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2.
Cancer Epidemiol Biomarkers Prev ; 10(5): 509-13, 2001 May.
Article in English | MEDLINE | ID: mdl-11352862

ABSTRACT

The mu and theta classes of glutathione S-transferases (GST) may affect the development of cutaneous malignant melanoma (CMM) by decreasing cellular oxidative stress in skin. These isozymes are absent in a large proportion of the population because of germ-line homozygous deletions in the genes encoding GSTM1 and GSTT1. To determine the association between GSTM1 and GSTT1 homozygous deletions (GSTM1 null and GSTT1 null, respectively) and CMM, we studied 212 patients with CMM, 150 patients with CMM and dysplastic nevi (DN), 147 patients with DN alone, and 124 healthy persons without CMM or DN. Comparing CMM cases (n = 362) to participants without CMM (n = 271), we found no association with GSTM1 null [odds ratio (OR), 1.2; 95% confidence interval (CI), 0.86-1.6] or GSTT1 null (OR, 0.82; 95% CI, 0.56-1.2), either independently or in combination (OR, 1.4; 95% CI, 0.81-2.2), after adjusting for age. However, among the subset of participants with red or blond hair, those with CMM were twice as likely to carry GSTM1 null (OR, 2.2; 95% CI, 1.2-4.2) and nearly 10-fold more likely to carry both GSTM1 null and GSTT1 null (OR, 9.5; 95% CI, 1.2-73) compared with those without CMM. These data suggest that among persons with hair colors traditionally associated with increased risk for melanoma, absence of both GSTM1 and GSTT1 may act to further elevate CMM risk.


Subject(s)
Glutathione Transferase/genetics , Melanoma/enzymology , Skin Neoplasms/enzymology , Adult , Aged , Base Sequence , Biomarkers, Tumor/analysis , Case-Control Studies , Confidence Intervals , Female , Genotype , Glutathione Transferase/analysis , Humans , Male , Melanoma/epidemiology , Melanoma/genetics , Middle Aged , Molecular Sequence Data , Odds Ratio , Polymerase Chain Reaction , Reference Values , Sampling Studies , Sensitivity and Specificity , Skin Neoplasms/epidemiology , Skin Neoplasms/genetics , Statistics, Nonparametric
3.
Ann Ist Super Sanita ; 29(4): 581-606, 1993.
Article in English | MEDLINE | ID: mdl-7985923

ABSTRACT

A critical amount of information has accumulated over the last decades to allow the application of chronobiology to clinical and laboratory medicine. The tasks faced in laboratory medicine include the quantitative measurement of the multifrequency human time structure in health and disease. For this purpose, it is essential to choose an adequate sample size in order to obtain meaningful results and quantitative endpoints which can be interpreted by inferential statistical techniques. No statistical technique is applicable for all purposes and it is essential that the assumptions underlying each technique and its limitation are well known to the investigator. The multifrequency nature of the human time structure has to be kept in mind in order to avoid erroneous results. Time qualified reference ranges have to be established for high amplitude rhythms. Circadian and/or circannual rhythm alterations have been described as group phenomenon in subjects with epidemiologically determined risk states for common diseases, but will require much further studies for the application to individual subjects. Rhythm parameters are new endpoints in the evaluation of the human time structure in health. Alterations of these parameters may occur as cause or as consequence of disease. Recognition of rhythm abnormalities in disease are critical for a meaningful application of chronopharmacology. Time dependent changes in pharmacokinetics and pharmacodynamics have to be taken into account in the interpretation of drug level determinations. A considerable degree of individuality of timing has been documented in some frequencies. This individuality and the rhythm abnormalities found in disease require the study of reference or marker rhythms. If the complexity of the human time structure is clearly understood and its study pursued in a critical manner with quantitative endpoints, chronobiology opens a new dimension in laboratory and clinical medicine.


Subject(s)
Chemistry, Clinical , Chronobiology Phenomena , Clinical Laboratory Techniques , Adult , Blood Cell Count , Circadian Rhythm , Disease Susceptibility , Female , Hormones/metabolism , Humans , Pharmacokinetics , Reference Values , Reproducibility of Results , Secretory Rate
4.
Ann Emerg Med ; 19(5): 587-90, 1990 May.
Article in English | MEDLINE | ID: mdl-2109960

ABSTRACT

The prevalence of Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) in 232 sexual assault victims who presented for examinations between August 1, 1987, and July 31, 1988, was determined. Results are reported for cervical, rectal, and oropharyngeal NG cultures and for cervical and rectal CT smears. Results from a one-week follow-up are also reported. Cervical test results from the initial sexual assault examination were compared with cervical tests on 399 randomly selected female emergency department patients who presented for other gynecological conditions or lower abdominal pain. The victims of sexual assault had ten of 210 positive cervical NG cultures (4.76%), and 13 of 213 positive cervical CT smears (6.1%) at the first visit. These prevalence rates were not significantly different (P = .3058). There were none of 28 positive rectal NG cultures (0%) and one of 22 positive rectal CT smears (4.34%) (P = .451). None of the 43 oral NG cultures was positive. Seventy-three victims returned for follow-up examination. No follow-up cervical, rectal, or oral NG cultures were positive. However, one of 53 follow-up cervical smears for CT was positive, but this was not significantly different than for cervical NG (P = .461). Sexually assaulted patients had ten of 210 (4.76%) cervical NG cultures positive, and nonassaulted patients showed 53 of 393 positives (13.4%) (P less than .001). Assaulted patients had 13 of 213 (6.1%) cervical CT smears positive, and nonassaulted patients showed 33 of 352 (9.3%) positives (P = .11).(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Chlamydia Infections/epidemiology , Gonorrhea/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Cervix Uteri/microbiology , Child , Child, Preschool , Chlamydia Infections/etiology , Chlamydia trachomatis/isolation & purification , Emergencies , Epidemiologic Methods , Female , Gonorrhea/etiology , Humans , Minnesota , Neisseria gonorrhoeae/isolation & purification , Oropharynx/microbiology , Rectum/microbiology , Sex Offenses , Vaginal Smears
6.
Chronobiol Int ; 7(3): 203-16, 1990.
Article in English | MEDLINE | ID: mdl-2125246

ABSTRACT

Ten clinically healthy subjects (5 men and 5 women), 31 +/- 11 yrs of age, were studied at six timepoints (0800, 1200, 1600, 2000, 0000, 0400) distributed over a 1-week span. Circadian rhythms in platelet aggregation in response to adenosine diphosphate (ADP) and adrenalin (A), platelet adhesiveness measured as retention in a glass bead column, prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), fibrinogen, Factor VIII activity and alpha-1-antitrypsin antigen showed circadian rhythms. The plasma concentrations of plasminogen, alpha-2-macroglobulin, and antithrombin III (AT III) antigen, Factor V and fibrinogen degradation products showed no circadian rhythm by ANOVA or cosinor analysis. The phase relations of the rhythms of different coagulation parameters are of interest in the physiology and pathobiology of the coagulation-fibrinolytic system. The extent of the circadian rhythm (range of change) described is not of a magnitude to lead to diagnostic problems in the clinical laboratory. The timing of these rhythms, however, may determine transient risk states for thromboembolic phenomena, including myocardial infarction and stroke. Several but not all coagulation parameters suggest a transient state of hypercoagulability during the morning hours. The recognition of these rhythmic, and thus in the time of the occurrence predictable temporary risk states for thromboembolic phenomena, may lead to timed treatment and/or effective prevention.


Subject(s)
Blood Coagulation/physiology , Circadian Rhythm/physiology , Adult , Factor VIII/metabolism , Female , Humans , Hydrocortisone/blood , Male , Middle Aged , Partial Thromboplastin Time , Platelet Adhesiveness/physiology , Platelet Aggregation/physiology , Thrombin Time , alpha 1-Antitrypsin/immunology , alpha 1-Antitrypsin/metabolism
7.
Chronobiol Int ; 6(2): 131-7, 1989.
Article in English | MEDLINE | ID: mdl-2743465

ABSTRACT

Twenty-three clinically healthy, diurnally active elderly subjects, 71 +/- 5 years of age were studied over a 24-hr span (six samples). Complete blood counts and differential counts were done (Ortho ELT-8, Wright stained smears). The circadian rhythm parameters of the hematologic variables in the elderly subjects were compared with reference values obtained from a larger group of clinically healthy young adult and adult subjects studied independently. The data were analyzed by cosinor and the Bingham test. Circadian rhythms in the number of circulating formed elements in the peripheral blood persist in the aged. In comparison with the young adult, the elderly subjects show differences in the timing (phase advance) of the circadian rhythms in circulating neutrophil leukocytes and lymphocytes, a decrease in the circadian amplitude of circulating platelets, a decrease in circadian rhythm adjusted mean (mesor) in the red cell count, and in the neutrophil band forms.


Subject(s)
Aging/blood , Blood Platelets/physiology , Circadian Rhythm , Lymphocytes/physiology , Aged , Aging/physiology , Female , Hematocrit , Humans , Male
8.
Endocrinologie ; 25(2): 63-82, 1987.
Article in English | MEDLINE | ID: mdl-3629151

ABSTRACT

The circadian rhythm in serum iron concentration was studied in 61 elderly men (74 +/- 6 years of age) and 93 women (78 +/- 8 years of age) in Bucharest, Romania, in 81 clinically healthy boys and 103 girls (11 +/- 1.5 years of age) in Tîrgoviste, Romania, in 4 elderly men and 19 women (71 +/- 5 years of age) and in 75 young-adult men (24 +/- 11 years of age) and 52 women (24 +/- 9 years of age) in St. Paul, Minnesota, USA. Six samples were obtained from each subject around a 24-hour span. The sampling sessions in the elderly subjects in Romania and in the children extended over all four seasons. A circadian rhythm statistically verified by Cosinor analysis was evident in all groups in both locations. A statistically significant sex difference with lower circadian mean (mesor) and a lower amplitude in the women was found in the Romanian elderly subjects. The children in Romania showed no sex difference in any circadian rhythm parameters. The young adult subjects in Minnesota showed a significantly higher mesor and a phase delay in the men as compared with the women. The elderly subjects of both sexes at both geographic locations had a lower circadian mesor than the young adults and the children. In the Romanian elderly subjects also the circadian amplitude was lower, which was not the case in the Minnesotans. While the acrophase in the elderly subjects and in the children in Romania was comparable (0928 and 0932 local time resp.), the young adults in Minnesota showed in comparison to the Romanians a phase delay (1132 local time) and the elderly in Minnesota showed a phase advance (0732 local time) in comparison to all other groups. The latter finding will have to be confirmed by more extensive studies. In the elderly subjects in Romania the circadian rhythm in serum iron concentration was in phase with the circadian rhythms in total serum bilirubin and alkaline phosphatase but showed significant phase differences from the circadian rhythms in serum albumin, urea nitrogen (BUN), gammaglutamyl transferase (Gamma-GT), serum globulins, glucose, insulin and total serum proteins. The elderly subjects in Romania showed a statistically significant circadian phase delay in summer as compared to fall but showed no seasonal variation of the mesor. The children showed a circadian phase advance in fall as compared to the other seasons and a seasonal variation of their mesor with higher values in spring and summer as compared with winter and fall.(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Aging/metabolism , Circadian Rhythm , Iron/blood , Adolescent , Age Factors , Aged , Aged, 80 and over , Aging/blood , Child , Female , Humans , Iron/metabolism , Male , Minnesota , Romania , Seasons , Sex Factors
9.
Prog Clin Biol Res ; 227A: 281-96, 1987.
Article in English | MEDLINE | ID: mdl-3601965

ABSTRACT

The circadian rhythms in the numbers of circulating formed elements in the peripheral blood were studied in 712 CD2F1, 188 BDF1, and 250 Swiss Webster mice kept under a lighting regimen of LD 12:12 (L 0600 to 1800 hr), a room temperature of 21 +/- 1 degree C, and food and water available ad libitum. The circadian rhythms were evaluated by the single cosinor procedure. The rhythm parameters--mesor, amplitude, and acrophase--the percentage of total variability attributable to the circadian rhythm, and the extent of the circadian rhythm are presented as guidelines for experimental design and evaluation. Under the conditions of this study, the mice of all three strains and both sexes show circadian variations, which are similar in their timing, in their red and white cell parameters. The percent of the total variance attributable to the circadian rhythms of each function varies between the strains studied in our laboratory being lowest in the Swiss Webster female mice. The extent of the circadian variation as expressed by the double amplitude as percent of mesor is similar in the three strains and between males and females. In relation to rest and activity spans, the hematologic circadian time structure in the nocturnally active mouse is different from that in diurnally active human subjects. The red-cell parameters show an acrophase in the middle of the rest span instead of the middle of the activity span as in human subjects. The lymphocytes and eosinophils in the mouse show an acrophase during the rest span that is similar to human subjects. In contrast to human subjects, however, neutrophils and monocytes show their acrophase in the first half of the rest span rather than during the second half of the daily activity span. The circulating formed elements in the peripheral blood thus follow a different circadian timing in the mouse than in human subjects; this has to be kept in mind when the time structure of the two species is compared, e.g., in models for experimental chemotherapy.


Subject(s)
Blood Cell Count , Circadian Rhythm , Hematocrit , Hemoglobins/analysis , Animals , Erythrocyte Count , Female , Hybridization, Genetic , Leukocyte Count , Male , Mice , Mice, Inbred Strains , Sex Factors , Species Specificity
10.
Endocrinologie ; 23(1): 39-53, 1985.
Article in English | MEDLINE | ID: mdl-3992157

ABSTRACT

Sixty-two elderly men (average age 75 +/- 6 yrs) and 85 elderly women (average age 79 +/- 8 yrs) institutionalized at Berceni Clinical Hospital, Bucharest, Romania, were investigated over a 24 hour span, some of them repeatedly, leading to a total of 269 profiles. The subjects were studied in 12 subgroups spread over all four seasons. Total serum calcium, inorganic phosphate, total protein, albumin and urinary calcium and magnesium were determined. Circadian rhythms were found in all variables. There were statistically significant phase differences between serum calcium, total protein and serum albumin speaking against the serum protein rhythm (or circadian variations in hydration) being responsible for the circadian rhythm in total serum calcium. There are phase differences between the elderly (and young) subjects studied in Romania and several series reported from Germany and the USA. Circadian and circannual variations were found for urinary calcium and magnesium excretion, with maximum in fall and low values during summer. The peak excretion thus follows, rather than coincides, with the time of maximum sun exposure. The elderly subjects studied in Romania show a relatively low circadian (24-hour) mean calcium excretion, and the circadian acrophase in the elderly occurs during the night hours in keeping with the acrophase shift found in elderly subjects in urine volume and other electrolytes.


Subject(s)
Calcium/metabolism , Circadian Rhythm , Magnesium/urine , Seasons , Aged , Aging , Blood Proteins/metabolism , Female , Humans , Male , Middle Aged , Phosphates/blood , Serum Albumin/metabolism , Serum Globulins/metabolism , Sex Factors , Urine
11.
Endocrinologie ; 22(4): 227-43, 1984.
Article in English | MEDLINE | ID: mdl-6523019

ABSTRACT

Forty-one endocrine and biochemical serum parameters were studied over a 24-hour span with 6 samples at 4-hour intervals in 20 non-insulin dependent (Type II) diabetics and in 20 non-diabetic subjects matched for sex, age, height and weight. Circadian rhythms were verified by cosinor analysis. Group-synchronized circadian rhythms were detected in diabetic and non-diabetic subjects with no statistically significant difference in any of the rhythm parameters (rhythm adjusted mean, amplitude and acrophase) in: Aldosterone, cortisol, insulin, 17-OH progesterone, prolactin, testosterone, TSH, and in serum albumin, creatine phosphokinase (CPK), serum iron, inorganic phosphate and total protein. Statistically significant (p less than .05) circadian rhythms in both groups with a difference in some parameters between the diabetic and the non-diabetic subjects, which were verified by the Bingham Test (p less than .05) were found with a difference in the mesor in cholesterol, glucose, urea nitrogen (BUN), in the amplitude in C-peptide and in the acrophase in triglycerides, globulin and reverse T3 (rT3). Statistically significant circadian rhythms were detected as a group phenomenon for the diabetics only in progesterone, free and total T4, chloride, calcium, bilirubin and LDH and in the non-diabetic subjects only in ACTH, LH, total T3, alkaline phosphatase, uric acid and potassium. In the remainder of the functions studied, a circadian rhythm was detectable with statistical significance by cosinor analysis as a group phenomenon neither in the diabetics nor in the matched non-diabetic controls (DHEA-S, estradiol, FSH, GH, glucagon, free T3, sodium, GOT and gamma GT). In the absence of a detectable circadian rhythm as group phenomenon, the circadian mean was different between the diabetics and the non-diabetic subjects in sodium, chloride and calcium which were higher in the diabetic patients and serum LDH which was lower. In a comparison of endocrine determinations in the two groups, the circadian mean or mesor in T3 was lower in the diabetics and ACTH higher, without corresponding changes in TSH or in corticosteroids. The circadian time structure of Type II diabetic patients thus seems to be very similar to that seen in non-diabetic subjects of the same sex, age, weight and height. The minor differences found in some rhythm parameters will have to be confirmed or excluded in larger numbers of subjects. The higher circadian mean ACTH concentrations without change in steroid rhythm parameters observed in this group is interesting but will also require confirmation.(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Circadian Rhythm , Diabetes Mellitus, Type 2/blood , Endocrine Glands/physiopathology , Aged , Blood Chemical Analysis , Body Height , Body Weight , Female , Hormones/blood , Humans , Male
12.
Am J Anat ; 168(4): 467-517, 1983 Dec.
Article in English | MEDLINE | ID: mdl-6364772

ABSTRACT

The hematopoietic and the immune systems in all their components are characterized by a multifrequency time structure with prominent rhythms in cell proliferation and cell function in the circadian, infradian, and rhythms in cell proliferation and cell function in the circadian, infradian, and circannual frequency ranges. The circulating formed elements in the peripheral blood show highly reproducible circadian rhythms. The timing and the extent of these rhythms were established in a clinically healthy human population and are shown as chronograms, cosinor summaries and, for some high-amplitude rhythms, as time-qualified reference ranges (chronodesms). Not only the number but also the reactivity of circulating blood cells varies predictably as a function of time as shown for the circadian rhythm in responsiveness of human and murine lymphocytes in vitro to lectin mitogens (phytohemagglutinin and pokeweed mitogen). Some circadian rhythms of hematologic functions appear to be innate and are presumably genetically determined but are modulated and adjusted in their timing by environmental factors, so-called synchronizers. Phase alterations in the circadian rhythms of hematologic parameters of human subjects and of mice by manipulation of the activity-rest or light-dark schedule and/or of the time of food uptake are presented. Characteristically these functions do not change their timing immediately after a shift in synchronizer phase but adapt over several and in some instances over many transient cycles. The circadian rhythm of cell proliferation in the mammalian bone marrow and lymphoid system as shown in mice in vivo and in vitro may lend itself to timed treatment with cell-cycle-specific and nonspecific agents in an attempt to maximize the desired and to minimize the undesired treatment effects upon the marrow. Differences in response, and susceptibility of cells and tissues at different stages of their circadian and circaseptan (about 7-day) rhythms and presumably of cyclic variations in other frequencies are expected to lead to the development of a chronopharmacology of the hematopoietic and immune system. Infradian rhythms of several frequencies have been described for numerous hematologic and immune functions. Some of these, i.e., in the circaseptan frequency range, seem to be of importance for humoral and for cell mediated immune functions including allograft rejection. Infradian rhythms with periods of 19 to 22 days seem to occur in some hematologic functions and are very prominent in cyclic neutropenia and (with shorter periods) in its animal model, the grey collie syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)


Subject(s)
Allergy and Immunology , Biological Clocks , Hematology , Adolescent , Adult , Animals , Blood Cells/physiology , Blood Physiological Phenomena , Bone Marrow Cells , Capillaries , Cell Division , Child , Circadian Rhythm , Disease Susceptibility , Dog Diseases/pathology , Dogs , Female , Forecasting , Hematopoiesis , Humans , Immunity , Immunity, Innate , Leukemia, Myeloid/pathology , Lymphocytes/classification , Lymphocytes/immunology , Lymphocytes/physiology , Lymphoid Tissue/cytology , Lymphoid Tissue/immunology , Male , Menstruation , Mice , Mice, Inbred Strains , Middle Aged , Mitogens/immunology , Neutropenia/pathology , Periodicity , Pharmaceutical Preparations/administration & dosage , Rats , Seasons
13.
Endocrinologie ; 21(1): 3-21, 1983.
Article in English | MEDLINE | ID: mdl-6342116

ABSTRACT

The circadian rhythms of twenty-one chemical serum parameters (albumin, alkaline phosphatase, calcium, carbon dioxide content, chloride, cholesterol, creatine phosphokinase (CPK), creatinine, glucose, glutamic-oxalacetic transaminase (GOT), gamma glutamyl transferase (Gamma--GT), lactate dehydrogenase (LDH), inorganic phosphorus, iron, potassium, total bilirubin, total protein, sodium, triglycerides, urea nitrogen, uric acid) and of urinary volume and oral temperature were studied, in October 1981, in a group of 49 elderly subjects (23 men, 73 +/- 6 years of age, and 26 women, 77 +/- 8 years of age) institutionalized at the Berceni Hospital for the aged. Statistically significant circadian rhythms as a group phenomenon were found in all functions except alkaline phosphatase, GOT, and LDH. The timing and the extent of these rhythms are presented. The circadian time structure of body chemistry appears well maintained in old age. Some circadian rhythms show a large enough amplitude to require the establishment of time qualified reference ("normal") ranges (e.g. serum iron). In most others, the circadian amplitudes are small and at present of little or no diagnostic importance. They are, however, of physiologic and pathophysiologic interest indicating an intricate time sequence of metabolic events in the human body.


Subject(s)
Blood Glucose/metabolism , Blood Proteins/metabolism , Circadian Rhythm , Electrolytes/blood , Enzymes/blood , Lipids/blood , Age Factors , Aged , Blood Chemical Analysis , Blood Urea Nitrogen , Chronology as Topic , Female , Humans , Male
14.
Am J Clin Pathol ; 78(1): 69-77, 1982 Jul.
Article in English | MEDLINE | ID: mdl-7102609

ABSTRACT

Urinary N-acetyl-beta-glucosaminidase (NAG), a lysosomal enzyme of renal tubular origin, has been shown to be a sensitive indicator of renal tubular function. This study documents a circadian rhythm in the urinary activity of NAG, statistically validated and quantified by the cosinor method, in 19 female and 15 male human subjects. The acrophase of the circadian rhythm in urinary NAG activity occurs at 09(40) with 95% confidence limits between 08(40) and 12(08) and is similar to the timing of the circadian rhythm in urinary free cortisol. The circadian acrophase of urinary NAG activity lags in timing the circadian rhythms in urine volume, Na and K excretion, and urinary free adrenalin and noradrenalin, by about five to ten hours and the circadian rhythm in creatinine excretion by about 11 hours. These functions with their characteristic phase relations are part of the internal circadian time structure of the human organism, and may provide internal phase references, independent of the "time of day." This study also documents a sex difference in mesor of the circadian rhythms in urinary NAG activity, with female subjects having a higher mesor and amplitude than the male subjects, and in the excretion of creatinine and potassium, with male subjects having a higher mesor and amplitude than the female subjects.


Subject(s)
Acetylglucosaminidase/urine , Circadian Rhythm , Hexosaminidases/urine , Adolescent , Adult , Creatinine/urine , Female , Humans , Hydrocortisone/urine , Male , Potassium/urine , Sex Factors , Sodium/urine , Time Factors
15.
Prog Clin Biol Res ; 59C(00): 165-83, 1981.
Article in English | MEDLINE | ID: mdl-7279961

ABSTRACT

The Harding-Passey melanoma in Bal/C or CD2F1 female mice shows, in light synchronized (LD12:12) undisturbed animals, no detectable circadian rhythm in cell proliferation as gauged by 3H-thymidine uptake in DNA. Manipulation of the animals and saline injection (.2 ml/20 gm), hydroxyurea injection (10 mg/ .2 ml/20 gm), and ACTH-17 (HOE 433) (.4 IU/ .2 ml/20 gm) induced a statistically significant circadian variation detected in several studies 4-24 and 16-36 hours after the treatment, only if the injection is given at the beginning of the light phase (LD12:12). Thus, tumor synchronization in this model is critically dependent upon the circadian stage of administration of the synchronizing agent. Endogenous and exogenous ACTH seem to be the synchronizing agent. Hydroxyurea in the dose given shows no additional effect.


Subject(s)
Circadian Rhythm , Melanoma/physiopathology , Animals , Bone Marrow/metabolism , Circadian Rhythm/drug effects , DNA Replication/drug effects , Darkness , Female , Hydroxyurea/pharmacology , Light , Mice , Mice, Inbred BALB C , Neoplasms, Experimental/physiopathology
16.
Ann Neurol ; 8(5): 539-41, 1980 Nov.
Article in English | MEDLINE | ID: mdl-7436396

ABSTRACT

Seasonal periodicity in the onset of spontaneous intracerebral hemorrhage was studied in 118 consecutive cases occurring during a six-year span. The patients were urban residents of eastern Minnesota, a region characterized by wide seasonal fluctuations in daylight and temperature. The greatest number of cases consistently occurred each year during January and February. Circannual (about one year) periodicity was demonstrated by statistical analysis using rhythmometric techniques. This periodicity coincided with that reported for mortality from cerebrovascular and cardiovascular diseases in the United States and elsewhere. Available information suggests that in populations at high risk for vascular diseases, climatic conditions might act as synchronizers to endogenous rhythms influencing the periodic occurrence of pathological vascular events.


Subject(s)
Cerebral Hemorrhage/epidemiology , Seasons , Adult , Aged , Female , Humans , Male , Middle Aged , Minnesota
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