Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Daniel Spratt is active.

Publication


Featured researches published by Daniel Spratt.


The Journal of Clinical Endocrinology and Metabolism | 2012

Mid-Gestational Maternal Free Thyroxine Concentration and Offspring Neurocognitive Development at Age Two Years

Wendy Y. Craig; Walter C. Allan; Edward M. Kloza; Andrea Pulkkinen; Susan E. Waisbren; Daniel Spratt; Glenn E. Palomaki; Louis M. Neveux; James E. Haddow

CONTEXT Lower neurocognitive development scores at age 2 yr have been reported in association with euthyroid hypothyroxinemia during early pregnancy. OBJECTIVE The objective of this study was to further explore this association with euthyroid hypothyroxinemia during early pregnancy. DESIGN This was an observational, nested case-control study. SETTING The study was conducted at physician offices and prenatal clinics throughout Maine. STUDY SUBJECTS Between May 2004 and March 2006, TSH was measured in 5734 women in conjunction with second-trimester Down syndrome screening. After completion of pregnancy, free T(4) was measured in stored second-trimester sera from euthyroid women (TSH 0.1-3.5 mIU/ml; n = 5560). Women with free T(4) at the third centile or less (n = 99) were matched with women whose free T(4) was at the 10th to the 90th centile (n = 99). INTERVENTIONS There were no interventions. MAIN OUTCOME MEASURE Bayley Scales of Infant Development (BSID III) were administered to the 198 offspring at age 2 yr. Scores for cognitive, language, and motor development were compared between matched pairs of offspring from the two groups before and after correcting for relevant variables. RESULTS Unadjusted BSID-III scores (cognitive, language, and motor) were lower by about 3% at age 2 yr among offspring of 98 hypothyroxinemic women (cases), reaching borderline significance for cognitive and motor scores. After adjustment for gestational age, the childs age at testing, maternal weight, and education, all differences diminished and became nonsignificant. Scores less than 85 were more frequent among case children but did not reach statistical significance (P = 0.14). CONCLUSIONS Isolated hypothyroxinemia during the second trimester is not associated with significantly lower BSID-III scores at age 2 yr, compared with scores for offspring of matched euthyroxinemic women.


Journal of Clinical Investigation | 1988

Effects of decreasing the frequency of gonadotropin-releasing hormone stimulation on gonadotropin secretion in gonadotropin-releasing hormone-deficient men and perifused rat pituitary cells.

Joel S. Finkelstein; Thomas M. Badger; Louis St. L. O'dea; Daniel Spratt; William F. Crowley

The effects of decreasing the frequency of pulsatile gonadotropin-releasing hormone (GnRH) stimulation on pituitary responsiveness were studied in (a) men with isolated GnRH deficiency who had achieved normal sex steroid levels during prior long-term pulsatile GnRH replacement and (b) perifused dispersed pituitary cells from male rats in the absence of sex steroids. In three groups of four GnRH-deficient men, the frequency of GnRH stimulation was decreased at weekly intervals from (a) every 2-3-4 h (group I), (b) every 2-8 h without testosterone replacement (group II), or (c) every 2-8 h with testosterone replacement (group III). In three groups of three columns of perifused dispersed pituitary cells, pulses of GnRH were administered every 2, 4, or 8 h. In groups I and II, mean area under the luteinizing hormone (LH) curve increased (P less than 0.025) and serum testosterone levels fell (P less than 0.035) as the frequency of GnRH stimulation was decreased. In group III, the area under the LH curve also increased (P less than 0.01) although serum testosterone levels were constant, thereby demonstrating that the increase in pituitary responsiveness to slow frequencies of GnRH stimulation occurs independently of changes in the sex steroid hormonal milieu. The area under the LH curve also increased in the perifused dispersed rat pituitary cells when the frequency of GnRH administration was decreased to every 8 h (P less than 0.05), thus demonstrating that the enhanced pituitary responsiveness to slow frequencies of GnRH stimulation is maintained even in the complete absence of gonadal steroids. Nadir LH levels fell in all three groups (P less than 0.01) as the frequency of GnRH stimulation was decreased. In contrast, mean peak LH levels, the rate of LH rise, and the rate of endogenous LH decay were constant as the frequency of GnRH stimulation was decreased. Finally, as the GnRH interpulse interval increased, mean LH levels fell, and mean follicle-stimulating hormone levels were stable or fell. These results indicate that (a) pituitary responsiveness to GnRH increases at slower frequencies of GnRH stimulation in models both in vivo and in vitro, (b) these changes in pituitary responsiveness occur independently of changes in gonadal steroid secretion, and (c) the increases in LH pulse amplitude and area under the curve at slow frequencies of GnRH stimulation are due to decreases in nadir, but not peak, LH levels. Slowing of the frequency of GnRH secretion may be an important independent variable in the control of pituitary gonadotropin secretion.


Fertility and Sterility | 2009

Stimulation of spermatogenesis with recombinant human follicle-stimulating hormone (follitropin alfa; GONAL-f®): long-term treatment in azoospermic men with hypogonadotropic hypogonadism

Alvin M. Matsumoto; Peter J. Snyder; Shalender Bhasin; Kathryn A. Martin; Thomas J. Weber; Stephen J. Winters; Daniel Spratt; Jim Brentzel; Louis St. L. O'dea

OBJECTIVE To demonstrate the efficacy and safety of follitropin alfa administered with hCG on spermatogenesis in adult male hypogonadotropic hypogonadism (HH) patients. DESIGN Phase III, multicenter, open-label, noncomparative. SETTING Seven US medical centers. PATIENT(S) A total of 36 adult males with severe HH. INTERVENTION(S) A total of 1,000 U hCG on alternate days for 3 to 6 months, with dose adjustments after 2 months, if necessary, to normalize T levels, followed by follitropin alfa 150 U and hCG on the same alternate days for 18 months, with dose adjustments as necessary. MAIN OUTCOME MEASURE(S) Proportion of patients with sperm density > or =1.5 x 10(6)/mL. Pubertal advancement and long-term safety and tolerability were also evaluated. RESULT(S) In total, 22 of 29 patients (75.9%) who received > or =1 dose of follitropin alfa and 20 of 25 patients (80%) who completed 18 months of hCG + follitropin alfa treatments achieved a sperm concentration > or =1.5 x 10(6)/mL. A sperm concentration >20 x 10(6)/mL was achieved by 8 of 29 men (27.5%). Median sperm concentration at 18 months was 5.2 x 10(6)/mL. Pubertal development continued during the study, and testis volumes increased. Five clinical pregnancies were achieved. Acne (52% of patients) was the most common side effect, and gynecomastia was reported in 10% of patients. CONCLUSION(S) Long-term treatment of azoospermic HH men using follitropin alfa and hCG is effective for stimulating spermatogenesis and is well-tolerated.


American Journal of Kidney Diseases | 1994

Kt/V, Nutritional Parameters, Serum Cortisol, and Insulin Growth Factor-1 Levels and Patient Outcome in Hemodialysis

Jonathan Himmelfarb; Diane Holbrook; Ellen McMonagle; Rosalind Robinson; Linda Nye; Daniel Spratt

Despite many technical advances in dialysis care, morbidity and mortality in chronic hemodialysis patients in the United States remains high. In this study, we analyzed the effects of Kt/V, nutritional parameters (serum albumin level, triceps skin-fold thickness, mid-arm muscle circumference, and normalized protein catabolic rate), and predialysis serum cortisol and insulin growth factor-1 levels on predicting morbidity and mortality. The cohort studied consisted of 52 patients recruited from a single outpatient dialysis facility. Cox proportional hazards modeling indicated that only Kt/V predicted subsequent mortality (P = 0.02), while both predialysis cortisol levels (P = 0.03) and Kt/V (P = 0.03) predicted hospitalization. Kaplan-Meier analysis demonstrated that the ability of cortisol levels to predict hospitalization was largely confined to the group with values greater than 22 micrograms/dL predialysis. High serum cortisol levels were correlated with low serum albumin levels and a trend toward low triceps skin-fold thickness and higher normalized protein catabolic rate, suggesting a catabolic state. Both predialysis serum cortisol and insulin growth factor-1 levels were higher than those in age- and sex-matched normal human controls. These results demonstrate the importance role of Kt/V in predicting subsequent hospitalization rates and mortality, and that high predialysis serum cortisol levels correlate with a high hospitalization rate.


Gynecologic Oncology | 1991

Vulvar leiomyomatosis in a patient with esophagogastric leiomyomatosis: Review of the syndrome

Kenneth Faber; Michael A. Jones; Daniel Spratt; Hector M. Tarraza

A case of vulvar leiomyomatosis in a young adult with a history of esophagogastrectomy as a child for esophagogastric leiomyomatosis is presented. The steroid receptor profile of the tumor is described. Therapy with a combination of gonadotropin suppression and surgery was undertaken. The literature pertaining to this rare combination is discussed.


American Journal of Physiology-endocrinology and Metabolism | 2008

Characterization of a prospective human model for study of the reproductive hormone responses to major illness

Daniel Spratt; Robert S. Kramer; Jeremy R. Morton; F. Lee Lucas; Karen Becker; Christopher Longcope

With critical illness, serum testosterone levels fall markedly, whereas estrogen levels rise. Although animal studies suggest adaptive advantages, no prospective model has been available for studies in humans. We hypothesized that coronary artery bypass graft (CABG) surgery would provide such a model by eliciting the same reproductive hormone and other endocrine responses as reported with major nonsurgical illnesses. We further hypothesized that those responses would occur consistently in all CABG patients with predictable time courses, providing reliable windows for prospective studies. In 17 men undergoing CABG, serum levels of reproductive hormones, cortisol, thyroid hormones, and IGF-I were measured before and for up to 5 wk after surgery. Changes in serum levels of reproductive and other hormones were similar to those reported in nonsurgical critically ill patients. Time course for onset, duration, and recovery of reproductive hormone changes were consistent among all patients. A window for studying the testosterone and estrogen responses was established as the first 5 days following CABG. Practical use of this model was demonstrated by evaluating, in another seven men, changes in gonadotroph responsiveness to GnRH following CABG. Finally, to determine whether our findings in CABG could be extended to other surgeries, we demonstrated similar endocrine responses in 12 men following abdominal aortic aneurysm resection. We conclude that patients undergoing CABG surgery provide a useful human model for the prospective evaluation of the reproductive axis responses to acute illness. Other major surgeries are likely to also be suitable for these studies.


The Journal of Clinical Endocrinology and Metabolism | 2017

Subcutaneous Injection of Testosterone Is an Effective and Preferred Alternative to Intramuscular Injection: Demonstration in Female-to-Male Transgender Patients

Daniel Spratt; India I. Stewart; Clara Savage; Wendy Y. Craig; Norman P. Spack; Donald Walt Chandler; Lindsey V. Spratt; Toni Eimicke; Jerrold S. Olshan

Context Testosterone (T) is commonly administered intramuscularly to treat hypogonadal males and female-to-male (FTM) transgender patients. However, these injections can involve significant discomfort and may require arrangements for administration by others. Objective We assessed whether T could be administered effectively and safely subcutaneously as an alternative to intramuscular (IM) injections. Design Retrospective cohort study. Setting Outpatient reproductive endocrinology clinic at an academic medical center. Patients Sixty-three FTM transgender patients aged >18 years electing to receive subcutaneous (SC) T therapy for sex transition were included. Fifty-three patients were premenopausal. Intervention Patients were administered T cypionate or enanthate weekly at an initial dose of 50 mg. Dose was adjusted if needed to achieve serum total T levels within the normal male range. Main Outcome Measurements Serum concentrations of free and total T and total estradiol (E2), masculinization, and surveillance for reactions at injection sites. Results Serum T levels within the normal male range were achieved in all 63 patients with doses of 50 to 150 mg (median, 75/80 mg). Therapy was effective across a wide range of body mass index (19.0 to 49.9 kg/m2). Minor and transient local reactions were reported in 9 out of 63 patients. Among 53 premenopausal patients, 51 achieved amenorrhea and 35 achieved serum E2 concentrations <50 pg/mL. Twenty-two patients were originally receiving IM and switched to SC therapy. All 22 had a mild (n = 2) or marked (n = 20) preference for SC injections; none preferred IM injections. Conclusions Our observations indicate that SC T injections are an effective, safe, and well-accepted alternative to IM T injections.


Annals of the New York Academy of Sciences | 1987

Approaches to the Study of GnRH in Humans: Implications for Design of Effective Therapies

William F. Crowley; Marco Filicori; Nanette Santoro; Daniel Spratt

Hypogonadotropic hypogonadism ( H H ) in both sexes has long been recognized as a diverse clinical syndrome, much to the distress of the clinician caring for such patients. Persistence of the prepubertal state with absence of secondary sexual characteristics represents the most obvious and severe form of the disorder in both sexes. Even at this end of the spectrum, however, variable clinical associations have been recognized, such as anosmia (Kallmann’s syndrome) and midline craniofacial defects.’.’ In addition, differing modes of inheritance have also been described’-’ in these disorders, further suggesting an underlying pathophysiological heterogeneity. Subjects with H H may also present postpubertally, with a history of subsequent regression of reproductive function. Although such a secondary regression of the hypothalamicpituitary-gonadal axis can occur in the male, this presentation occurs more typically in the female hypogonadotropic subject with hypothalamic amenorrhea. This latter circumstance is often associated with various precipitating factors such as weight lossp psychic stress,’.’ or, in women, excessive exercise. Moreover, these individuals may experience a spontaneous waxing and waning of the suppression of their hypothalamicpituitary-gonadal axes, such that their menses may often resume. As will be seen, this


Journal of the Endocrine Society | 2017

Aromatase Blockade Is Associated With Increased Mortality in Acute Illness in Male Mice

Jeannette Connerney; Daniel Spratt

Context: The increase in circulating estrogen levels with acute illness in humans is accompanied by increased aromatase expression in adipose tissue and increased peripheral aromatization of estrogens to androgens. Animal studies indicate that estrogen may be beneficial in acute illness. Objective: We hypothesized that blockade of aromatase in acute illness would decrease survival. Design: Prospective sham controlled. Setting: Maine Medical Center Research Institute animal facility. Animals: Six- to 8-week-old male black 6 mice. Intervention: Mice underwent cecal ligation and puncture (CLP) to induce acute illness and were administered letrozole to block aromatase or saline. Mice undergoing sham surgery with or without letrozole served as controls. Adipose and cardiovascular tissue was harvested for preliminary evaluation of aromatase expression. Main outcome measurements: Survival was the main outcome measurement. Evidence for aromatase expression in tissue samples was assessed using western blot and/or immunohistochemistry. Results: With aromatase blockade, survival in CLP mice was decreased (P = 0.04). The presence of aromatase in adipose tissue was observed by western blot in CLP but not control mice. Similarly, the presence of aromatase was observed in cardiac tissue of CLP but not in control mice. Conclusions: The decreased survival during sepsis with aromatase blockade suggests that this response to acute illness may be important both physiologically and clinically. The preliminary observation of aromatase expression in adipose and cardiovascular tissue during acute illness in this mouse model indicates that this model has parallels to human physiology and may be useful for further studying the aromatase response to acute illness.


Journal of the Endocrine Society | 2017

Serum Testosterone Concentrations Remain Stable Between Injections in Patients Receiving Subcutaneous Testosterone

Julie McFarland; Wendy Y. Craig; Nigel J. Clarke; Daniel Spratt

Purpose: Intramuscular (IM) testosterone is the most common modality for testosterone therapy of both male hypogonadism and female-to-male (FTM) gender transition. However, IM injections can be painful and often are not self-administered by the patient. The objective of this study was to further characterize subcutaneous (SC) administration of testosterone as an effective and safe alternative to IM injections by evaluating the pharmacodynamics of serum total and free testosterone concentrations between weekly testosterone injections. Methods: Eleven FTM transgender patients already receiving weekly SC testosterone cypionate with documented therapeutic levels prior to enrollment had free and total serum testosterone levels measured at eight different time points during a 1-week dosing interval. Results: Mean levels of total and free testosterone were stable and remained well within the normal range between injections. Overall mean ± standard deviation levels for the seven samples taken between injections were 627 ± 206 ng/dL (range, 205 to 1410) for total testosterone and 146 ± 51 pg/mL (range, 38 to 348) for free testosterone. No adverse effects were encountered. Conclusions: The results of this study support use of SC testosterone to achieve therapeutic and stable serum testosterone levels for the purpose of gender transition. It is anticipated that these results can be extended to hypogonadal men. This route may be preferred over IM testosterone because it is relatively painless and easy to self-inject thus allowing for the convenience and economy of patient self-administration.

Collaboration


Dive into the Daniel Spratt's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

P Cox

Maine Medical Center

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Christopher Longcope

University of Massachusetts Medical School

View shared research outputs
Top Co-Authors

Avatar

J Orav

Maine Medical Center

View shared research outputs
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge