patients got additional meperidine and diazepam during the procedure, all patients got lidocaine 1% locally. A mean volume of 1.321 was obtained with 42.5 punctures. Twenty-two patients had no complications, 4 vomited, 4 had easily correctable hypotension of short duration, one got oxygen for cyanosis of short duration. Acceptance was good in 23 patients, in 6 reasonably well, in two bad. Only one patient experienced pain problems, due to suction. Anxiety was no major problem due to good information before the procedure and mild sedation. This form of anesthesia for bone marrow collection is a safe procedure, it is generally well accepted by the patient and it can be performed on an out-patient basis.     

Release of dopamine, noradrenaline and dopamine B-hydroxylase from mouse neuroblastoma

The murine C1300 neuroblastoma tumor was found to secrete dopamine, noradrenaline and dopamine B-hydroxylase into the circulation of tumor-bearing A/J mice. The plasma levels of dopamine, noradrenaline and dopamine B-hydroxylase increased with the size of the tumor, and the increase in noradrenaline paralleled the increase in dopamine B-hydroxylase (r = 0.86). The vesicular storage of dopamine and noradrenaline in the tumor was evidenced by a decrease of the tissue content of dopamine and noradrenaline 24 hours after the administration of reserpine (5 micrograms/g) respectively to 17.6% and 7.8% of control values. A similar observation could be made for the levels of dopamine and noradrenaline in the plasma of reserpinized C1300 mice. The total activity of dopamine B-hydroxylase in the tumor and in plasma was unaffected by the reserpine treatment. Chronic administration of 6-hydroxydopamine (100 micrograms/g for 8 days) had no effect on the tissue contents of dopamine, noradrenaline or dopamine B-hydroxylase. The release of catecholamines and dopamine B-hydroxylase from the C1300 neuroblastoma was studied in vitro on superfused tumor slices. Stimulation of these slices with 56 mM KC1 or with 5.10(-5) M tyramine failed to induce the release of endogenous dopamine, noradrenaline or dopamine B-hydroxylase above the basal outflow levels. These results are suggestive for a non-exocytotic release of catecholamines and dopamine B-hydroxylase from the neuroblastoma tumor.     

The occurrence of Cryptocoryne and Lagenandra (Araceae) on Sri Lanka

Depending on the species, Cryptocoryne plants grow in different biotopes, viz. spring, river, dark forest, and tree-savanna. The species of Lagenandra are exclusively found in river biotopes. The chromosome numbers found in this study corroborate the numbers previously recorded. Some variation in respect to the morphology of the inflorescence of C. wendtii de Wit and L. ovata (L.) Thwaites is described. A map presenting the distribution of the of Cryptocoryne with their chromosome numbers is included.
The existing populations of Cryptocoryne on Sri Lanka should be protected from further exploitation by plant collectors.