Evolution of the immunodominant domain of the circumsporozoite protein gene from Plasmodium vivax. Implications for vaccines

Recent work directed toward the development of a malarial vaccine has focused on the identification and production of the immunodominant repeating peptide of the circumsporozoite protein of the human malaria parasites as an antigen. An important factor which relates to the usefulness of this antigen in a vaccine is the rate at which the molecule changes in sequence. We have determined the sequence and arrangement of the repeating epitope of the circumsporozoite protein gene from a Plasmodium vivax isolate from La Paz, El Salvador (Sal-I). This is compared with a portion of the previously published sequence of the circumsporozoite protein gene from a P. vivax isolate from Belém, Brazil. The genes appear to be very similar in the repeat region. There are 20 similar repeating units in the El Salvador strain and only 19 units are conserved in the Brazilian strain. Following this there are degenerate repeats in both strains. Even the pattern of silent mutations in the repeat area are similar; however, they are not necessarily in the identical location and appear to have shifted. The data suggest that the repeat region of these genes may be evolving by an accelerated mechanism(s). Such a phenomenon could severely decrease the long-term efficacy of a repeat-based anti-sporozoite vaccine.     

Developmental and Dimensional Changes in the Cambial Fusiform Initials ofHoloptelea integrifolia (Roxb.) Planch.

Divisional activity, intrusive growth of the cell wall and loss of fusiform initials have been studied in Holoptelea integrifolia. The dimensional changes in relation to mean length, length frequency, mean width and length variation in relation to fibre length have also been analysed.     

24-hour profiles of blood pressure and heart rate in Cushing's syndrome: relationship between cortisol and cardiovascular rhythmicities

We monitored the circadian profiles of cortisol, systolic and diastolic blood pressure (SBP and DBP) and heart rate (HR) in 33 matched normotensive subjects, 32 patients with essential hypertension and 16 patients with Cushing's Syndrome (8 pituitary adenomas, 6 adrenal adenomas and 2 adrenal carcinomas). Each subject underwent serial blood drawings at 4-hr intervals along the 24-hr cycle. BP and HR were automatically recorded every 30 min. Data were analyzed by conventional statistics and by chronobiological procedures (cosinor rhythmometry). Both the control subjects and essential hypertensives showed a circadian profile of BP and HR characterized by a peak in the early afternoon and a clear nocturnal fall (rhythm detection: P less than 0.001). The rhythmicity of BP was disrupted in patients affected by Cushing's Syndrome, whereas the 24-hr oscillation of HR was preserved (P less than 0.001). Our data are compatible with the view that glucocorticoids are involved in the control of BP circadian rhythm, whereas HR is not under their control.     

A genetic linkage map of chromosome 17

We have developed a genetic linkage map of 19 markers (including nine genes) on human chromosome 17, providing 13 reference points along virtually the entire length of this chromosome. The map covers an estimated 149 cM in length (sex-averaged), with a total length of 214 cM in females and 95 cM in males. This sex difference appears to be significant along virtually the entire length of the map. This map will be useful both for providing reference points for fine structure genetic and physical mapping and for genetic linkage studies of diseases, including von Recklinghausen neurofibromatosis and Charcot-Marie-Tooth disease.     

Melatonin and human cancer

A number of studies performed in vitro and on experimental animals supported the view that pineal gland inhibits neoplastic growth. Data in humans are scanty and controversial. In the present study we measured serum melatonin (MT), prolactin (PRL) and growth hormone (GH) concentrations, at 08.00 and 24.00, in 132 cancer patients and in 58 healthy control subjects. The patients were stratified according to histology and stage of disease as follows: 30 stage I–II and 45 stage III–IV breast cancer (BC); 39 stage III–IV lung cancer; 18 advanced gastrointestinal (GI) cancer. We also measured MT levels, at the same time-points, in 20 women with primary BC before and after radical mastectomy. Finally, we evaluated the circadian rhythm of serum MT in 18 patients with advanced cancer. On the whole, the patients with advanced tumors showed serum MT levels significantly higher than controls, without any correlation with PRL and GH values. When looking at stage III–IV vs stage I–II BC patients, significantly higher MT levels have been found in the former group. The surgical removal of the primary BC was not associated with any changes in MT values at both time points considered. A highly significant rhythm of serum MT was recorded in advanced cancer patients and the rhythmic parameters were substantially superimposable on those of the control subjects.