Genetic "clocks" and "soft" events: a twin model for pubertal development and other recalled sequences of developmental milestones, transitions, or ages at onset

Two groups of mouflons (Ovis ammon) were held in captivity to study the effects of repeated capture on physiological, haematological and biochemical parameters. The first one (Group I) was of 6 mouflons captured in the wild, while the second (Group II) was also of 6 mouflons, but which had been in captivity for 3 years. In Group I, body temperature, mature neutrophil count and lactate increased during activity, while red blood cells, haemoglobin, ALT, AST, total lipid, phospholipids, cholesterol, BUN, creatinine, phosphorus and zinc decreased at different times during the study period. In Group II, few statistical differences were observed. Most of these changes were related to stress and reflected a lack of adaptation to repeated handling.     

Prevalence of hypercalcaemia in a health screening in Stockholm

A free health check, offered to 21417 20-63-year-old employees of the Stockholm City and County Council in 1971-73, was accepted by 15903 persons. The examination included a multichannel chemical analysis of a single blood sample. Serum calcium levels greater than or equal to 11.0 mg/100 ml (2.75 mmol/l) and greater than or equal to 11.1 mg/100 ml (2.78 mmol/l) were encountered in 3.9% and 1.1% of the population, respectively. Among subjects below 50 years of age, the calcium concentration was significantly higher in males than in females. This difference disappeared in older subjects, essentially because the calcium level decreased with advancing age in the men. To a further investigation were invited 178 subjects with a single serum calcium registration greater than or equal to 11.1 mg/100 ml (2.78 mmol/l). Of this group, 95 persons (53.4%) exhibited hypercalcaemia (HC) on repeated testing. Twelve had been operated on prior to the actural follow-up and found to have parathyroid adenomata. Twenty subjects were on continuous treatment with diuretics of the thiazide type and seven had diseases that might induce HC (two had hyperthyroidism, two hypothyroidism, one sarcoidosis, one hypernephroma and one mammary carcinoma). In 56 patients the laboratory and physical examinations did not reveal any obvious cause for the HC except possible hyperparathyoidism (HPT). Eighty (84.2%) of the 95 HC subjects were women, mostly over 50 years. The 95 persons constituted 6% of the total number of health-screened persons. The highest prevalence, 13%, was recorded for women aged 60-63. The prevalence of HPT in the total material was 3.6%, which is higher than that found in several other studies. This is based on surgical findings to date.     

Towards an understanding of nuclear morphogenesis

Hematological parameters were measured in 408 blood samples collected over a 30-mo period from 254 captive mountain gazelles (Gazella gazella) in Saudi Arabia. We evaluated the influence of sex, age, capture method, and season, on these parameters. Evaluations also were made with a small number of anesthetized animals. Males had a significantly higher mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) than females. There was no observed neutrophil: lymphocyte ratio shift for either sex during the first months of life. The effects of different capture methods generally were similar in males and females and included a significantly lower MCV and MCH after quick capture. Animals undergoing slow capture had a significantly lower mean corpuscular hemoglobin concentration (MCHC), and very pronounced stress neutrophilia. We propose that this stress neutrophilia caused the permanently high neutrophil: lymphocyte ratio (62:36 average for all gazelles tested) and the lack of a neutrophil: lymphocyte shift in young animals. Erythrocyte counts were significantly higher in summer, while packed cell volume and hemoglobin concentration were the same in summer and winter; thus there was a significantly lower MCV and MCH, and a significantly higher MCHC in summer in both sexes. Fibrinogen varied significantly by sex, age, capture method, and anesthesia.     

Associations between acute lipid stress responses and fasting lipid levels 3 years later.

The authors assessed the association between lipid responses to acute mental stress and fasting serum lipid levels 3 years later in 199 middle-aged men and women. Total cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol increased following moderately stressful behavioral tasks. LDL cholesterol, HDL cholesterol, and total:HDL ratio measured 3 years later were predicted by acute stress responses independent of gender, age, socioeconomic position, change in body mass, smoking, alcohol consumption, or hormone replacement therapy baseline lipid levels. The odds of clinically elevated cholesterol were significantly greater in the highest compared with the lowest stress tertile, independent of baseline levels and covariates. Acute lipid stress responsivity may reflect processes that contribute to the development of elevated blood cholesterol concentration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sepsis and serum cytokine concentrations

Hematological and plasma chemistry parameters were measured in 129 juvenile white storks (Ciconia ciconia), either wild or captive bred, April to June 1994. Wild storks were members of a colony in the Lozoya River Valley, Madrid, Spain. Red blood cells count, packed cell volume and hemoglobin increased significantly with age. White blood cells count, lymphocytes count and platelets decreased with age. Total solids, total proteins, fibrinogen, albumin, alpha, beta, gamma-globulins and urea increased with age. Differences between captive and wild birds were not notable.     

Cognitive functions of school children with normal IQ and histories of severe and early malnutrition

Reference values of some hematologic and plasma chemical parameters were established in two species of clinically normal Cercopithecidae. The following variables were studied in seven mandrills (Mandrillus sphinx) and nine white-crowned mangabeys (Cercocebus torquatus lunulatus): hematocrit, hemoglobin concentration, erythrocyte and leucocyte counts, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, glucose, urea, uric acid, cholesterol, creatinine, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, creatinine phosphokinase, lactic dehydrogenase, gamma glutamyl transpeptidase, total serum proteins, albumin, globulins, albumin-globulin ratio, sodium, potassium, calcium, magnesium, total phosphorus, chloride, and serum osmolality. Few differences were observed when compared with human hematological data and with other species of Cercopithecidae Primates.     

Hematological and blood chemical values of mallard, Anas p. platyrhynchos, drakes before, during and after remige moult

Hematological and blood chemical values were determined for wild and captive mallards, Anas p. platyrhynchos, for the late spring period prior to remige moult through early fall migration. Hemoglobin, packed cell volume, erythrocyte and total leukocyte counts, as well as the number of heterophils and lymphocytes, declined significantly during and after remige moult compared to values recorded prior to remige moult. During fall migration mallard drakes had elevated levels of glucose and uric acid. No significant changes were observed in total protein, alkaline phosphatase, glutamic oxaloacetic transaminase or creatine phosphokinase in pre- or post-moult periods. The hematological and biochemical values should prove useful in providing background information on mallard drakes, and documenting baseline data for intra and interspecies comparisons with diseased birds.     

Population-based screening for primary hyperparathyroidism with serum calcium and parathyroid hormone values in menopausal women

BACKGROUND: Population-based screenings for primary hyperparathyroidism have failed to systematically use intact parathyroid hormone (PTH) values for diagnosis, to explore prevalence and diagnostic criteria of normocalcemic hyperparathyroidism, and to attempt surgical verification of the disorder. METHODS: A total of 5202 women (ages, 55 to 75 years) attending a population-based mammography screening were investigated for primary hyperparathyroidism. In women lacking a family history of hypercalcemia, significant renal impairment, or low urinary calcium excretion hyperparathyroidism was diagnosed on the basis of predetermined criteria encompassing lower intact serum PTH levels in hypercalcemia (serum PTH 25 ng/L or greater; reference range, 12 to 55 ng/L) than in two intervals of normocalcemia (serum PTH 35 or greater, greater than 55 ng/L). RESULTS: Prevalence of hyperparathyroidism was 2.1% (n = 109). At diagnosis total serum calcium and serum PTH levels were 2.32 to 3.19 mmol/L and 34 to 300 ng/L, respectively, and 66% of the women exhibited normocalcemia. Repeated examination showed persistent normocalcemia in 30 patients, and all but two of them had normal ionized plasma calcium levels. Significantly higher serum calcium, serum PTH, and urine calcium--but not serum creatinine--levels were found in patients with hyperparathyroidism compared with matched control subjects from the screened population. Within an ongoing stratified treatment program, 59 of 60 patients who underwent operation exhibited pathologic parathyroid tissue (mean weight, 591 mg). CONCLUSIONS: Substantial prevalence of sporadic primary hyperparathyroidism is demonstrated in a risk group. Although criteria for hyperparathyroidism recognition included patients with truly mild biochemical derangement, operative findings suggested underdiagnosis of the disorder.     

Results of an oral rabies vaccination program for coyotes

OBJECTIVE: To determine effectiveness of large-scale distribution of an oral rabies vaccine contained in a palatable bait for halting expansion of a canine rabies epizootic in coyotes (Canis latrans). DESIGN: Prospective study. ANIMALS: 98 coyotes during prevaccination surveillance and 449 coyotes and 60 other wild animals during postvaccination surveillance. PROCEDURE: A vaccinia recombinant oral rabies vaccine was inserted into an edible bait for coyotes that also contained tetracycline as a biomarker. Vaccine units were then distributed via aircraft, using automated distribution equipment and flight plans developed by incorporating global positioning system equipment. The target area was along the northern edge of an area that had an epizootic of canine rabies. This area was identified through previously conducted epidemiologic surveillance of rabies cases. During postvaccination surveillance, dental specimens were examined for biomarker evidence of bait acceptance, and serum samples were analyzed for rabies neutralizing antibodies. RESULTS: Samples from 449 coyotes were obtained during postvaccination surveillance. Seroconversion was detected in 39 of 96 (40.6%) coyotes that had evidence of tetracycline biomarker. Additionally, the number of rabies cases in the target area decreased, and expansion of the epizootic area ceased. CLINICAL IMPLICATIONS: Mass distribution of an oral rabies vaccine in a palatable bait is an effective means to halt expansion of a rabies epizootic involving coyotes.     

Free-operant comparisons of wild and domestic Norway rats.

Compared 16 wild and 16 domestic hooded rats on nondifferential appetitive VI responding, discrimination, and discrimination reversal procedures. The effects of strain, sex, deprivation, preexperimental handling, and sessions on response rate were examined. Performances during the 60 days of VI training showed prolonged increases over that period for all strain-sex groupings, with domestic Ss responding at higher rates than wild. Males also tended to respond at higher rates than females. During the discrimination procedure wild Ss showed more resistance to extinction, although these differences generally diminished after the 30 days of training. During the discrimination reversal procedure domestic Ss reversed their responding pattern more readily, and domestic females reached criterion significantly sooner than domestic males. The effects of deprivation and handling were not significant during the experimental procedures.(20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social support among African-American adults with diabetes, Part 2: A review

STUDY OBJECTIVE: To study differences in cardiovascular lifestyle risk factors and biological risk markers in early adult life, with special attention to age and sex differences. Lifestyle cardiovascular risk factors included dietary habits, physical inactivity, smoking, alcohol habits, psychosocial strain, and mental stress. Biological risk markers included anthropometric variables, arterial blood pressure, and serum cholesterol concentration. DESIGN: A combined individual and community based preventive programme, including health examinations. SETTING: All communities in the County of Skaraborg in south western Sweden. PARTICIPANTS: Altogether 12,982 men and women aged 30 or 35 years who underwent health examinations over seven years. MAIN RESULTS: In both sexes, biological risk markers studied were worse in 35 year old subjects than in 30 year olds. Furthermore, a larger proportion of men aged 35 years were smokers and were physically inactive compared with 30 year old men. However, dietary habits were better in both sexes in the upper age group. At both ages there were also significant differences between men and women. Women, compared with men, had better dietary habits and lower alcohol consumption but smoked more and experienced greater mental stress and psychosocial strain. All biological risk markers were worse in men than in women at both ages studied. During the observation period, some improvement of the health profile of the participants was observed, indicating a beneficial effect of the intervention programme. CONCLUSIONS: The results indicate that the risk of cardiovascular disease, as assessed from studying lifestyle and biological risk markers, increases early in life, suggesting that preventive measures should start early.     

Linkage of chromosome 5q and 11q gene markers to asthma-associated quantitative traits in Australian children

Asthma is a genetically complex disease, and the investigation of putative linkages to candidate loci in independent populations is an important part of the gene discovery process. This study investigated the linkage of microsatellite markers in the 5q and 11q regions to asthma-associated quantitative traits in 121 Australian Caucasian nuclear families. The families were recruited on the basis of a child proband: a cohort of 95 randomly recruited families of unselected probands (n = 442 subjects) and a cohort of 26 families of probands selected on the basis of severe symptomatic asthma (n = 134 subjects). The quantitative traits assessed included serum levels of total IgE and specific IgE to house dust mite and mixed grass, blood eosinophil counts, and the dose-response slope (DRS) of FEV1 to histamine provocation. Multipoint linkage analysis using Haseman-Elston sib-pair methods provided evidence of significant linkage between the chromosome 5q markers and loge total serum IgE levels, specific serum IgE levels, and loge blood eosinophil counts. The chromosome 11q markers showed evidence of significant linkage to specific serum IgE levels. Neither region demonstrated significant linkage to the loge DRS to histamine. Phenotypes were residualized for age and sex. These data are consistent with the existence of loci regulating asthma-associated quantitative traits in both the 5q31-33 and 11q13 chromosomal regions.     

Free and total insulin-like growth factor I (IGF-I), IGF-binding protein-1 (IGFBP-1), and IGFBP-3 and their relationships to the presence of diabetic retinopathy and glomerular hyperfiltration in insulin-dependent diabetes mellitus

The existing literature on serum insulin-like growth factor I (IGF-I) levels in insulin-dependent diabetes mellitus (IDDM) is conflicting. Free IGF-I may have greater physiological and clinical relevance than total IGF-I. Recently, a validated method has been developed to measure free IGF-I levels in the circulation. Serum free and total IGF-I, IGF-binding protein-1 (IGFBP-1), and IGFBP-3 levels were measured in 56 insulin-treated IDDM patients and 52 healthy sex- and age-matched controls. Diabetic retinopathy was established by direct fundoscopy. In 54 IDDM patients, the glomerular filtration rate (GFR) and effective renal plasma flow were calculated from the clearance rate of [125I]iothalamate and [131I]iodohippurate sodium. Fasting free IGF-I, total IGF-I, and IGFBP-3 levels were significantly lower in IDDM patients than in age- and sex-matched healthy controls (free IGF-I, P < 0.005; total IGF-I, P < 0.001; IGFBP-3, P = 0.001), whereas IGFBP-1 levels were higher (P < 0.001). In IDDM subjects, decreases in free IGF-I, total IGF-I, and IGFBP-3 levels with age were observed (free IGF-I, r = -0.27 and P = 0.05; total IGF-I, r = -0.52 and P < 0.001; IGFBP-3, r = -0.37 and P = 0.005). Free IGF-I was inversely related to fasting glucose in IDDM subjects (r = -0.35; P = 0.01), whereas the relationship between total IGF-I and fasting glucose did not reach significance (r = -0.27; P = 0.06). Age-adjusted free IGF-I levels were significantly higher (P < 0.05) in IDDM subjects with retinopathy than in subjects without retinopathy after adjustment for age. Total IGF-I and IGFBP-3 levels were positively related to GFR (total IGF-I, r = 0.35 and P < 0.05; IGFBP-3, r = 0.28 and P < 0.05). Both of these differences lost significance after adjustment for age. Free IGF-I, total IGF-I, and IGFBP-3 levels were lower and IGFBP-1 levels were higher in insulin-treated IDDM subjects compared to those in age- and sex-matched controls. Free IGF-I, total IGF-I, and IGFBP-3 levels decreased significantly with age in IDDM subjects. Age-adjusted free IGF-I levels in subjects with diabetic retinopathy were higher than those in subjects without diabetic retinopathy. Total IGF-I and IGFBP-3 levels were positively related to GFR in IDDM subjects, but these relations were lost after adjustment for age. Measurement of serum free IGF-I levels in IDDM subjects did not have clear advantages compared to that of total IGF-I, IGFBP-1, and IGFBP-3 levels. Serum IGF-I and IGFBPs reflect their tissue concentrations to a various degree. Consequently, extrapolations concerning the pathogenetic role of the IGF/IGFBP system in the development of diabetic complications at the tissue level remain speculative.     

Appendicular bone mass in children with a high prevalence of low dietary calcium intakes

We have previously documented evidence of dietary calcium deficiency in black children living in a rural community in the eastern part of South Africa. The present study determined the bone mass of the distal one-third of the radius in a random sample of children living in the same community and compared their bone mass measurements with those of black children living in a similar rural community but without evidence of dietary calcium deficiency. Further, factors (weight, height, serum corrected total calcium, phosphorus, and alkaline phosphatase [ALP]) that might influence appendicular bone mass were assessed and correlated with the bone mass measurements. A random sample of 306 boys and 345 girls between the ages of 1 and 20 years were included in the study. Hypocalcemia was found in 6.5% of the boys and 5% of the girls, while elevated ALP values were recorded in 20 and 26% of the boys and girls, respectively. After adjusting for differences in age, weight, and height, bone mineral density (BMD) and bone mineral apparent density (BMAD) were significantly lower and bone width (BW) greater in study than control children. In a stepwise regression analysis, weight and/or height accounted for the majority of the observed variance in BMC, BW, and BMD; however, a significant effect of serum calcium (positively) and ALP (negatively) on BMC and BMD was also found. In boys, but not girls, serum ALP also had a positive effect on BW.BMAD was negatively correlated to ALP and positively correlated to serum calcium in both boys and girls. Those children with hypocalcemia or elevated ALP levels had significantly lower BMC, BMD, and BMAD and a trend toward greater BW than children with normal biochemistry. The findings suggest that low dietary calcium intake may have a detrimental effect on appendicular bone density in rural black children. Whether or not these effects are disadvantageous in the long-term is not known.     

Intracellular calcium and blood pressure: comparison between primary hyperparathyroidism and essential hypertension

Intracellular calcium has been reported to be increased in essential hypertension, and thought to play a role in its genesis through facilitation of vascular smooth muscle contraction. Since hypertension is more prevalent in primary hyperparathyroidism, intracellular calcium may also be increased in this condition. To investigate whether the hyperparathyroid condition, i.e., hypercalcemia and increased PTH per se, could be associated with high intracellular calcium, we measured intracellular calcium in platelets with the Quin-2 AM fluorometric method in 11 normotensive patients with primary hyperparathyroidism, 15 patients with essential hypertension, and 18 normal controls, all matched for age and sex. We repeated the measurements in 9 of the hyperparathyroid patients after successful surgery. We found that intracellular calcium was higher in normotensive patients with primary hyperparathyroidism than in normal controls (198 +/- 24 vs 113 +/- 11 nM, p < 0.05), but lower than in patients with essential hypertension (198 +/- 24 vs 286 +/- 38 nM, p < 0.05). Successful removal of a parathyroid adenoma decreased intracellular calcium from 215 +/- 22 to 116 +/- 19 nM, (p < 0.01). In the patients with primary hyperparathyroidism, intracellular calcium was strongly correlated with the levels of PTH (r = 0.87, p < 0.01), but not with the total serum calcium levels (r = 0.04, NS). The decrease in intracellular calcium after parathyroidectomy was also strongly correlated with the decrease in PTH (r = 0.84, P < 0.01), but not with the decrease in total serum calcium (r = 0.16, NS). In the patients with essential hypertension, intracellular calcium correlated well with systolic (r = 0.69, p < 0.01), diastolic (r = 0.76, p < 0.01) and especially mean arterial pressure (r = 0.86, P < 0.01). There was no correlation between blood pressure and intracellular calcium in the patients with primary hyperparathyroidism. We conclude that normotensive patients with primary hyperparathyroidism, as well as patients with essential hypertension, can have increased concentrations of intracellular calcium in platelets. The correction of the hyperparathyroid condition normalizes intracellular calcium concentration. The close correlation between PTH and intracellular calcium suggests that PTH may act as a ionophore for calcium entry into cells. Whether the increased levels of intracellular calcium may reflect a pre-hypertensive condition in normotensive patients with primary hyperparathyroidism remains to be determined.     

Chronic social stress produces reductions in available splenic type II corticosteroid receptor binding and plasma corticosteroid binding globulin levels

Adult male and female rats were housed for 2 weeks in a Visible Burrow System resulting in the development of strong dominant-subordinate relationships among the male rats. Neuroendocrine measures indicated that the subordinate rats, and to a lesser extent dominant rats, experienced chronic HPA axis hyperstimulation during the 2 week experience. This paper focuses on the consequences of this chronic social stress on cytosolic type II corticosteroid receptor binding in the spleen. In the first study, rats were adrenalectomized 18 h prior to sacrifice in order to measure total cellular receptor protein levels in each animal. In spite of the severity of the social stress, there was no decrease in splenic type II corticosteroid receptor binding levels in these short-term adrenalectomized animals. In the second study, rats were left adrenal-intact. Corticosteroid receptor levels in these adrenal-intact animals reflect the level of receptors (available receptors) that were unoccupied by endogenous hormone at the time of sacrifice. Both subordinate and dominant rats had fewer available splenic type II receptors than control rats, suggesting that a greater proportion of receptors in subordinate and dominant rats were occupied and activated by endogenous hormone at the time of sacrifice than in control rats. The differences in available receptor levels were not a function of total plasma corticosterone levels at the time of sacrifice (mean corticosterone levels were the same for control and subordinate rats). Instead, the differences in available receptor levels may have been a function of plasma corticosteroid binding globulin (CBG) levels which regulate free corticosterone levels. There was a large reduction in plasma CBG levels of subordinate (-70%) and dominant (-40%) rats relative to control rats, and there was a significant correlation between plasma CBG level and available type II receptors in the spleen. These results suggest that a decrease in CBG levels as a result of chronic social stress led to greater access of free corticosterone hormone to type II receptors in the spleen than is typically present in rats under basal or acute stress conditions. This result illustrates one mechanism by which chronic stress may have a greater impact than acute stress on splenic immune function.     

Sex differences in endocrine and psychological responses to psychosocial stress in healthy elderly subjects and the impact of a 2-week dehydroepiandrosterone treatment

Evidence from animal as well as human studies has suggested that significant sex differences exist in hypothalamus-pituitary-adrenal axis (HPA) activity. As gonadal steroids could be important modulators of HPA sex differences, stress responses were investigated in subjects of advanced age after dehydroepiandrosterone (DHEA) or placebo treatment. After a 2-week treatment with 50 mg DHEA daily or placebo, 75 men and women (mean age, 67.6 yr) were exposed to the Trier Social Stress Test (TSST). The TSST is a brief psychosocial stress that consists of a free speech and mental arithmetic task in front of an audience. The results show that the TSST induced significant increases in ACTH, salivary free cortisol, total plasma cortisol, norepinephrine, and heart rates (all P < 0.0001) as well as decreased positive affect in the elderly (P = 0.0009). Men showed larger stress responses in ACTH (P = 0.004), salivary free cortisol (P = 0.044), and plasma total cortisol (P = 0.076) compared to women. No sex differences were observed in norepinephrine, epinephrine, or heart rate responses. In contrast to ACTH and cortisol response differences, women reported that they were significantly more stressed by the TSST than men (P = 0.0051). Women treated with DHEA showed ACTH stress responses similar to those of men, but significantly enhanced compared to those of women taking placebos (P < 0.009). No other stress response differences emerged between DHEA and placebo groups. Finally, DHEA treatment did not result in an improvement of subjective well-being. We conclude that elderly men show larger HPA responses than women to psychosocial stress, as studied in the TSST. Estrogen effects on hypothalamic CRF-producing neurons might be responsible for these sex differences.     

Relation of race, age, and sex hormone differences to serum leptin concentrations in children and adolescents

We explored the effects of race, age, and sex hormones on the serum leptin concentrations in 203 white and 88 black children and adolescents (ages 9.3-20.5 years). A significant sex by race interaction on serum leptin levels (p = 0.0301) was observed with lower serum leptin concentrations, adjusted for subscapular thickness and age, in black boys than in white boys. Girls had serum leptin levels that were on average 2.15 times those of boys (p < 0.0001). There was an age by sex interaction (p < 0.0001) with serum leptin concentrations decreasing in boys but not in girls with age. A strongly inverse relationship of serum testosterone levels with serum leptin levels in boys (p = 0.0067) appeared to explain this effect of age. In conclusion, the serum leptin concentration is slightly lower in black boys. A higher testosterone level in boys appears to account for an age-related decline in serum leptin in boys and the overall lower levels in boys than in girls.     

Fecundity of sealworm (Pseudoterranova decipiens) infecting grey seals (Halichoerus grypus) in the Gulf of St. Lawrence, Canada: lack of density-dependent effects

Uterine egg counts were determined by means of an electronic particle counter in individual female sealworm, Pseudoterranova decipiens (Nematoda: Ascaridoidea: Anisakidae) collected from grey seals (Halichoerus grypus) from Anticosti Island, northern Gulf of St. Lawrence, in August and September 1992. Mean number of eggs per female was 54,916.9 (+/- 51,866.4), with a maximum of 300,000. Egg counts were strongly correlated with worm length, and less so with host sex and age, sealworm sex ratio, and densities of Anisakis simplex and Phocascaris sp. No effect of sealworm density on worm egg counts was determined and competitive effects by Contracaecum osculatum on sealworm fecundity were not observed. Analyses demonstrated that variation in sealworm fecundity was greater among seal hosts within groups than between groups for host age and sex, density of sealworm, and density of C. osculatum. No evidence for density-dependent regulation of sealworm fecundity could be found. Variations in worm egg counts are attributed to individual host effects on worm growth and fecundity.