Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study

Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different numbers (mean, 1.5 +/- 0.2 surges/mare); the internadir interval was 3.9 +/- 0.3 days. In contrast, mean FSH in women was low during the luteal phase and increased to a prolonged elevation during the follicular phase. The prolonged elevation was apparent in each individual (internadir interval, 15.2 +/- 0.4 days). Changes in LH or oestradiol concentrations encompassing deviation were not detected in mares, but both hormones increased slightly but significantly between emergence and deviation in women. The hypothesis that a greater number of growing follicles causes a greater predeviation decrease in FSH was supported for mares (r, -0.39; P< 0.04), but a similar negative correlation (r, -0.36) was not significant in women. The hypothesis that the increase in oestradiol during the luteal phase in women was at least partly attributable to luteal-phase anovulatory follicular waves was not supported. Normalization of FSH concentrations to the day of emergence showed maximum value on the day of emergence with a significant increase and decrease on each side of emergence in both species. The day of expected deviation occurred 3 days after emergence during the decline in FSH in both species. These results indicated that the previously reported striking similarities in emergence and deviation between mares and women during the ovulatory follicular wave are associated with species similarities in the temporal relationships between follicle events and FSH concentration changes. Thus, mares may be useful research models for studying the role and mechanism of the action of FSH in emergence and deviation during the ovulatory follicular wave in women.

Changes in steady-state concentrations of messenger ribonucleic acids in luteal tissue during prostaglandin F2α induced luteolysis in mares

Transvaginal ultrasound-guided luteal biopsy was used to evaluate the effects of prostaglandin (PG)F2alpha on steady-state concentrations of mRNA for specific genes that may be involved in regression of the corpus luteum (CL). Eight days after ovulation (Hour 0), mares (n=8/group) were randomized into three groups: control (no treatment or biopsy), saline+biopsy (saline treatment at Hour 0 and luteal biopsy at Hour 12), or PGF2alpha+biopsy (5mg PGF2alpha at Hour 0 and luteal biopsy at Hour 12). The effects of biopsy on CL were compared between the controls (no biopsy) and saline+biopsy group. At Hour 24 (12h after biopsy) there was a decrease in circulating progesterone in saline group to 56% of pre-biopsy values, indicating an effect of biopsy on luteal function. Mean plasma progesterone concentrations were lower (P<0.001) at Hour 12 in the PG group compared to the other two groups. The relative concentrations of mRNA for different genes in luteal tissue at Hour 12 was quantified by real time PCR. Compared to saline-treated mares, treatment with PGF2alpha increased mRNA for cyclooxygenase-2 (Cox-2, 310%, P<0.006), but decreased mRNA for LH receptor to 44% (P<0.05), steroidogenic acute regulatory protein to 22% (P<0.001), and aromatase to 43% (P<0.1) of controls. There was no difference in mRNA levels for PGF2alpha receptor between PG and saline-treated groups. Results indicated that luteal biopsy alters subsequent luteal function. However, the biopsy approach was effective for collecting CL tissue for demonstrating dynamic changes in steady-state levels of mRNAs during PGF2alpha-induced luteolysis. Increased Cox-2 mRNA concentrations suggested that exogenous PGF2alpha induced the synthesis of intraluteal PGF2alpha. Thus, the findings are consistent with the concept that an intraluteal autocrine loop augments the luteolytic effect of uterine PGF2alpha in mares.

Controlling interrelationships of progesterone/LH and estradiol/LH in mares

The interrelationships of progesterone, estradiol, and LH were studied in mares (n=9), beginning at the first ovulation (Day 0) of an interovulatory interval. An increase in mean progesterone concentrations began on Day 0 and reached maximum on Day 6, with luteolysis beginning on Day 14. A common progesterone threshold concentration of about 2 ng/ml for a negative effect on LH occurred at the beginning and end of the luteal phase. Progesterone and LH concentrations decreased at a similar rate from Day 6 until the onset of luteolysis on Day 14, consistent with a decreasing positive effect of LH on progesterone. Concentrations of LH during the increase in the ovulatory surge consisted of two linear regression segments involving a rate of 0.4 ng/ml/day for Days 14-22 and 1.8 ng/ml/day for Day 22 to 1 day after the second ovulation. The end of the first segment and beginning of the second segment was 2 days before ovulation and was the day the ovulatory estradiol surge was at a peak.

Rapid immunochromatography-based detection of mixed-species malaria infection in Pakistan

We report the identification of mixed Plasmodium infections in four recent patients with malaria clinically refractory to empiric chloroquine therapy using the rapid antigen detection kit, NOW ICT Malaria Pf/Pv. A rapid in vitro immunodiagnostic test, the NOW ICT Malaria Pf/Pv test kit was used for the detection of circulating Plasmodium falciparum (Pf) and Plasmodium vivax (Pv) antigens in whole blood. Peripheral blood microscopy confirmed mixed-species infection in all the cases. Thick and thin peripheral blood films were made and stained with Giemsa stain and examined by both hospital laboratory staff and an experienced parasitologist who was blinded to the results of the rapid malarial antigen tests. Four recent patients (all male; mean age, 24 years) with mixed malarial infection were identified. All the subjects were males working for an oil company in a coastal area of Pakistan, and all had been diagnosed presumptively with malaria based on clinical grounds (without microbiologic confirmation), and were treated empirically with chloroquine without clinical response. Semiquantitative malaria counts via microscopy were as follows: P. vivax, scanty (2 patients) and moderate (2 patients); for P. falciparum--scanty (1 patient), moderate (2 patients), and heavy (1 patient). The present case series, although limited by the small number of patients with proven mixed P. falciparum-P. vivax infection, highlights the usefulness of the rapid antigen test in a highly malarious region of Pakistan where chloroquine resistance is prevalent. Although there was full concordance between the results of blood smear microscopy and rapid antigen testing, these techniques are potentially most useful when there is a discrepancy with microscopy findings. Accurate and rapid diagnosis of parasites, particularly in cases of mixed P. falciparum and P. vivax infection, is of immense importance for individual patient management and in reducing the burden of disease, especially in regions of chloroquine resistance.

Regulation of circulating gonadotropins by the negative effects of ovarian hormones in mares

The functional and temporal relationships between circulating gonadotropins and ovarian hormones in mares during Days 7-27 (ovulation = Day 0) was studied using control, follicle ablation, and ovariectomy groups (n = 6 mares/group). In the follicle-ablation group, all follicles > or = 6 mm were ablated on Day 7, and every 2 days thereafter, newly emerging follicles were also ablated. Estradiol concentrations decreased (P < 0.01) similarly in the controls and the follicle-ablation group between Days 7 and 11 and by Day 15 began to increase in the controls and continued to decrease in the follicle-ablation group. Concentrations of progesterone were not affected by follicle ablation, but diameter of the corpus luteum was greater (P < 0.05) by Day 21 in the follicle-ablation group; these results indicated that the follicles were involved in morphologic luteolysis, but not in functional luteolysis. Concentrations of LH were higher (P < 0.05) on Days 15 and 16 in the follicle-ablation group than in the controls, indicating an initial negative effect of follicles on LH. Immunoreactive inhibin and estradiol decreased (P < 0.0001) and FSH and LH increased (P < 0.05) within 1 or 2 days after ovariectomy; these changes occurred more slowly in the follicle-ablation group. The maximum value for an FSH surge in each control mare was below the lower 95% confidence limit in the ovariectomy group. Maximum concentration for the periovulatory LH surge in the controls was not different from the mean maximum LH concentrations in the ovariectomy group. Our interpretation is that the gonadotropin surges resulted from changes in the magnitude of the negative effects of ovarian hormones on the positive effects of extraovarian control. There was no indication of a positive ovarian effect on either FSH or LH.

In vivo effects of pregnancy-associated plasma protein-A, activin-A and vascular endothelial growth factor on other follicular-fluid factors during follicle deviation in mares

During a follicular wave in mares, the two largest follicles (F1 and F2) begin to deviate in diameter when F1 is a mean of 22.5 mm. The intrafollicular effects of pregnancy-associated plasma protein-A (PAPP-A), IGF-I, activin-A and vascular endothelial growth factor (VEGF) on other follicular-fluid factors during deviation were studied. In four treated groups (n= 7/group), a single dose of one of the four factors was injected into F2 when F1 was ≥20.0 mm (expected beginning of deviation). In a control group (n= 7), F2 was injected with vehicle. One day after treatment, a sample of follicular fluid was taken from F1 and F2 of the control group and from F2 of the treated groups and was assayed for free IGF-I, oestradiol, androstenedione, activin-A, inhibin-A, follistatin and VEGF. In the control group, the means for all end points were significantly greater in F1 than in F2, except that concentrations of androstenedione were lower in F1 than in F2. The treatment effects for F2 were significant as follows: PAPP-A increased the concentrations of free IGF-I, inhibin-A, follistatin and VEGF and decreased the concentrations of androstenedione; IGF-I increased the concentration of inhibin-A and decreased the concentration of androstenedione; activin-A decreased the concentrations of follistatin and androstenedione and increased the diameter of F2; and VEGF increased the concentration of IGF-I and decreased the concentration of androstenedione. These results support the hypotheses that during deviation in mares PAPP-A increases the follicular-fluid concentrations of free IGF-I, follistatin responds to changes in follicular-fluid concentrations of activin-A, and VEGF affects the concentrations of other follicular-fluid factors.

Changes in vascular perfusion of the endometrium in association with changes in location of the embryonic vesicle in mares

The equine embryonic vesicle is mobile on Days 12-14 (Day 0 = ovulation), when it is approximately 9-15 mm in diameter. Movement from one uterine horn to another occurs, on average, approximately 0.5 times per hour. Mobility ceases (fixation) on Days 15-17. Transrectal color Doppler ultrasonography was used to study the relationship of embryo mobility (experiment 1) and fixation (experiment 2) to endometrial vascular perfusion. In experiment 1, mares were bred and examined daily from Day 1 to Day 16 and were assigned, retrospectively, to a group in which an embryo was detected (pregnant mares; n = 16) or not detected (n = 8) by Day 12. Endometrial vascularity (scored 1-4, for none to maximal, respectively) did not differ on Days 1-8 between groups or between the sides with and without the corpus luteum. Endometrial vascularity scores were higher (P < 0.05) on Days 12-16 in both horns of pregnant mares compared to mares with no embryo. In pregnant mares, the scores increased (P < 0.05) between Day 10 and Day 12 in the horn with the embryo and were higher (P < 0.05) than scores in the opposite horn on Days 12-15. In experiment 2, 14 pregnant mares were examined from Day 13 to 6 days after fixation. Endometrial vascularity scores and number of colored pixels per cross-section of endometrium were greater (P < 0.05) in the endometrium surrounding the fixed vesicle than in the middle portion of the horn of fixation. Results supported the hypothesis that transient changes in endometrial vascular perfusion accompany the embryonic vesicle as the vesicle changes location during embryo mobility.

An experimental model for amoebic abscess production in the cheek pouch of the Syrian golden hamster, Mesocricetus auratus

A new experimental model was developed in hamsters for amoebic abscess caused by Entamoeba histolytica. E. histolytica trophozoites were cultured in a liquid axenic medium, and then injected intradermally into the cheek pouch of the Syrian golden hamster, Mesocricetus auratus. Inoculation consistently resulted in abscess formation at the site in 20 of 22 (91%) study animals. The amoebic nature of the abscesses was confirmed by light microscopy and histopathologic examination. Abscess formation was maximal at day 12 post-inoculation. Potential applications of this simple and reliable model include further elucidation of the pathogenesis of invasive amoebiasis, studies of the host response to amoebae, and in vivo evaluation of chemotherapeutic agents that show in vitro efficacy against E. histolytica.

Interrelationships among follicles during the common-growth phase of a follicular wave and capacity of individual follicles for dominance in mares

The changing diameter interrelationships among follicles during the interval from emergence to deviation (common-growth phase) were studied in 59 mares. All follicles of ≥6.0 mm were ablated 10 days after ovulation. The four largest follicles of the postablation wave were ranked D1, D2, D3 and D4 at the expected beginning of deviation (D1 ≥ 20.0 mm), according to descending diameter. The four follicles were also ranked independently, according to order of emergence at 6.0–6.9 mm as E1 (first to emerge), E2, E3 and E4. The follicles emerged during 1.3 ± 0.1 to 3.1 ± 0.1 days, and expected deviation began 6.5 ± 0.1 days after ablation. The frequency of emerging follicles becoming the largest follicle at the beginning of deviation was different (P < 0.0001; chi-square test) among follicles E1 (61%), E2 (25%), E3 (9%) and E4 (5%). There were no differences in growth rates among the four follicles throughout the common-growth phase (overall, 2.8 ± 0.04 mm/day). The differences in diameters between follicles E1 and E2 were similar between 3 days (2.7 ± 0.2 mm) and 6 days (2.9 ± 0.4 mm) after ablation. In controls and after ablation of D1; D1 and D2; or D1, D2 and D3 at the expected beginning of deviation, the largest remaining follicle became dominant in 26 of 34 mares (76%). In 10 of 15 mares (67%), the second-largest follicle became dominant when the largest follicle was ablated 1 or 2 days after the expected beginning of deviation. Results indicated the following: 1) the first follicle to emerge maintained its diameter advantage in most mares and average diameter growth rates were similar among the four follicles throughout the common-growth phase; 2) the hypothesis was supported that the capacity for dominance is similar among the four largest follicles at the beginning of deviation, but dominance by a smaller follicle is blocked when a larger follicle is present; and 3) the second-largest follicle retained the capacity for dominance in most mares for as long as 2 days after the beginning of deviation.

Aberrant Blood Flow Area and Plasma Gonadotropin Concentrations During the Development of Dominant-Sized Transitional Anovulatory Follicles in Mares1

Color Doppler transrectal ultrasound was used to evaluate blood flow area in the wall of dominant anovulatory follicles versus ovulatory follicles in mares during the transition between anovulatory and ovulatory seasons. Daily examinations were done in 11 control mares toward the end of the anovulatory season. In 13 separate mares, follicular fluid was collected from 30-mm follicles, and blood flow areas from control mares were used as a basis for designating the sampled follicle as either anovulatory or ovulatory. Blood flow area in the controls ranged from 0.18 to 0.35 cm(2) in six mares on the day of a 30-mm anovulatory follicle and from 0.25 to 0.86 cm(2) in 11 mares on the day of a 30-mm ovulatory follicle; the ranges did not overlap except for one follicle. In the controls, mean blood flow area was lower (P < 0.05) in the anovulatory group than in the ovulatory group for each day beginning with the first Doppler examination at 25 mm. For plasma LH in controls, an effect of follicle group (P < 0.0001) and an interaction (P < 0.0001) of group by day reflected lower (P < 0.05) concentrations in the anovulatory group on Days -6, -2, and 5-8 (Day 0 = 30-mm follicle). For plasma FSH, an interaction (P < 0.0001) reflected higher (P < 0.05) concentrations in the anovulatory group on Days -3 and 1-4. More (P < 0.05) statistically identified FSH surges occurred in the anovulatory group during Days -7 to 8. In the sampled mares, follicular-fluid concentrations of estradiol, free insulin-like growth factor-1, inhibin-A, and vascular endothelial growth factor were lower (P < 0.05) in 30-mm designated anovulatory follicles than in 30-mm designated ovulatory follicles. Results were interpreted as follows: 1) The future anovulatory dominant-sized follicle developed under an LH deficiency, 2) the LH deficiency led to reductions in blood flow area and in concentrations of follicular-fluid factors, and 3) the reduction in follicle production of FSH suppressors resulted in higher plasma FSH concentrations.

Differential Blood Flow Changes Between the Future Dominant and Subordinate Follicles Precede Diameter Changes During Follicle Selection in Mares1

Diameter deviation during a follicular wave is characterized by the continued growth of the developing dominant follicle and reduced growth and regression of the subordinate follicles. This study considered the hypothesis that reduced blood flow in the future largest subordinate follicle precedes the beginning of diameter deviation. The hypothesis was tested by quantifying the daily changes in blood-flow velocities and blood-flow area within the wall of follicles before and during diameter deviation in mares (n = 7). The blood-flow end points were quantified daily by transrectal color Doppler ultrasonography. Follicles were identified retrospectively by rank as F1 (largest) and F2 according to the maximum attained diameter. Follicles were grouped into nine F1 diameter ranges of 3.0 mm each (equivalent to 1 day's growth) centered on 6.5, 9.5, 12.5, 15.5, 18.5, 21.5, 24.5, 27.5, and 30.5 mm. Diameter deviation began in the 24.5-mm group, as indicated by a smaller (P < 0.05) difference between F1 and F2 in the 24.5-mm group than in the 27.5-mm group. Based on a similar approach, peak systolic velocity and time-averaged maximum velocity of blood flow began to deviate between F1 and F2 in the 18.5-mm group (P < 0.04) and blood flow area began to deviate in the 21.5-mm group (P < 0.009). Thus, differential blood flow area between F1 and F2 began an average of 3.0 mm (equivalent to 1 day) and differential blood-flow velocities began an average of 6.0 mm before the beginning of diameter deviation. The results demonstrated that deviation between F1 and F2 in the blood flow of the follicle walls occurred 1 or 2 days before deviation in follicle diameter during follicle selection in mares.

Critical Role of Insulin-Like Growth Factor System in Follicle Selection and Dominance in Mares1

The role of the insulin-like growth factor (IGF) system in the deviation in growth rates among follicles (follicle selection) was studied in mares using an IGF binding protein (BP) to reduce the follicular-fluid concentrations of IGFs. The future dominant follicle (F1) was treated by intrafollicular injection at the expected beginning of deviation (F1 > or = 20 mm; Day 0). The experimental groups were control (no injection, n = 8), vehicle (injection of vehicle; n = 6), and BP (injection of 250 microg of recombinant human IGFBP-3; n = 6). A sample of follicular fluid was taken from F1 on Day 1 in all groups. Compared with the control group, IGFBP-3 reduced (P < 0.05) the follicular-fluid concentration of free IGF-1 by 90%; lowered (P < 0.05) the concentrations of estradiol, activin-A, inhibin-A, and vascular endothelial growth factor; and increased (P < 0.05) the concentration of androstenedione. The diameter of F1 decreased and the diameter of F2 increased after Day 0 in the BP group, compared with the control and vehicle groups. A greater (P < 0.05) increase in circulating concentrations of FSH between Days 0 and 1 occurred in the BP group than in the other groups and accounted for the increased growth of F2. Dominance and ovulation from F1 occurred from fewer (P < 0.03) mares in the BP group (1 of 6) than from the control and vehicle groups combined (11 of 14); the remaining mares in the BP group ovulated from F2. Results indicated that the IGF system has a critical intrafollicular role in the differential changes in concentrations of follicular-fluid factors between the future dominant and subordinate follicles, leading to the development of follicle dominance (selection) and ovulation in mares.

In vivo effects of an intrafollicular injection of insulin-like growth factor 1 on the mechanism of follicle deviation in heifers and mares

In cattle and mares, free insulin-like growth factor 1 (IGF-1) is higher in the future dominant follicle (F1) than in the future largest subordinate follicle (F2) before deviation in diameter or selection is manifested between the two follicles. The effect of IGF-1 on other follicular-fluid factors and on the destiny of F2 were studied in two experiments in each species, using a total of 40 heifers and 42 mares. An injection of IGF-1 was made into F2 at the expected beginning of deviation (heifers, F1 >or= 8.5 mm; mares, F1 >or= 20.0 mm; Hour 0). In heifers, follicular fluid was taken from F2 at Hours 3, 6, 12, or 24; each heifer was sampled only once. In mares, sequential F2 samples were taken from each mare at Hours 0, 6, and 24 or at Hours 12 and 24. Transvaginal ultrasound guidance was used for treatment and sample collection. In heifers, IGF-1 treatment of F2 stimulated the secretion of estradiol (P < 0.05) between Hours 3 and 6 and androstenedione (P < 0.05) between Hours 3 and 12. In F2 of control heifers, estradiol decreased (P < 0.05) and androstenedione did not change significantly. In mares, IGF-1 treatment of F2 did not affect the concentrations of estradiol during the 24-h posttreatment period; androstenedione decreased (P < 0.04) in the IGF-1 group and increased (P < 0.006) in the controls. Compared with control mares, the IGF-1 group had higher (P < 0.04) activin-A at Hours 12 and 24 and higher (P < 0.0006) inhibin-A at Hour 24. After ablating F1 at Hour 24 in mares, F2 became dominant and ovulated in more mares (P < 0.0002) in the IGF-1 group (12/14) than in the control group (2/14). These results are consistent with reported temporal relationships among follicular factors during deviation in both species and indicate that IGF-1 plays a key role in controlling the temporal relationships; however, no indication was found that IGF-1 stimulated estradiol production in mares during the 24 h after treatment.

Dose-response study of intrafollicular injection of insulin-like growth factor-I on follicular fluid factors and follicle dominance in mares

The effect of insulin-like growth factor-I (IGF-I) on the concentrations of follicular fluid factors during follicle deviation and the development of dominance was studied in mares in two experiments. Transvaginal ultrasound guidance was used for intrafollicular injection and subsequent sequential sampling of follicular fluid. Treatment involved a single injection of IGF-I into the second-largest follicle (F2) at the expected beginning of deviation (Hour 0) based on diameter (> or =20 mm) of the largest follicle (F1). Mares in IGF-I groups were given a dose of 500 microg (experiment 1) or 250, 25, or 2.5 microg (experiment 2). Ablation of F1 at Hour 24 was done in experiment 1, but not in experiment 2. The 500- and 250-microg doses stimulated growth, leading to ovulation of F2 in 10 of 10 and 4 of 5 mares in the two experiments, respectively, compared to 4 of 12 and 0 of 5 in saline-injected controls. These doses prevented (P < 0.05) the increase in IGF binding protein-2 and androstenedione that occurred in F2 of controls and increased (P < 0.05) the concentrations of activin-A, inhibin-A, and vascular endothelial growth factor (VEGF). The 500-microg dose stimulated higher (P < 0.05) concentrations of estradiol, but not until Hour 48, whereas the lower doses were ineffective. In experiment 2, free IGF-I concentrations in F2 at Hour 24 decreased progressively as the dose decreased so that concentrations for the 2.5-microg dose were higher (P < 0.05) than in F2 of controls and similar (not significantly different) to endogenous concentrations in F1. Correspondingly, concentrations of androstenedione in F2 at Hour 24 were lower (P < 0.05) and concentrations of activin-A, inhibin-A, and VEGF were higher (P < 0.05) after treatment of F2 with the 2.5-microg dose than in F2 of controls and were similar to concentrations in F1. Hence, a physiologic intrafollicular dose of IGF-I did not stimulate estradiol production but reduced the production of androstenedione and stimulated the production of activin-A, inhibin-A, and VEGF during follicle selection in mares.

Hormonal mechanism of follicle deviation as indicated by major versus minor follicular waves during the transition into the anovulatory season in mares

Follicle growth and circulating hormone concentrations were compared between an interovulatory interval and the first 60 days of the anovulatory season in pony mares. Daily observations were made from November of three groups: (i) ablation of follicles of >/=6 mm in diameter at day 10 after an ovulation that initiated an interovulatory interval, as determined retrospectively (ovulatory group, n=8), (ii) ablation at day 10 after the last ovulation of the year (anovulatory-10 group, n=6); and (iii) ablation at day 60 after the last ovulation of the year (anovulatory-60 group, n=6). Follicular waves were defined as major (dominant follicle) and minor (no dominant follicle). The percentage of mares with major waves after ablation for the ovulatory, anovulatory-10 and anovulatory-60 groups was 100, 33 and 0%, respectively, and the percentage with minor waves was 0, 67 and 100%, respectively. Minor waves were also detected in 83% of anovulatory mares between day 20 and day 60. Growth of the largest follicle was similar for major waves and minor waves but only until the beginning of deviation in the major waves. FSH surges after ablation were similar for all groups and for surges detected during days 20-60. Concentrations of LH were greater in association with major waves than with minor waves. Both diameter of the largest follicle and LH concentrations for minor waves were greater after ablation at day 10 after the last ovulation of the year than after ablation at day 60. The results of this study indicate that major follicular waves developed in some mares early in the anovulatory season and that minor waves developed throughout the first 2 months. Despite similarities in the wave-stimulating FSH surge, differences in follicle growth occurred and were attributable, on a temporal basis, to differences in LH concentrations. A minor wave developed into a major wave when the largest follicle reached a diameter characteristic of the beginning of deviation in the presence of an adequate LH stimulus for continued growth of a dominant follicle.

Hormonal mechanism of follicle deviation as indicated by major versus minor follicular waves during the transition into the anovulatory season in mares

Follicle growth and circulating hormone concentrations were compared between an interovulatory interval and the first 60 days of the anovulatory season in pony mares. Daily observations were made from November of three groups: (i) ablation of follicles of >/=6 mm in diameter at day 10 after an ovulation that initiated an interovulatory interval, as determined retrospectively (ovulatory group, n=8), (ii) ablation at day 10 after the last ovulation of the year (anovulatory-10 group, n=6); and (iii) ablation at day 60 after the last ovulation of the year (anovulatory-60 group, n=6). Follicular waves were defined as major (dominant follicle) and minor (no dominant follicle). The percentage of mares with major waves after ablation for the ovulatory, anovulatory-10 and anovulatory-60 groups was 100, 33 and 0%, respectively, and the percentage with minor waves was 0, 67 and 100%, respectively. Minor waves were also detected in 83% of anovulatory mares between day 20 and day 60. Growth of the largest follicle was similar for major waves and minor waves but only until the beginning of deviation in the major waves. FSH surges after ablation were similar for all groups and for surges detected during days 20-60. Concentrations of LH were greater in association with major waves than with minor waves. Both diameter of the largest follicle and LH concentrations for minor waves were greater after ablation at day 10 after the last ovulation of the year than after ablation at day 60. The results of this study indicate that major follicular waves developed in some mares early in the anovulatory season and that minor waves developed throughout the first 2 months. Despite similarities in the wave-stimulating FSH surge, differences in follicle growth occurred and were attributable, on a temporal basis, to differences in LH concentrations. A minor wave developed into a major wave when the largest follicle reached a diameter characteristic of the beginning of deviation in the presence of an adequate LH stimulus for continued growth of a dominant follicle.

Mechanism of follicle deviation in monovular farm species

Diameter deviation is a distinctive change in growth rates among the follicles of a wave, heralding the formation of a dominant follicle and subordinate follicles. When the follicles are about 5mm in cattle and 13 mm in horses, the wave-stimulating FSH surge reaches peak concentrations. Follicle and FSH manipulation studies in both species have shown that the declining portion of the surge before the beginning of deviation is a function of multiple growing follicles that require the decreasing FSH. During this time, all follicles of the wave have the potential for future dominance. Deviation begins when the two largest follicles on average are 8.5 and 7.7 mm in cattle and 22.5 and 19.0 mm in horses or about 3 days after the FSH peak in both species. The FSH/follicle relationship is close so that a change in one event soon causes a detectable change in the other. Thus, the difference in diameter between the two largest follicles at the beginning of deviation is compatible with rapid establishment of the destiny of the two follicles before the second-largest follicle can also show dominance. The deviation mechanism is initiated when FSH concentrations are low and the most advanced follicle reaches a specific developmental stage. In cattle, the future dominant follicle develops greater LH-receptor expression than the other follicles about 8 h before the beginning of diameter deviation. Estradiol and free IGF-1 begin to establish higher concentrations in the future dominant follicle than in other follicles and activin-A is transiently elevated in both follicles a few hours before the beginning of diameter deviation. In horses, estradiol, free IGF-1, activin-A, and inhibin-A begin to increase differentially in the future dominant follicle about 1 day before deviation. These changes underlie a greater responsiveness to LH and FSH by the developing dominant follicle than for other follicles, thereby accounting for deviation. Results of in vitro studies, although frequently done in other species, support this conclusion.

Role of oestradiol in growth of follicles and follicle deviation in heifers

Follicle deviation is characterized by continued growth of the largest (developing dominant) follicle and reduced growth of the smaller (subordinate) follicles. The aim of the present study was to test the following hypotheses: (1). oestradiol contributes to the depression of circulating FSH encompassing follicle deviation and (2). oestradiol plays a role in the initiation of deviation. Heifers were treated with progesterone (n = 5) or antiserum against oestradiol (n = 7) or given no treatment (control; n = 6). On the basis of previous studies, progesterone treatment would decrease LH and thereby the circulatory and intrafollicular concentrations of oestradiol and the antiserum would reduce the availability of oestradiol. Progesterone was given in six 75 mg injections at 12 h intervals beginning when the largest follicle of wave 1 first reached >or=5.7 mm (t = 0 h). Oestradiol antiserum (100 ml) was given in a single injection at t = 12 h. Follicles of the wave were defined as F1 (largest) and F2, according to the diameter at each examination. Blood samples were collected at 12 h intervals during t = 0-72 h. Treatment with progesterone lowered the circulatory concentrations of LH by 12 h after the start of treatment (P < 0.05), and concentrations remained low compared with those of controls during the treatment period. Treatment with oestradiol antiserum had no effect on LH. Both progesterone and the antiserum treatments increased the FSH concentrations compared with controls (P < 0.05), which supports the first hypothesis. The interval from t = 0 h to the beginning of deviation was longer in the progesterone- (51.0 +/- 7.6 h; P < 0.06) and antiserum (51.4 +/- 6.3 h; P < 0.05)-treated groups than in the controls (38.0 +/- 3.7 h), which supports the second hypothesis. There was no difference among groups in the diameters of F1 and F2 at deviation. Reduced diameter (P < 0.05 or P < 0.06) of both F1 and F2 occurred in both the progesterone- and antiserum-treated groups at t = 36 h and 48 h, compared with controls. Follicle retardation occurred in both the progesterone- and antiserum-treated groups despite the high FSH concentrations, whereas LH was altered only in the progesterone-treated group. Therefore, the follicle effect can be attributed to inadequate intrafollicular oestradiol. This interpretation implies a functional local role for oestradiol in the deviation process, independent of the systemic negative effect on FSH.

Calculated follicle deviation using segmented regression for modeling diameter differences in cattle

Segmented linear regression alone or in combination with simple linear regression was evaluated as an objective method to calculate the beginning of follicle deviation by modeling the sequential (Experiment 1) and non-sequential or single-point (Experiment 2) differences in diameter between the future dominant (F1) and largest subordinate (F2) follicles of Wave 1 in cattle. The segmented regression consisted of Segment 1 representing the common growth phase, Segment 2 representing the period of dominance, and a Join Point connecting the two segments and representing the end of the common growth phase and the beginning of deviation. The model was fit to the diameter differences for each heifer in Experiment 1 (n=15) and the group of heifers in Experiment 2 (n=40). The optimal Join Point value that corresponded to the maximum R(2) was designated the calculated hour (Experiment 1) or diameter of F1 (Experiment 2) at the beginning of deviation. In Experiment 1, simple linear regression was used to calculate the corresponding diameter of F1 at the beginning of deviation. Observed deviation was determined by inspection of the diameter profiles of F1 and F2 for comparison to calculated deviation. In Experiment 1, the observed method determined the beginning of deviation in 80% of the heifers, whereas, the regression method calculated deviation in 93% of the heifers including two of the three heifers in which observed deviation was not discernable (no significant difference between methods). The mean hours of deviation after wave emergence (Hour 0) and diameters of F1 at the corresponding hours were not significantly different between the observed (62 h and 8.4 mm) and calculated (61 h and 8.8 mm) methods. In Experiment 2, the diameter of F1 at the beginning of calculated deviation was 8.2 mm. The results indicated that the segmented regression model can provide an objective and more accurate alternative to estimate follicle deviation, especially when observed deviation is obscured by the complexity of follicle development in some waves.

Associated and independent comparisons between the two largest follicles preceding follicle deviation in cattle

Follicle diameters and concentrations of follicular fluid factors were studied in the two largest follicles (F1 and F2) using F1 diameters in increments of 0.2 mm (equivalent to 4 h intervals) and extending from 7.4 to 8.4 mm (12 heifers in each of 6 groups). Changes were compared between follicles using the F2 associated with each F1-diameter group. Diameter deviation began in the 8.2-mm group as indicated by a greater (P < 0.05) diameter difference between F1 and F2 in the 8.4-mm group than in the 8.2-mm group. In the 8.0-mm group, estradiol concentrations began to increase (P < 0.05) differentially in F1 versus F2, and free insulin-like growth factor-1 (IGF-1) began to decrease differentially in F2 (P < 0.06). Combined for F1 and the associated F2, activin-A concentrations increased (P < 0.05) between the 7.6- and 8.2-mm groups and then decreased (P < 0.05). Results supported the hypothesis that estradiol and free IGF-1 concentrations simultaneously become higher in F1 than in the associated F2 by the beginning of diameter deviation. Results did not support the hypothesis that a transient elevation in activin-A is present in F1 but not in the associated F2 at the beginning of the estradiol and IGF-1 changes; instead, a mean transient elevation in activin-A occurred at this time only when data for the two follicles were combined. Comparisons between F1 and F2 also were made by independently grouping F2 and using diameter groups at 0.2-mm increments for F2 as well as for F1. In the diameter groups common to F1 and F2 (7.4, 7.6, 7.8, and 8.0 mm) there was a group effect (P < 0.003) for estradiol involving an increase (P < 0.05) beginning at the 7.6-mm group averaged over F1 and F2. For free IGF-1 concentrations, a fluctuation (a significant increase followed by a significant decrease) occurred independently in F1 between the 7.4- to 7.8-mm groups and independently in F2 between the 7.0- to 7.4-mm groups.

Role of low circulating FSH concentrations in controlling the interval to emergence of the subsequent follicular wave in cattle

The intervals between emergence of follicular waves 1 (first wave of an oestrous cycle) and 2, and between the associated FSH surges (surges 1 and 2), were studied in control (n = 7) and recombinant bovine (rb)FSH-treated (n = 7) heifers. The expected start of the deviation in follicle diameter between the two largest follicles of wave 1 was defined as the day on which the largest follicle reached 8.5 mm (day 0). In the control heifers, circulating concentrations of FSH decreased and oestradiol increased between day 0 and day 1.5 or day 2.0 in a reciprocal relationship. The opposite reciprocal relationship between an FSH increase and an oestradiol decrease occurred during the next 3 days. This temporal result is consistent with a negative systemic effect of oestradiol on FSH at this time. rbFSH was administered in a dosage regimen that was expected to result in a similarity between FSH surge 2 in the rbFSH-treated group and surge 2 in the control group. On average, surge 2 and wave 2 occurred approximately 2 days earlier in the rbFSH-treated group than in the control group, and characteristics of the FSH surge and follicular wave were similar (no significant differences) between groups. These results support the hypothesis that low circulating FSH concentrations after the deviation in follicle diameter control the interval to emergence of the subsequent follicular wave. However, in one of seven rbFSH-treated heifers, the largest follicle from the apparent stimulation of rbFSH reached only 5.7 mm; therefore, the possibility of involvement of additional mechanisms cannot be dismissed.

Role of low circulating FSH concentrations in controlling the interval to emergence of the subsequent follicular wave in cattle

The intervals between emergence of follicular waves 1 (first wave of an oestrous cycle) and 2, and between the associated FSH surges (surges 1 and 2), were studied in control (n = 7) and recombinant bovine (rb)FSH-treated (n = 7) heifers. The expected start of the deviation in follicle diameter between the two largest follicles of wave 1 was defined as the day on which the largest follicle reached 8.5 mm (day 0). In the control heifers, circulating concentrations of FSH decreased and oestradiol increased between day 0 and day 1.5 or day 2.0 in a reciprocal relationship. The opposite reciprocal relationship between an FSH increase and an oestradiol decrease occurred during the next 3 days. This temporal result is consistent with a negative systemic effect of oestradiol on FSH at this time. rbFSH was administered in a dosage regimen that was expected to result in a similarity between FSH surge 2 in the rbFSH-treated group and surge 2 in the control group. On average, surge 2 and wave 2 occurred approximately 2 days earlier in the rbFSH-treated group than in the control group, and characteristics of the FSH surge and follicular wave were similar (no significant differences) between groups. These results support the hypothesis that low circulating FSH concentrations after the deviation in follicle diameter control the interval to emergence of the subsequent follicular wave. However, in one of seven rbFSH-treated heifers, the largest follicle from the apparent stimulation of rbFSH reached only 5.7 mm; therefore, the possibility of involvement of additional mechanisms cannot be dismissed.

Follicle and endocrine dynamics during experimental follicle deviation in mares

Deviation during a follicular wave in mares begins when the largest follicle (F1) reaches a mean diameter of 22.5 mm and is characterized by continued growth of F1 to become the dominant follicle and regression of F2 to become the largest subordinate follicle. In the present study, F1 was ablated at the expected beginning of deviation (Hour 0) to provide a reference point for characterizing the intrafollicular changes preceding experimental deviation between F2 and F3. Diameters and concentrations of follicular fluid factors in F2 and F3 were determined in F1-ablated mares at Hours 0, 12, 24, 48, or 72 (n = 8 mares/group). Circulating FSH concentrations were greater (P < 0.05) in the Hour 72 ablation group than in controls 12 h after ablation and then progressively decreased. The diameters of F2 and F3 increased (P < 0.05) during Hours 0 to 24. Thereafter, F2 continued to increase but F3 did not, indicating that experimental deviation began at Hour 24. The diameter of F2 and circulating FSH concentration at Hour 24 were similar (P > 0.1) to the diameter of F1 and FSH concentration at Hour 0, respectively. A differential change between F2 and F3 was not detected in follicular fluid concentrations of estradiol, inhibin-A, and activin-A by the beginning of experimental deviation. However, estradiol was higher in F2 at Hours 0 and 12 and inhibin-A was higher in F2 throughout the experiment, and both factors could have been involved in experimental deviation. Free insulin-like growth factor-1 (IGF-1) increased (P < 0.05) in F2 beginning at Hour 12 and was higher (P < 0.05) in F2 than in F3 by the beginning of experimental deviation. Temporally, this result indicated that intrafollicular IGF-1 was involved in conversion of F2 from a destined subordinate follicle to a dominant follicle.

Cerebral involvement in benign tertian malaria

Although Plasmodium vivax usually causes benign uncomplicated malaria, it can occasionally result in severe disease with life-threatening, end-organ involvement generally seen with falciparum malaria. We report a case of cerebral malaria caused by P. vivax and review the literature on this subject.

Activin A, estradiol, and free insulin-like growth factor I in follicular fluid preceding the experimental assumption of follicle dominance in cattle

In cattle, the two largest follicles of a wave (F1, F2) begin to deviate into a dominant follicle and a subordinate follicle when F1 is a mean of 8.5 mm in diameter. After the beginning of deviation, F1 and F2 are diameter-defined dominant and subordinate follicles. Changes associated with the conversion of F2 into a future dominant follicle were studied by ablating F1 at the expected beginning of deviation (F1, 8.5 mm; Hour 0) and assessing the follicular-fluid factors in F2. Follicles were designated F1C and F2C in controls and F2A in F1-ablated heifers. Follicular-fluid collections were made at Hours 0, 4, 8, or 12 (n = 7 heifers per hour; fluid from F1C, F2C, and F2A; experiment 1) or at Hours 4, 6, 8, 10, or 12 (n = 9 heifers per hour; fluid from F2A; experiment 2). Postablation concentrations of circulating FSH increased (P < 0.05) between Hours 2 and 6. Diameter of F2A increased (P < 0.05) after Hour 8 in both experiments so that the diameter of F2A at Hours 10 or 12 was not different (P > 0.1) from the diameter of F1 at Hour 0. A transient elevation (P < 0.05) in follicular-fluid activin A occurred in F2A at Hour 8 in both experiments. Concentrations of estradiol (P < 0.05) and insulin-like growth factor I (IGF-I; P < 0.1) decreased in F2C by Hour 8. In F2A, the concentrations of both factors began to increase (P < 0.05) after Hours 4 or 8 so that there was no difference (P > 0.1) between F1C and F2A at Hour 12. Concentrations of IGF-I and IGF binding protein 2 (IGFBP-2) in F2A changed in opposite directions at the same hours. No differences between follicles were found for concentrations of progesterone, androstenedione, inhibin A, and inhibin B. The order of events in the conversion of a future subordinate follicle to a future dominant follicle was an increase in systemic FSH, a transient elevation in follicular-fluid activin A, and a simultaneous increase in follicular-fluid estradiol and restoration of an apparent growth-compatible balance of free IGF-I and IGFBP-2.

Follicle selection in cattle: dynamics of follicular fluid factors during development of follicle dominance

Follicle diameter deviation during follicular waves in cattle begins with a reduction in growth rates of developing subordinate follicles, in contrast to the maintenance of a constant growth rate by a developing dominant follicle. In experiment 1, the temporal changes encompassing deviation in concentrations of follicular fluid factors relative to one another in the three largest follicles (F1, F2, and F3) were studied. Follicular fluid samples were collected when F1 reached diameter ranges of 7.0-7.9, 8.0-8.9, 9.0-9.9, and 10.0-10.9 mm (n = 12 per range). The first increase (P < 0.05) in the difference between F1 and F2 for estradiol occurred at the 8.0- to 8.9-mm range, which was one range earlier than for diameter (P < 0.05). Free insulin-like growth factor (IGF)-1 concentrations in F1 were similar among diameter ranges, but concentrations in F1 were higher (P < 0.05) than in F2 for each range except 7.0-7.9 mm. Concentrations of free IGF-1 in F2 decreased (P < 0.05). No significant differences were detected in concentrations of progesterone, androstenedione, total inhibin, and inhibin-A. Averaged over follicles, inhibin-B decreased (P < 0.05) between the 8.0- to 8.9- and 10.0- to 10.9-mm ranges, and activin-A increased (P < 0.05) between the 7.0- to 7.9- and 9.0- to 9.9-mm ranges. However, no differences were found among follicles. In experiment 2, changes associated with the development of dominance by F2 were studied using ablation of F1 at the beginning of expected deviation (F1, 8.5 mm; Hour 0) as the reference point. Follicular fluid factors were compared at Hour 12 between F2 of a control group (F1 intact; n = 10) and an ablated group (F1 ablated; n = 10). Diameter (P < 0.02), estradiol (P < 0.001), free IGF-1 (P < 0.002), and progesterone (P < 0.003) were greater and IGF-binding protein-2 was lower (P < 0.01) in F2 of the ablated group at Hour 12. No differences were detected in concentrations of androstenedione, total inhibin, and inhibin-A. The results of the two experiments indicated, on a temporal basis, that intrafollicular changes in estradiol and the IGF system, but not in the inhibin/activin system, could account for a reported greater FSH responsiveness by the future dominant follicle than by the future subordinate follicles by the beginning of diameter deviation in cattle.

Follicle selection in monovular species

Follicle deviation is proposed to be the eminent event in follicle selection in monovular species. At deviation, the largest follicle establishes dominance apparently before the second-largest follicle can reach a similar diameter. In cattle, based on diameters of the two follicles at the beginning of deviation, the mechanism becomes established in <8 h. An FSH:follicle-coupling hypothesis has been supported as the essence of follicle selection. According to the hypothesis, the growing follicles cause the FSH decline from the peak of the wave-stimulating FSH surge until deviation, even though the follicles continue to require FSH (two-way functional coupling involving multiple follicles). During multiple-follicle coupling, inhibin is the primary FSH suppressant. Near the beginning of deviation, the largest follicle secretes increased estradiol, and apparently both estradiol and inhibin contribute to the continuing FSH decline; only the more-developed largest follicle is able to utilize the low FSH concentrations (single-follicle coupling). Deviation is encompassed by a transient elevation in LH in heifers and by a component, often distinct, of the long ovulatory LH surge in mares. In heifers, receptors for LH appear in the granulosa cells of the future dominant follicle about 8 h before the beginning of deviation. The LH stimulates the production of estradiol and insulin-like growth factor-1. These intrafollicular factors and perhaps others account for the responsiveness of the largest follicle to the low concentrations of FSH. The smaller follicles have not reached a similar developmental stage and because of their continued and close dependency on FSH become susceptible to the low concentrations. Thereby, follicle selection is established.

Follicle Selection in Cattle: Relationships among Growth Rate, Diameter Ranking, and Capacity for Dominance

Follicles of wave 1 were designated F1, F2, and so forth, according to descending diameter at the expected (F1, > or =8.2 mm) or observed beginning of deviation (Hour 0), as indicated by a reduction in growth rate of F2. During Hours -24 to 0 (experiment 1; n = 34 waves) and Hours -16 to 0 (experiment 2; n = 21), F1 and F2 grew in parallel (no significant differences). During Hours -16 to 0, growth rate was greater (P < 0.05) for F1 (1.4 +/- 0.1 mm/16 h) and F2 (1.0 +/- 0.1) than for F3 (0.6 +/- 0.1) and F4 (0.5 +/- 0.1). During Hours 0 to 16, growth rate was greater (P < 0.05) for F1 (1.4 +/- 0.2 mm/16 h) than for F2 (0.1 +/- 0.1), F3 (0.1 +/- 0.1), and F4 (0.1 +/- 0.2). In experiment 1, zero, one, two, or three largest follicles were ablated by aspiration of contents at Hour 0 (n = 7/group). For heifers with a single dominant follicle, the dominant follicle formed from the largest retained follicle more often when it was >7.0 mm (14 of 15) than when it was <7.0 mm (0 of 10). When the retained follicles were <7.0 mm, the first follicle to reach 7.0 mm became dominant in seven of eight heifers. Mean hour of observed deviation (occurring after Hour 0 in the ablation groups) increased progressively in groups with increasing number of ablated follicles. Plasma concentrations of FSH for groups with one, two, or three ablated follicles increased to a similar extent between Hours 0 and 12. Results supported the following: 1) during the 24 h before the beginning of deviation, small follicles grew more slowly than large follicles and the largest follicles grew in parallel; 2) after ablation of large follicles, the small retained follicles did not deviate until one reached a diameter characteristic of the beginning of deviation; 3) the potential for dominance at the expected beginning of deviation was greatest for the largest follicle and decreased progressively for the smaller follicles but only when the retained follicles were >7.0 mm; and 4) the three largest subordinate follicles began to deviate simultaneously.

Effect of LH on circulating oestradiol and follicular fluid factor concentrations during follicle deviation in cattle

Progesterone was used to reduce LH concentrations starting at the time when the largest follicle was > or = 5.7 mm in diameter or well before the expected start of follicle deviation (largest follicle > or = 8.5 mm in diameter). Plasma concentrations of LH, FSH and oestradiol were determined at 4 h intervals in control and progesterone-treated heifers (n = 8 per group). Concentrations of LH were lower (P < 0.05) in the progesterone-treated group, reflecting an absence of the transient increase in LH concentrations that encompasses follicle deviation. An increase in oestradiol and a continued decrease in FSH occurred at the start of follicle deviation in the control cows but not in the treated heifers. In a second experiment, follicular fluid of the two largest follicles of control and progesterone-treated heifers was sampled at the expected start of deviation (n = 8--10 per group). The concentrations of oestradiol, but not androstenedione and free insulin-like growth factor I (IGF-I), in follicular fluid were higher (P < 0.001) in the largest follicle than in the second largest follicle. Progesterone treatment reduced (P < or = 0.02) the concentrations of all three factors in follicular fluid and increased (P < 0.05) the concentrations of insulin-like growth factor binding protein 2 (IGFBP-2). These results confirm that oestradiol contributes to the continued decrease in FSH concentrations after the start of follicle deviation. Prevention of the transient LH increase, the oestradiol increase and the continued FSH decrease did not significantly alter the mean time or follicle diameters characteristic of expected follicle deviation. However, in some treated individuals (three of eight), the observed follicle deviation was delayed. In addition, these results indicate that the secretion of oestradiol into the circulation and the increase in oestradiol and IGF-I and decrease in IGFBP-2 concentrations in the follicular fluid at the start of deviation are functions of the transient increase in LH concentrations that encompasses follicle deviation.

Effect of LH on circulating oestradiol and follicular fluid factor concentrations during follicle deviation in cattle

Progesterone was used to reduce LH concentrations starting at the time when the largest follicle was > or = 5.7 mm in diameter or well before the expected start of follicle deviation (largest follicle > or = 8.5 mm in diameter). Plasma concentrations of LH, FSH and oestradiol were determined at 4 h intervals in control and progesterone-treated heifers (n = 8 per group). Concentrations of LH were lower (P < 0.05) in the progesterone-treated group, reflecting an absence of the transient increase in LH concentrations that encompasses follicle deviation. An increase in oestradiol and a continued decrease in FSH occurred at the start of follicle deviation in the control cows but not in the treated heifers. In a second experiment, follicular fluid of the two largest follicles of control and progesterone-treated heifers was sampled at the expected start of deviation (n = 8--10 per group). The concentrations of oestradiol, but not androstenedione and free insulin-like growth factor I (IGF-I), in follicular fluid were higher (P < 0.001) in the largest follicle than in the second largest follicle. Progesterone treatment reduced (P < or = 0.02) the concentrations of all three factors in follicular fluid and increased (P < 0.05) the concentrations of insulin-like growth factor binding protein 2 (IGFBP-2). These results confirm that oestradiol contributes to the continued decrease in FSH concentrations after the start of follicle deviation. Prevention of the transient LH increase, the oestradiol increase and the continued FSH decrease did not significantly alter the mean time or follicle diameters characteristic of expected follicle deviation. However, in some treated individuals (three of eight), the observed follicle deviation was delayed. In addition, these results indicate that the secretion of oestradiol into the circulation and the increase in oestradiol and IGF-I and decrease in IGFBP-2 concentrations in the follicular fluid at the start of deviation are functions of the transient increase in LH concentrations that encompasses follicle deviation.

Tropical pulmonary eosinophilia and filariasis in Pakistan

Filariasis is a major health problem in South Asia, particularly India, Sri Lanka and Bangladesh. Pakistan was presumed to be not affected. We report for the first time confirmed cases of tropical pulmonary eosinophilia (TPE) in indigenous patients as a result of infection with Wuchereria bancrofti. Following clinical examination, total leukocyte and eosinophil counts were recorded. Parasitological examinations included blood for microfilariae and stool and urine for eggs of intestinal parasites. Total immunoglobulin (Ig) E and specific antifilarial IgG were measured. Suspected cases of TPE were treated with diethylcarbamazine, 6 mg/kg for four weeks and were followed up to 2 and 4 weeks after treatment. Four persons fulfilled the criteria for TPE. Their response to treatment was marked with clinical improvement, reduction in eosinophil count and reduced titers of specific antifilarial antibodies. Two persons had W. bancrofti antigen in their sera confirmed by filariasis antigen detection test. Tropical pulmonary eosinophilia due to Wuchereria. bancrofti, although rare, is present in Pakistan.

Follicular-fluid factors and granulosa-cell gene expression associated with follicle deviation in cattle

Intrafollicular changes in the largest follicle (F1) and second-largest (F2) follicle were examined in relation to follicle diameter deviation. Deviation is characterized by continued growth of the largest follicle and the cessation of growth of the smaller follicles. Granulosa cells and follicular fluid were obtained from slaughterhouse ovaries (n = 95 pairs, experiment 1), and follicular fluid was collected in vivo (n = 28 heifers, experiment 2). Several ranges in the diameter of F1 were used to represent the progressive growth of the follicle. The diameter range with the first significant increase in the difference between F1 and F2 was determined for each end point and was used as an indicator of the sequence of events associated with diameter deviation. An increased difference for diameter and for estradiol concentration occurred (P: < 0.05) simultaneously at the 8.5- to 8.9-mm range in both experiments. In experiment 1, the increased difference between F1 and F2 in LH receptor (LHr) mRNA expression occurred (P: < 0.05) at the 8.0- and 8.4-mm range. In F2 of experiment 2, there was a progressive decrease (P: < 0.05) in free insulin-like growth factor (IGF)-1 and a progressive increase (P: < 0.05) in IGF binding protein (BP)-2 across the follicle-diameter ranges (7.5-11.2 mm). No differences were detected between F1 and F2 for 3beta-hydroxysteroid dehydrogenase mRNA expression in experiment 1 and testosterone, total inhibin, and dimeric inhibin-A concentrations in experiment 2. The results indicated that the acquisition of granulosa cell LHrs by F1, as indicated by increased LHr mRNA expression, occurred one diameter range before an increased difference between F1 and F2 for diameter or estradiol concentrations. On a temporal basis, it is concluded that LHr acquisition plays a role in the establishment of diameter deviation. In addition, the reduced growth of F2 may have involved the reduced bioavailability of IGF-1 in association with elevated IGFBPs.

Follicle selection in cattle: role of luteinizing hormone

The circulating concentrations of LH were reduced by administration of 50 mg of progesterone every 8 h for 72 h, beginning when the largest follicle was 6.0 mm (experiment 1; n = 10). Progesterone treatment prevented the transient increase in LH that accompanied deviation (partitioning into dominant and subordinate categories) in control heifers (n = 10). The reduced LH concentrations were associated with reduced growth of the largest follicle, beginning a mean of 31 h after deviation, but did not alter the time of deviation or the growth and regression of the second-largest follicle. In experiment 2, 0 mg (controls) or 50 mg of progesterone was given every 8 h for three injections, beginning when the largest follicle was 7.0 mm (predeviation group) or 9.0 mm (postdeviation group; n = 8 for each of the four groups). Blood samples from the jugular vein and follicular-fluid samples from the two largest follicles were taken 8 h after the last treatment when the largest follicle was a mean of 8.7 mm in the predeviation group and 10.8 mm in the postdeviation group. In the controls, follicular-fluid concentrations of estradiol and free insulin-like growth factor (IGF)-1 in the largest follicle and IGF binding protein (IGFBP)-2 in the second-largest follicle were higher (P: < 0.05) in the postdeviation group than in the predeviation group. Progesterone treatment lowered (P: < 0.006) the circulating LH concentrations to a similar extent in both groups. In the predeviation group, progesterone treatment did not have a significant effect on any of the characteristics of the largest follicle. In the postdeviation group, the largest follicle of the progesterone-treated heifers had significant reductions in diameter and in follicular-fluid concentrations of estradiol and free IGF-1. Follicular-fluid concentrations of immunoreactive inhibin were not different for any of the comparisons. The results supported the hypothesis that LH has a positive effect on diameter of the largest follicle but not until after the beginning of diameter deviation. In addition, the results indicated that LH is involved in the production of estradiol by the largest follicle and that free IGF-1 concentrations increase in the largest follicle during deviation.

Ovarian response and endocrine changes in buffalo superovulated at midluteal and late luteal stage of the estrous cycle: A preliminary report

A study was designed to determine whether superovulatory and endocrine responses in buffalo differ when gonadotropin treatment is initiated at midluteal and late luteal stages of the estrous cycle. Twenty-eight buffalo were randomized into 4 groups (A, B, C and D). Buffalo in Groups A and B (n = 8 each) were superovulated with Folltropin (total dose 25 mg) and Lutalyse. Treatments in Group A were initiated between Days 8 to 10 (midluteal group) and in Group B between Days 13 to 15 (late luteal group) of the estrous cycle. Buffalo in Groups C and D (n = 6 each) were not superovulated and served as controls. Blood samples from all groups of buffalo were collected daily for plasma progesterone and estradiol determinations. The number of corpora lutea (CL) and unovulated follicles was recorded (following per rectum palpations) 5 or 6 d post-estrus. Buffalo in Groups A and B exhibited estrus in larger proportions and earlier (49.33 +/- 3.82 h and 46.67 +/- 2.46 h, respectively) than the control Groups C and D (77.33 +/- 5.33 h and 78.0 +/- 3.83 h, respectively). Mean number of CL was higher in Group B (3.38 +/- 0.46) than in Group A (2.25 +/- 0.75), however,the difference was not significant (P > 0.05). Plasma progesterone concentrations on the day of treatment were higher in late luteal superovulated and control groups than in midluteal superovulated and control groups. In both Groups A and B progesterone levels were significantly related (r = 0.78,0.76; P < 0.05) to the number of CL palpated after the superovulatory estrus. Progesterone levels on the day of estimation of ovarian response were approximately 4 times higher in Groups A and B than in Groups C and D. Peak estradiol concentrations were approximately twice as high in superovulated groups as in control groups.

Activities of glycogen phosphorylase, alanine aminotransferase and aspartate aminotransferase in adult worms of Litomosoides carinii recovered from pyridoxine deficient cotton rats (Sigmodon hispidus)

This paper demonstrates that the activities of glycogen phosphorylase (GP), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are reduced in adult worms of the filarial nematode Litomosoides carinii recovered from pyridoxine-deficient cotton rats when compared to worms recovered from pyridoxine-sufficient controls. GP, ALT and AST activities were determined in adult worms L. carinii recovered from cotton rat hosts over a 20-week experimental period. Activities of GP, ALT and AST in the parasite showed a direct correlation with the dietary pyridoxine intake of their host. Throughout the experiment, enzyme activities were significantly lower (P < 0.001) in worms from rats fed a pyridoxine-free diet ad libitum that in worms from rats fed either a stock colony diet, a pyridoxine-free diet ad libitum with daily supplementation of 100 micrograms pyridoxine or limited amounts of pyridoxine-free diet with daily supplementation of 100 micrograms pyridoxine. The lower than normal activity of GP, ALT, AST and other enzymes dependent on the biologically active derivative of pyridoxine, the coenzyme pyridoxal-5-phosphate (PLP), interferes with the protein, carbohydrate and lipid metabolism of L. carinii and may in part cause the reduced establishment, development and growth of the parasite in pyridoxine-deficient hosts.

The host-parasite relationships in pyridoxine (vitamin B6) deficient cotton rats infected with Litomosoides carinii (Nematoda: Filaroidea)

This paper demonstrates that the establishment and growth of the filarial nematode parasite, Litomosoides carinii, is reduced in pyridoxine-deficient cotton rats. Young cotton rats were assigned to one of three dietary: vitamin B6-deficient cotton rats (B6-AL) were fed a pyridoxine-free diet ad libitum; pair-fed controls (B6 + PF) were fed the same amount of pyridoxine-free diet as animals in the deficient group and given daily oral supplements of 100 micrograms pyridoxine; and pyridoxine-sufficient controls (B6 + AL) were fed the pyridoxine-free diet ad libitum and supplemented daily with 100 micrograms pyridoxine. Half of each group was infected with 50 L3 of L. carinii by subcutaneous injection 8 weeks after the start of the experimental feeding period. B6-deficient cotton rats ate less (P < 0.001) and gained less weight (P < 0.001) than B6-supplemented controls. The levels of microfilaraemia in deficient animals, measured weekly throughout the experiment by taking blood smears, was significantly lower than in supplemented animals (P < 0.001). The deficient rats became latent for L. carinii at 20 weeks post-infection, whereas there was patent microfilaraemia in rats in the other dietary groups until the end of the experiment. Smaller (P < 0.001) and fewer (P < 0.05) adult worms were recovered from the pleural and abdominal cavities of deficient animals than from either pair-fed or sufficient controls at autopsy 28 week post-infection.

Embryogenesis in Litomosoides carinii from pyridoxine deficient cotton rats

Pyridoxine (vitamin B6) deficiency was induced in cotton rats which were then infected with the filarial parasite Litomosoides carinii. Embryogenesis was assessed microscopically in worms taken from pyridoxine deficient cotton rats and from various categories of control animals. Embryogenesis was retarded in worms from pyridoxine deficient hosts and more abnormal embryos were present in such worms than in those from control animals.

Renal function during ticrynafen therapy

526 patients with essential hypertension or congestive cardiac failure were treated with ticrynafen (250--500 mg/day) or hydrochlorothiazide (50--100 mg/day) for 6 weeks to 6 months. There was no appreciable effect on renal function, as measured by changes in blood urea nitrogen and serum creatinine levels. Both drugs exhibited similar antihypertensive activity and ability to control signs and symptoms of congestive cardiac failure. Side effects were mild and reversible. A notable difference is the marked reduction in serum uric acid in patients treated with ticrynafen, unlike the elevated urate levels occurring after treatment with hydrochlorothiazide.

The straight sinus

✓ The dura mater of the posterior cranial fossa of 86 adult human cadavers has been examined grossly after the injection of India ink through the confluence of sinuses in order to visualize the extent, communications, and tributaries of the straight sinus. Variations from the textbook description of formation by the union of the inferior sagittal sinus and the great cerebral vein are described and discussed.

Double straight sinus. Report of six cases

✓ The straight sinus was examined in 43 human cadavers. In 13.95% of the cadavers the straight sinus was double, being either median in position, that is, one was superior and the other inferior (9.3%), or paramedian, that is, both lay side by side on either side of the midline at the junction of the falx cerebri with the tentorium cerebelli (4.65%).