Circannual Incidence of Giardia Lamblia

A circannual rhythm of Giardia lamblia positive stools was found by examination of records from three clinical laboratories in central Arkansas for the period 1980-1986. Cosinor analysis of monthly Giardia incidence based on stool specimen records from approximately 12,000 patients over the 7-year period revealed a circannual rhythm (P< 0.001) on the basis of percent positive patients/month, with a computive acrophase occurring in late summer and minimum values in the winter. Patients involved in the study were primarily from the central Arkansas metropolitan areas, southern delta regions and northern mountainous regions of the state. Analysis of the data on the basis of total positive Giardia patients/month also revealed a circannual rhythm with the acrophase again occurring in late summer. The overall mean for percent positive stool specimens for the 7-year period was 5.3%, compared with the national average of 3.8% for G. lamblia positive stools. The data indicate that there may be a “Giardia season” in Arkansas since they could not be explained on the basis of day-care age distribution, or geographic origin. Awareness by epidemiologists, public health officials and other health care professionals of this circannual incidence of giardiasis is important for the prevention, diagnosis and treatment of this infectious disorder.     

Circannual Variations of the Bleeding Time in the Rat

This study was carried out to determine the annual fluctuations of the tail bleeding time in the rat. Bleeding time was determined by transection of the tail of pentobarbital-anesthetized rats. Over a 6-year period, monthly measurement of the tail bleeding time revealed highly reproducible circannual fluctuations. Bleeding times were shortened in the summer (414 ± 18 s in July), being almost half that observed during the winter span (886 ± 32 s in January). The difference between these two time points was highly significant (p > 0.001). This study reports for the first time circannual variations of the bleeding time in the rat.     

Glycerolipid Acyl Hydrolase Activity in the Brown Alga Cladosiphon okamuranus TOKIDA

The brown alga, Cladosiphon okamuranus TOKIDA, was found to contain a large amount of free fatty acid (45% of the total lipids). A crude enzyme preparation from the alga showed activity for hydrolyzing the acyl groups of various glycerolipids. The results suggest that the free fatty acid in C. okamuranus was released mainly from glycoglycerolipids, which were the major lipid components in the alga, by such glycerolipid acyl hydrolases as galactolipase.     

Circannual Rhythm of Insulin Release and Hypoglycemic Effect of Tolbutamide Stimulus in Healthy Man

Four healthy non obese young volunteers were observed for a 24-hr period, every other month, over the course of one year. Tolbutamide was injected i.v. each day of the experiment every four hours. Tolbutamide-induced insulin secretion (T.I.I.S.) was evaluated by planimetrically measuring insulin areas above basal levels. Tolbutamide-induced hypoglycemic effect was evaluated by measuring the blood glucose difference between the Sth and 25th minute after the drug injection (δG 5′-25′). The macroscopic evaluation of T.I.I.S. and δG 5′-2S′(mean chronograms) permitted the detection of the existence of a circannual variation of both variables. In particular the maximum level of the blood glucose drop (δG 5-25) was registered in February.

Subsequently the quantification of the rhythm of T.I.I.S. was obtained by fitting a sine curve, according to the Cosinor method. The highest insulin release was confirmed in winter.

As previously documented, the existence of a statistically significant circadian rhythm of T.I.I.S. was confirmed in the morning, i.e. the same period of the day in which insulin-induced hypoglycemia occurs.     

Pinealectomy and LL Abolished Circadian Perching Rhythms but Did Not Alter Circannual Reproductive or Fattening Rhythms in Finches

In the subtropical finch, spotted munia (Lonchura punctulata) circannual rhythms (of gonads, fattening, feeding) have been demonstrated in an information-free environment of continuous illumination (LL), rendering it an ideal model for research on the physiology of the circannual clock. In an attempt to understand the involvement, if any, of the circadian system in the genesis of circannual rhythms, we studied the effect of pinealectomy (LL 15 lux) and strong continuous illumination (LL 300 lux), both known to abolish circadian rhythms, on the circadian perch-hopping rhythm and on the circannual rhythm of reproduction and fattening in the same birds. While both pinealectomy and LL 300 lux treatments abolished the circadian rhythm of motor activity, they had no effect on the circannual rhythms of gonadal size and fattening. If the endogenous circadian rhythm in perch-hopping can be taken to reflect the circadian clock mechanism associated with gonadal functioning, present results suggest that circannual rhythm of reproduction in spotted munia is independent of circadian events.     

Pinealectomy and LL Abolished Circadian Perching Rhythms but Did Not Alter Circannual Reproductive or Fattening Rhythms in Finches

In the subtropical finch, spotted munia (Lonchura punctulata) circannual rhythms (of gonads, fattening, feeding) have been demonstrated in an information-free environment of continuous illumination (LL), rendering it an ideal model for research on the physiology of the circannual clock. In an attempt to understand the involvement, if any, of the circadian system in the genesis of circannual rhythms, we studied the effect of pinealectomy (LL 15 lux) and strong continuous illumination (LL 300 lux), both known to abolish circadian rhythms, on the circadian perch-hopping rhythm and on the circannual rhythm of reproduction and fattening in the same birds. While both pinealectomy and LL 300 lux treatments abolished the circadian rhythm of motor activity, they had no effect on the circannual rhythms of gonadal size and fattening. If the endogenous circadian rhythm in perch-hopping can be taken to reflect the circadian clock mechanism associated with gonadal functioning, present results suggest that circannual rhythm of reproduction in spotted munia is independent of circadian events.     

Circannual Variation in the Incidence of Uterine Cervix Cancer

The impact of uterine cervix cancer (UCC) can be greatly reduced by regular vaginal examination and other preventive measures. With this aim, UCC screening programs had been developed and applied for several years in Mexico and elsewhere. One point still to be considered in such preventive programs is the possible circannual pattern in the morbidity or mortality of UCC. With the aim of identifying a possible circannual pattern of variation in the incidence of UCC, we analyzed the monthly totals of positive detected cases of UCC in the state of Nuevo León (Mexico) between 1978 and 1987. For eliminating bias due to the seasonal variation in the number of preventive check-ups, data were first expressed in percentage of tests done in the same month. The least-squares fit of a 1 -year cosine curve to the data reveals a statistically significant circannual pattern (p = 0.013), with a maximum of relative incidence detected in February. Results indicate UCC incidence higher than the yearly average during the winter, with secondary peaks in August and November. This pattern of variation is similar if one considers separately for analysis the relative incidence of type III, IV, or V UCC (relating to cases suggesting, highly suggesting, or concluding a malignant alteration, respectively). For evaluating the cost-effectiveness of the UCC screening campaign providing these data, the monthly totals of screening check-ups done over the same period were also analyzed. Results reveal a statistically significant circannual rhythm (p > 0.001), with a maximum detected in June. This timing seems to be related to the incidence of most common diseases in Mexico, such as giardiasis and salmonellosis, but not to the UCC morbidity rates. Health educational and screening campaigns for prevention of UCC and other major conditions should be timed during the year according to morbidity and mortality statistics, for which a circannual pattern of variation is documented herein.     

Circannual distribution of glioblastoma and anaplastic astrocytoma diagnoses in men and women

Background: circannual variations of incidence may influence human tumors. For example, seasonal distribution of breast cancers suggests an influence of circannual hormonal rhythms. Periodicity of brain tumors has not yet been investigated. The aim of this study was to assess the seasonal variation in glioblastomas and anaplastic astrocytomas. Methods: a large dataset of high-grade gliomas (n = 697) was evaluated with the month of diagnosis as key criterion for time series and seasonal analysis. Circannual and ultra-annual cosinor models were calculated. Results: women suffering from glioblastoma show a peak incidence in fall. No suitable circannual or ultra-annual cosinor model months could be fitted to the data. In women with anaplastic astrocytoma, a peak incidence was detected in summer and fall with a nadir in spring. Here, a significant cosinor model with a period of 8.5 months could be calculated. Conclusion: our data strongly suggest seasonality of diagnosis of high-grade gliomas in women. As gliomas express hormonal receptors, an underlying endocrinal or cell proliferation rhythms may be a possible explanation.     

Photorefractoriness and Its Termination in the Subtropical House Sparrow, Passer Domesticus: Involvement of Circadian Rhythm

Groups of photorefractory female subtropical house sparrows, Passer domestkus, when treated with 6 weeks of a short photocycle (8L : 16D) showed significant ovarian growth on their return to a long photocycle (15L :9D). A 6-hr photophase coupled with scotophase of varying durations does not terminate the refractory period under photoperiod cycles of 12 (6L : 6D), 36 (6L :30D) and 60 (6L : S4D) hr but the refractory period is terminated by light-dark cycles of 24 (6L: 18D), 48 (6L :42D) and 72 (6L : 66D) hr. These results are consistent with the Biinning hypothesis of coincidence between endogenous photosensitive rhythmicity and environmental photoperiod timing that an endogenous circadian rhythm is involved in the maintenance and termination of photorefractoriness.     

A Diurnal Rhythm in Brown Adipose Tissue Causes Rapid Clearance and Combustion of Plasma Lipids at Wakening

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Circannual Rhythm of Free Fatty Acids and Diacylglycerols in 5-Day-Old Rat Cerebrum During Pentylenetetrazol-Induced Convulsions

Free fatty acids (FFA) and diacylglycerol (DG) content and composition in the cerebrum of 5-day-old rats were studied after pentylenetetrazol (PTZ)-induced convulsions. A threefold increase in brain FFA was observed 30 min after PTZ injection in experiments carried out in spring. In contrast, a 50% decrease in FFA content was observed during summer. These changes were accounted for by saturated and monoenoic fatty acids, whereas arachidonic and docosahexaenoic acids were not affected during the convulsive episode in either season. The effect of PTZ on brain DG was much smaller than it was on FFA, and less sensitive to seasonal influence. However, DG released in the summer was significantly less enriched in arachidonic acid than in the spring. Levels of FFA and DG in untreated animals were found to be subject to a circannual rhythm. Both the levels of FFA and their degree of unsaturation (unsaturated fatty acids/total FFA) were highest in summer and lowest in winter, whereas the opposite was true for DG. Circannual variations in these metabolites may be the manifestation of a programmed biological calendar regulating enzymes of brain lipid metabolism in homeotherms that under natural conditions must adapt to changing environmental temperatures.     

Isolation,Growth, Ultrastructure,and Metal Tolerance of the Green Alga,Chlamydomonas acidophila (Chlorophyta)

An acidophilic volvocine flagellate, Chlamydomonas acidophila (Volvocales) that was isolated from an acid lake, Katanuma, in Miyagi prefecture, Japan was studied for growth, ultrastructural characterization, and metal tolerance.

Chlamydomonas acidophila is obligately photoautotrophic, and did not grow in the cultures containing acetate or citrate even in the light. The optimum pH for growth was 3.5-4.5. To characterize metal tolerance, the toxic effects of Cd, Co, Cu, and Zn on this alga were also studied. Effective metal concentrations, which limited the growth by 50%, EC₅₀ were measured, after 72h of static exposure. EC₅₀s were 14.4 μM Cd²⁺, 81.3 μM Co²⁺, 141μM Cu²⁺, and 1.16 mM Zn²⁺ for 72 h of exposure. Thus, this alga had stronger tolerance to these metals than other species in the genus Chlamydomonas.     

Evidence for Chromosome Endoreduplication in Eudorina californica, a Colonial Alga

Several nuclear events seen during the cleavage period in Eudorina suggest that chromosome endoreduplication, proportional to the number of cells to be produced, may occur in the gonidia prior to cleavage. Presumably the DNA concentration is reduced to the haploid level during rapid, successive divisions of the cleavage period.
To test this hypothesis, I determined DNA content of gonidia as they grew from 4 μm to 38 μm in diameter between cleavage periods. During growth from 4 μm to 8 μm in diameter, the DNA concentration remained at the haploid level of 0.17 pg/cell. As gonidia in 64 cell colonies continued to grow from 8 μm to 33 μm in diameter, their DNA concentrations increased 60-fold.
Analysis of the Eudorina DNA by equilibrium centrifugation in CsCl showed only 2 bands with buoyant densities of 1.721 g/cm³ and 1.699 g/cm³, presumed to be nuclear and chloroplast, respectively, on the basis of labelling with ³H-thymidine and ³H-adenine. The 8: 2 ratio of the two bands did not change with increase in cell size and no other bands were detected, suggesting that both nuclear and chloroplast DNAs were synthesised proportionately prior to the cleavage period.     

Circannual Variations in Baseline Blood Values of Dogs

Forty-two hematological and biochemical variables routinely measured in dogs as part of a preoperative protocol have been analyzed for circannual changes by analysis of variance (ANOVA) and single cosinor procedures. Data were available from up to 489 adult mongrel dogs of both sexes studied on weekdays over a 5-year span (January 5, 1987 to December 18, 1991). Dogs were housed in individual cages at 24 ± 1 °C with dog chow and tap water available ad libitum and lights on between 06:00 and 18:00 h. A single blood sample/dog was collected by jugular venipuncture between 08:00 and 09:00 h and sent to a commercial laboratory for hematological and biochemical determinations. Data were assigned to date and time of sampling and analyzed for the effect of time of year by ANOVA (across 12 months and 4 seasons), and by the least-squares fit of a precise 1-year cosine. ANOVA and single cosinor described a significant circannual time effect and rhythm for the following: total leukocytes, lymphocytes, hemoglobin, mean corpuscular hemoglobin (MCH), MCH concentration, red cell distribution width, mean platelet volume, creatinine, blood urea nitrogen (BUN), BUN/crea-tinine ratio, amylase, glucose, chloride, uric acid, direct bilirubin, total protein, albumin, globulin, albumin/globulin ratio, lactate dehydrogenase, alkaline phos-phatase, γ-glutamyltransferase, alanine aminotransferase (ALT), and aspartate aminotransferase (AST)/ALT ratio. A significant effect of season by ANOVA only was found for: Ca, Na, phosphorus, total bilirubin, hematocrit, mean corpuscular volume, and neutrophils. No significant time effect could be found at p n%ge 0.05 by either statistical method for: K, Mg, Fe, cholesterol, triglycerides, ASP, red blood cells, monocytes, eosinophils, basophils, or platelets. Acrophases occurred for the most part in either the winter or summer.     

Spore classification in the genera Bangia and Porphyra

Prior to the presentation by Drew (1956) of a system of classification for spores involved in the life histories of members of the Bangiophyceae, there was no uniform scheme. With the increased attention given to field and culture studies, particularly within the Bangiaceae, it is essential that a more comprehensive terminology be developed that considers experimental data on spore production. Drew's definition of Type II spores is re-examined and a system of classification based on cell fate and cell function as defined by studies on the photobiology of the Bangiaceae is proposed.     

A Circadian Rhythm in the Activity of Superoxide Dismutase in the Photosynthetic Alga Gonyaulax polyedra

The activity of superoxide dismutase in cell-free extracts of Gonyaulax made at different times of day and night was found to be three to four times higher during the day. This rhythm continued in cells kept in constant light, indicating that the regulation can be attributed to the cellular circadian clock.     

A Circadian Rhythm in the Activity of Superoxide Dismutase in the Photosynthetic Alga Gonyaulax polyedra

The activity of superoxide dismutase in cell-free extracts of Gonyaulax made at different times of day and night was found to be three to four times higher during the day. This rhythm continued in cells kept in constant light, indicating that the regulation can be attributed to the cellular circadian clock.     

Molecular Cloning and Antiserum Development of Cyclin Box in the Brown Tide Alga Aureococcus anophagefferens

Cyclins can be useful cell cycle markers for growth rate studies on harmful algal blooms. In this study, a gene fragment corresponding to cyclin box was cloned for the brown tide alga Aureococcus anophagefferens. This algal gene fragment, designated as Btcycl1, was most similar to cyclin B. Oligopeptides based on the deduced amino acid sequence were synthesized and used to raise an antiserum that reacted on Western blots with a protein of about 63 kDa, the same size as cyclin B in other organisms. The cyclin B–like protein recognized by this antiserum, and the messenger RNA amplified using the primers, were more abundant in exponential cultures and decreased markedly in stationary cultures. This protein also appeared to be cell cycle dependent. Immunofluorescence labeling showed that this antiserum specifically stained a protein in Aureococcus cells and had no cross-reaction with bacteria that were present in the algal culture. The Btcycl1 sequence and the antiserum will provide a useful tool for studies on regulation of in situ growth rate for this brown tide alga. Received May 22, 2000; accepted July 13, 2000.