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Biomedical subjects

Mary M Lee

Publications and source records attributed to Mary M Lee.

14 recordsLinked to original sources
PubMed2005

Triploid mosaicism in a 45,X/69,XXY infant.

We report on an infant referred for chromosome analysis during the neonatal period due to ambiguous genitalia. The genitalia appeared male with bilaterally palpable testes, penoscrotal hypospadias, chordee, and a bifid scrotum. Chromosome analysis and interphase FISH analysis of lymphocytes showed a 45,X karyotype and no evidence for SRY in 200 nuclei examined, respectively. Subsequent chromosome analysis of fibroblasts revealed a 69,XXY karyotype. Molecular studies were carried out to determine the etiology of the chromosome findings. Results indicated that the two cell lines are mosaic rather than chimeric and that the triploidy resulted from delayed dispermy rather than delayed polar body inclusion. To our knowledge this is the first reported living individual with (near) diploid/triploid mosaicism for 45,X/69,XXY.

Abnormalities, Multiple↗
PubMed2005

Predictors of serum dioxin levels among adolescent boys in Chapaevsk, Russia: a cross-sectional pilot study.

BACKGROUND: Toxicological studies and limited human studies have demonstrated associations between exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) and adverse developmental and reproductive health effects. Given that children may be particularly susceptible to reproductive and developmental effects of organochlorines, and the paucity of information available regarding childhood exposures to dioxins in particular, we undertook a pilot study to describe the distribution of, and identify potential predictors of exposure to, dioxin-like compounds and dioxins among adolescent boys in Chapaevsk, Russia. The pilot study was also designed to guide the development of a large prospective cohort study on the relationship of exposure to PCDDs, PCDFs, and PCBs with growth and pubertal development in peri-pubertal Chapaevsk boys. METHODS: 221 boys age 14 to 17 participated in the pilot study. Each of the boys, with his mother, was asked to complete a nurse-administered detailed questionnaire on medical history, diet, and lifestyle. The diet questions were used to measure the current and lifetime consumption of locally grown or raised foods. Blood samples from 30 of these boys were sent to the Centers for Disease Control and Prevention (CDC) for analysis of dioxins, furans and PCBs. RESULTS: The median (25th, 75th percentile) concentrations for total PCDDs, PCDFs and coplanar PCBs were 95.8 pg/g lipids (40.9, 144), 33.9 pg/g lipids (20.4, 61.8), and 120 pg/g lipids (77.6, 157), respectively. For WHO-TEQs, the median (25th, 75th percentile) for total PCDDs, PCDFs, and coplanar PCBs were 0.29 (0.1, 9.14), 7.98 (5.27, 12.3), and 7.39 (4.51, 11.9), respectively. Although TCDD was largely non-detectable, two boys had high TCDD levels (17.9 and 21.7 pg/g lipid). Higher serum levels of sum of dioxin-like compounds and sum of dioxin TEQs were positively associated with increased age, consumption of fish, local meats other than chicken, PCB 118, and inversely with weeks of gestation. CONCLUSION: The total TEQs among Chapaevsk adolescents were higher than most values previously reported in non-occupationally exposed populations of comparable or even older ages. Dietary consumption of local foods, as well as age and weeks of gestation, predicted dioxin exposure in this population.

Adolescent↗
PubMed2004

Pubertal and adult Leydig cell function in Mullerian inhibiting substance-deficient mice.

Mullerian inhibiting substance (MIS) causes Mullerian duct regression during sexual differentiation and regulates postnatal Leydig cell development. MIS knockout (MIS-KO) mice with targeted deletions of MIS develop Leydig cell hyperplasia, but their circulating androgen concentrations are reportedly unaltered. We compared reproductive hormone profiles, androgen biosynthesis, and the expression of key steroidogenic and metabolic enzymes in MIS-KO and wild-type (WT) mice at puberty (36 d) and sexual maturity (60 d). In pubertal animals, basal testosterone and LH concentrations in plasma were lower in MIS-KO than WT mice, whereas human chorionic gonadotropin-stimulated testosterone concentrations were similar. In adults, basal LH, and both basal and human chorionic gonadotropin (hCG)-stimulated testosterone concentrations were similar. Purified Leydig cells from pubertal MIS-KO mice had lower testosterone but higher androstanediol and androstenedione production rates. In contrast, testosterone, androstanediol, and androstenedione production rates were all lower in adult MIS-KO Leydig cells. Steroidogenic acute regulatory protein expression was lower in pubertal MIS-KO mice compared with WT, whereas 17beta-hydroxy-steroid dehydrogenase and 5alpha-reductase were greater, and P450c17 and P450scc were similar. The expression of steroidogenic acute regulatory protein and 17beta-hydroxysteroid dehydrogenase was lower in adult MIS-KO mice, whereas that of 5alpha-reductase, P450c17, and P450scc was similar. Collectively, these results suggest that in the absence of MIS, Leydig cells remain less differentiated, causing an altered intratesticular androgen milieu that may contribute to the infertility of MIS-KO mice. In immature mice, this deficit in steroidogenic capacity appears to be mediated by a direct loss of MIS action in Leydig cells as well as by indirect effects via the hypothalamic-pituitary-gonadal axis.

Age Factors↗
PubMed2003

MIS/AMH in the assessment of cryptorchidism and intersex conditions.

Mullerian inhibiting substance (MIS), also known as anti-Mullerian hormone (AMH), causes Mullerian duct involution during male sexual differentiation and also has a postnatal regulatory role in the gonads. Serum MIS/AMH has a gonad specific pattern of expression and its concentrations are sexually dimorphic in children; hence measurement of serum MIS/AMH helps in the evaluation of children with gonadal disorders. In boys with cryptorchidism (non-palpable gonads), serum MIS/AMH correlates with testicular tissue. A measurable value is predictive of undescended testes while an undetectable value is highly suggestive of anorchia. In minimally virilized phenotypic females, MIS/AMH helps differentiate between gonadal and non-gonadal causes of virilization. In children with intersex conditions, MIS/AMH values assist differential diagnosis: a value above the normal female range is predictive of testicular tissue, while an undetectable value is suggestive of absent testicular tissue. Thus, MIS/AMH is useful for delineating gonadal pathology and facilitates the differential diagnosis and management of children with diverse gonadal disorders.

Adolescent↗
PubMed2003

Müllerian-inhibiting substance inhibits rat Leydig cell regeneration after ethylene dimethanesulphonate ablation.

The postnatal development of Leydig cell precursors is postulated to be controlled by Sertoli cell secreted factors, which may have a determinative influence on Leydig cell number and function in sexually mature animals. One such hormone, Mullerian inhibiting substance (MIS), has been shown to inhibit DNA synthesis and steroidogenesis in primary Leydig cells and Leydig cell tumor lines. To further delineate the effects of MIS on Leydig cell proliferation and steroidogenesis, we employed the established ethylene dimethanesulphonate (EDS) model of Leydig cell regeneration. Following EDS ablation of differentiated Leydig cells in young adult rats, recombinant MIS or vehicle was delivered by intratesticular injection for 4 days (Days 11-14 after EDS). On Days 15 and 35 after EDS (1 and 21 days post-MIS injections), endocrine function was assessed and testes were collected for stereology, immunohistochemistry, and assessment of proliferation and steroidogenesis. Although serum testosterone and luteinizing hormone (LH) were no different, intratesticular testosterone was higher on Day 35 in MIS-treated animals. At both time points, intratesticular 5alpha-androstan-3alpha,17beta-diol concentrations were much higher than that of testosterone. MIS-treated animals had fewer mesenchymal precursors on Day 15 and fewer differentiated Leydig cells on Day 35 with decreased numbers of BrdU+ nuclei. Apoptotic interstitial cells were observed only in the MIS-treated testes, not in the vehicle-treated group on Day 15. These data suggest that MIS inhibits regeneration of Leydig cells in EDS-treated rats by enhancing apoptotic cell death as well as by decreasing proliferative capacity.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2003

The role of Müllerian inhibiting substance in the evaluation of phenotypic female patients with mild degrees of virilization.

Müllerian inhibiting substance (MIS) is a sexually dimorphic gonadal hormone with proven efficacy in the evaluation of boys with cryptorchidism and children with intersex conditions. We examined the role of MIS determination in the evaluation of 65 phenotypic females with mild virilization. Among the 28 subjects with MIS values elevated above the normal female range, all had abnormal gonadal tissue: ovotestes in 11, testes in 7, dysgenetic gonads in 7, and MIS-secreting ovarian tumors in 3. Among the 37 children with serum MIS in the normal female range, 19 had detectable MIS and 18 had unmeasurable MIS. In the former group with measurable but normal female MIS values, 16 subjects had ovaries, 1 had an ovotestis, and 1 had dysgenetic gonads containing testicular elements. Of 18 children with undetectable MIS values, 16 had ovaries and 2 had ovarian dysgenesis. In this study, elevation of serum MIS above the normal female range was consistently associated with the presence of testicular tissue or MIS- secreting tumors, mandating additional evaluation and surgical exploration. A value within the normal female range in a virilized patient did not exclude dysgenetic testicular tissue or ovotestis, whereas undetectable values were consistent with the absence of testicular tissue.

Adolescent↗
PubMed2003

Physical growth and sexual maturation of boys in Chapaevsk, Russia.

We characterized physical growth and sexual maturation in 2,579 boys, ages 10 through 16.99 years, residing in Chapaevsk, Russia in order to establish region-specific reference data. Age-specific norms were established for height, weight, and BMI, and compared to US reference data by z-score analysis, while mean heights and weights by age were compared to published national Russian data. Compared to US boys, height was slightly lower (overall z-score -0.18) at all ages except the oldest (16-16.99 yr), while weight and BMI were moderately lower (overall z-score -0.52 and -0.61, respectively). Chapaevsk boys were significantly taller (1.15 cm) and thinner (-1.28 kg) than the broader Russian sample. The median ages of stage 2 genitalia and pubic hair development were 11.9 and 12.7 years, respectively. In conclusion, Chapaevsk boys are thinner than both US and Russian boys, and have a later onset of puberty and attainment of sexual maturity than boys from other countries.

Adolescent↗
PubMed2002

Insulin pump therapy in toddlers and preschool children with type 1 diabetes mellitus.

OBJECTIVE: To test whether glycemic control in young children could be achieved more effectively and safely by using continuous insulin infusions administered by insulin pumps. STUDY DESIGN: We analyzed the effects of pump therapy in nine toddlers in whom type 1 diabetes developed between the ages of 10 and 40 months. After a mean of 13.7 months of therapy with multiple daily injections, patients were treated with insulin pumps for periods ranging from 7 to 19 months (mean, 12.7 months). RESULTS: Before initiation of pump therapy, HbA1c levels averaged 9.5% +/- 0.4%, and patients had a mean of 0.52 episodes per month of severe hypoglycemia (uncontrolled shaking, inconsolable crying, disorientation, or seizures). After initiation of pump therapy, HbA1c levels declined to 7.9% +/- 0.3% (P <.001 vs prepump levels), and the incidence of severe hypoglycemia decreased to 0.09 episodes per month (P <.05). Normal linear growth and weight gain were maintained during pump therapy. There were no changes in the frequency of physician or emergency room visits for acute hyperglycemia or ketoacidosis. However, the frequency of parental contacts with health personnel declined by >80%, reflecting increasing parental confidence and independence in diabetic care. Subjective assessments revealed significant improvements in quality of life and high levels of satisfaction with pump therapy. CONCLUSIONS: Insulin pump therapy may provide an effective alternative for selected preschool children with type 1 diabetes.

Child Welfare↗
PubMed2002

Measurement of Mullerian inhibiting substance facilitates management of boys with microphallus and cryptorchidism.

Mullerian inhibiting substance (MIS) is a gonadal hormone expressed in a sexually dimorphic pattern. In males, serum MIS reflects Sertoli cell function and provides an estimate of seminiferous tubular integrity. We examined the role of MIS determination in the evaluation of boys with microphallus (n = 62) and/or cryptorchidism (n = 156). MIS was normal in 69.2% of boys with isolated microphallus compared with 38.1% of boys with microphallus and coexisting cryptorchidism (P < 0.05). In the cryptorchid group, MIS was normal in 46.8%, low in 24.4%, and absent in 28.8%. Normal values for age were associated with testicular tissue, whereas undetectable values were indicative of anorchia, except for two boys with MIS gene mutations (persistent Mullerian duct syndrome). These data demonstrated that a basal MIS measurement is more specific and has a higher positive predictive value than stimulated testosterone values for ascertaining the absence of testes (anorchia). In summary, a normal serum MIS concentration in the prepubertal child is a reliable determinant of testicular tissue, whereas an undetectable value is a highly sensitive initial screening test for anorchia. We conclude that preoperative measurement of MIS facilitates the management of children with cryptorchidism and intersex disorders and offers a measure of Sertoli cell function.

Adolescent↗