Nelson Marques

Latitude and Social Habits as Determinants of the Distribution of Morning and Evening Types in Brazil

Previous application of a Portuguese version of the Horne and Ostberg (H&O) questionnaires in Brazil showed a displacement of the distribution of Morningness/Eveningness (M/E) types towards morningness, demanding a reclassification of the scores limits for each of the 5 possible M/E types. Among city, age and sex, city was the only factor determining significant group differences. In the present paper, the same version of the H&Os questionnaire was applied to a distinct population of 260 adults, balanced according to age, sex and city. Data were collected from October to December, to control the effect of the photoperiod. City remains the only factor determining significant group differences (p <0.001). Moreover, there does not appear a coherent latitude trend that could explain differences among cities as a function of photoperiod. Local social habits could probably explain our results, suggesting further investigations of peculiar temporal patterns.

Extraction and characteristics of a nuclear rapidly labelled RNA fraction from Rhynchosciara salivary glands

Abstract A DNA-like RNA fraction was obtained by extracting at high temperature the interphase remaining after treatment of Rhynchosciara salivary glands with phenol in the cold, at neutral and slightly alkaline conditions. This RNA is mainly of nuclear origin but most of it is not bound to chromatin. Several other characteristics of this RNA fraction are also described.

Circadian Rhythm of the Endopeptidase 22.19 (EC 3.4.22.19) in the Rat Brain

The endopeptidase 22.19 (EC 3.4.22.19) has been associated with the metabolism of neuropeptides by its ability to convert small enkephalin-containing peptides (8 to 13 amino acids) into enkephalins. In addition, this enzyme cleaves the Arg8-Arg9 bond of neurotensin and the Phe5-Ser6 bond of bradykinin. We analyzed the circadian variation of endopeptidase 22.19 in the whole and individual areas of the rat brain. Endopeptidase 22.19 activity was analyzed by high-performance liquid chromatography (HPLC) using bradykinin as an operative substrate. Enzymatic specific activities were analyzed by rhythmometric methods and indicate a circadian fluctuation of endopeptidase 22.19 specific activity (mU of enzyme/mg of protein) in the whole brain [p less than 0.001, mesor (M) = 7.62, amplitude (A) = 2.89, and acrophase (phi) = 23:08 h], striatum (p less than 0.001, M = 2.92, A = 0.62, phi = 23:03 h), hypothalamus (p less than 0.001, M = 3.15, A = 0.86, phi = 01:12 h), periaqueductal gray matter (p less than 0.005, M = 2.62, A = 0.34, phi = 22:35 h), and cerebellum (p less than 0.014, M = 4.27, A = 0.88, phi = 17:12 h). The circadian rhythmicity in endopeptidase 22.19 specific activity suggests that light may have an effect on the peptidase activity in whole brain and in areas of the central nervous system and may be essential for the mechanisms of circadian fluctuations of neuropeptides in the brain.

Population studies of ambulatory blood pressure monitoring in Brazilian children

BACKGROUND The determination of hypertension in a given population depends on the knowledge of population norms for blood pressure. This is true for both casual blood pressure (CBP) measurements and the newest and most promising technology of ambulatory blood pressure monitoring (ABPM). OBJECTIVE To design an ambitious multinational co-operative study to determine normal blood pressure data in Brazilian children. METHODS The study was designed to determine normative data for CBP, using the Task Force technical recommendations for age-, sex- and height-percentile-specific blood pressure values. The proposed procedure is as follows. ABPM will be studied in a random subgroup of individuals, to develop similar normative data. These data will be correlated to CBP measurements and to echocardiographic findings as a measure of end-organ damage. All patients who are diagnosed by CBP measurement to be hypertensive will also be studied by ABPM, and studies of target-organ damage will be performed. Family and medical histories will be evaluated by questionnaire and first-degree relatives will be evaluated for CBP measurement. Hypertensive patients will form a cohort for long-term follow-up. These data will be the foundation for studies of hypertension in Brazilian children.

Independence between Rhythms of Temperature and Progesterone in Mares

We investigated the ultradian and diurnal body temperature and plasma progesterone concentration rhythms and the temporal relationship between them in mares during the midluteal phase. Data were obtained from 6 mares at 3-h intervals for 3 consecutive days. Cosinor analysis showed that body temperature acrophases occurred in the evening, whereas the progesterone acrophases occurred in the early morning (3 mares) and at night (3 mares). The spectral analysis of the temperature data showed periods of 24 hr for all mares and of 8 hr for 1 mare. In contrast, the periods observed for plasma progesterone concentration were quite divergent (24 and 12 hr). The small variation in the rhythmic parameters of body temperature suggests that its oscillator system is stable. No phase relationship was detected between the rhythmometric parameters of body temperature and plasma progesterone concentration, suggesting that the physiological mechanisms of control of the 24 hr and ultradian rhythm of the two variables are not coupled during the midluteal phase.

Building a Coherent Time Series with Behavioral Data from Staggered Chambers

Sampling of population with the design of staggered chambers is quite convenient, since it allows data collection from distinct time points at the same clock hour. In this short communication using an ethological approach we report results obtained with behavioral data collected from eight staggered chambers. The eight LD cycles (12:12; L = 350 lux; D = 1 lux, red light) were set with a lag of 3 h, thus completing 24 h. Male Wistar rats 6-month old were individually observed for five minutes in random order within each session along ten consecutive days. Behavioral circadian rhythms of general activity were detected both in the 10-day long time series and in each one of the days, with a statistical significance of 95%. Our results show close similarities with results of individual days, thus pointing to the convenience of such a design.

Reiteration frequency of procollagen genes in the guinea pig genome. Collagen genes are not amplified during granuloma fibroblasts differentiation.

Procollagen mRNA was purified from collagen synthesizing polysomes obtained from an experimental guinea pig granuloma, and iodinated in vitro. The procollagen 125I-labelled mRNA was hibridized with granuloma and liver guinea pig DNA in vast DNA excess conditions. A Cot 1/2 800-900 mol . s . 1-1 for both tissues was obtained from the hybridization curves. With these results, we could suggest the existence of 11-13 procollagen genes per haploid genome. By the analysis of the hybridization data it was possible to infer that there is no genomic amplification in tissues highly specialized in the synthesis of collagen such as granuloma.