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Biomedical subjects

M D Urban

Publications and source records attributed to M D Urban.

At least 19 recordsLinked to original sources
PubMed1998

Molecular investigation of two male subjects with short stature and a 45,X/46,X,ring(Y) karyotype.

We studied 2 subjects with a 45,X/46,X,ring(Y) karyotype. Both of them were evaluated because of short stature and a subnormal rate of linear growth. One patient had additional features of the Ullrich-Turner syndrome. Both subjects had normal male external genitalia. Two copies of the pseudoautosomal gene, MIC2, were present in DNA of each individual. All sequences examined on the Y-specific portion of the short arm, including those for the sex-determining region Y (SRY) gene, were present. By contrast, portions of the long arm of the Y chromosome were missing from DNA of both subjects. In subject 1, deletion intervals 6 and 7 were missing. In subject 2, deletion interval 5, distal to 5B, was missing in addition to intervals 6 and 7. The most likely explanation for the ring formation in these subjects is a chromosomal break in the long arm and in the pseudoautosomal region of the short arm distal to MIC2 with subsequent ligation of the remaining sequences on the long arm and short arm. However, a complex rearrangement cannot be excluded.

12E7 Antigen↗
PubMed1996

Abnormal gonadal differentiation in two subjects with ambiguous genitalia, Mullerian structures, and normally developed testes: evidence for a defect in gonadal ridge development.

Among a group of patients with abnormal sexual differentiation, we have identified two subjects who had a 46,XY karyotype, ambiguous genitalia, and well-developed Müllerian structures, but normal appearing testes. The presence of ambiguous genitalia and persistent Müllerian structures implied both Leydig cell and Sertoli cell dysfunction, hence, gonadal dysgenesis. However, the normal testicular histology suggested that the underlying abnormality was not a defect in testis determination itself but an abnormality in timing of gonadal ridge and testis development. In one of the two subjects genomic DNA was available. The sequence of the SRY gene was normal. Because rare patients with partial androgen insensitivity may have a similar phenotype, the AR gene was evaluated by denaturing gradient gel electrophoresis (DGGE) and was normal. Some subjects with mutation of the WT1 gene or with deletion of the distal short arm of chromosome 9 may have similar phenotypes. The WT1 gene was studied by single-strand conformation polymorphism (SSCP) analysis and was normal. In addition, there was no loss of heterozygosity of polymorphic markers in distal 9p. The gene for Müllerian inhibiting substance (MIS) was also studied by SSCP and was normal. Although the exact mechanism for the defect in the two subjects is unknown, it may be due to an abnormality in a gene or genes involved in the timing of gonadal ridge development.

Cell Differentiation↗
PubMed1992

Premature pubarche: etiological heterogeneity.

Premature pubarche is characterized by pubic hair, adult type body odor, acne, and axillary hair before 8 yr of age in girls and 9.5 yr of age in boys. Causes of this premature virilization include premature adrenarche, mild errors of steroidogenesis, precocious puberty, and adrenal and gonadal tumors. To determine whether any clinical parameters are helpful in distinguishing which children should undergo further evaluation for mild congenital adrenal hyperplasia, we performed ACTH stimulation tests in 69 children with premature pubarche and 8 pubertal controls. Patients were categorized as having typical (pubic hair with or without axillary hair and body odor) or atypical (pubic hair and genital enlargement) premature pubarche. Blood samples, before and 30 min after iv bolus administration of synthetic ACTH, were obtained for progesterone, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, 11-deoxycortisol, and cortisol measurements. The patients were divided into 4 groups based on their individual responses to ACTH stimulation: premature adrenarche (no apparent defect in steroidogenesis), possible decreased 21-hydroxylase activity, possible decreased 3 beta-hydroxysteroid dehydrogenase activity, and indeterminate responses. Five of 11 (45%) children with atypical premature pubarche and 7 of 58 (12%) children with typical premature pubarche were found to have evidence of mild defects in steroidogenesis. Similar to previous reports in postpubertal women, only responses to ACTH stimulation allowed accurate classification of these patients.

17-alpha-Hydroxypregnenolone↗
PubMed1991

New clinical aspects of hereditary mucoepithelial dysplasia.

Hereditary mucoepithelial dysplasia (HMD) is a multiepithelial disorder. It is transmitted as an autosomal dominant trait (McKusick: Mendelian Inheritance in Man-Catalogs of Autosomal Dominant, Autosomal Recessive, and X-Linked Phenotypes, 8th edition. Baltimore: The Johns Hopkins University Press, pp 499, 1988). HMD is characterized by variable combinations of lesions of skin, hair, orificial mucosa, gingiva, eyes, and lungs. In some previously described patients, the corneal and pulmonary lesions were progressive and led to blindness, recurrent pneumonia, and/or premature death. On light microscopy, the lesion is characterized by dyskeratosis, and, on electron microscopy, by a paucity of gap junctions and desmosomes. Here, we describe a new 5-generation kindred in which affected individuals had the same histologic characteristics but a somewhat different clinical spectrum and a more benign course. HMD should be considered in the differential diagnosis of childhood alopecia, follicular hyperkeratosis, keratoconjunctivitis, juvenile cataracts, gingival hyperemia, restrictive lung disease, and esophageal stenosis or webs.

Alopecia↗
PubMed1987

HCG stimulation in children with cryptorchidism.

Fifty-eight children with cryptorchidism have been given hCG stimulation testing, 31 with bilateral cryptorchidism, 22 with unilateral, and 5 with prior unsuccessful orchiopexy. Hormonal studies were carried out prior to and following stimulation. In bilateral cryptorchidism, bilateral descent was observed in 32 percent of cases and in unilateral, the success rate was 55 percent. From their data, the authors concluded that hCG is not indicated if patients present elevated LH and FSH levels or if the basal T levels are in the pubertal range. In the other subjects, the hCG test will permit the determination of the presence or absence of testosterone production and in some cases it results in testicular descent. Finally, in cases of failure that require surgery, the hCG will stimulate tissue growth enhancing the success of orchiopexy.

Adolescent↗
PubMed1982

Attenuated forms of congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

A variety of mild forms of congenital adrenal hyperplasia (CAH) due to partial 21-hydroxylase deficiency have recently been described. We report two families in whom members presented with CAH with various degrees of enzyme deficiency. In family A, two children had the classical salt-losing CAH. Their male sibling and mother presented a very mild asymptomatic form of CAH, characterized by elevated basal plasma levels of 17-hydroxyprogesterone (17-OHP) and exaggerated responses of progesterone and 17-OHP to ACTH stimulation. The Hormonal profile and HLA types of these two individuals suggested allelic compounds, having one mutant gene for classical CAH and another for a mild form. In family B, the proband presented an attenuated form of CAH, manifested by amenorrhea and hirsutism, elevated basal levels of plasma 17-OHP and androgens, as well as markedly increased ACTH response. Two of her four siblings had the same ad HLA type, elevated basal plasma 17-OHP levels, and increased ACTH response. Their father, their paternal aunt, and their paternal uncle had the ab HLA type and normal basal plasma 17-OHP but markedly increased ACTH response. The haplotypes a, b, and d were considered to be linked to a mutation resulting in mild 21-hydroxylase deficiency, the homozygotes with ab HLA type having a milder form of CAH than the homozygotes with the ad HLA type. The wide spectrum of clinical and hormonal characteristics among homozygotes for the 21-hydroxylase deficiency trait suggests that their is a continuum of degree of enzyme deficiency. Furthermore, it suggests that most nonclassical subjects are allelic compounds for variable degrees of severity in the mutation at the 21-hydroxylase locus. More specifically, the study of families A and B shows that the so-called cryptic and attenuated forms of CAH have the same pathophysiological basis.

Adolescent↗
PubMed1982

True hermaphroditism.

Eleven cases of true hermaphroditism (eight previously reported) studied at The Johns Hopkins Hospital are presented. The two most recently observed patients had what is to be considered an appropriate endocrine evaluation. This includes karyotyping, and measurement of 24-hour urinary 17-ketosteroids, gonadotropins, plasma testosterone, dihydrotestosterone, and all their precursors before and following a human chorionic gonadotropin stimulation test, and a sexual skin biopsy for androgen receptor binding and 5 alpha-reductase activity. The differential diagnosis of true hermaphroditism is discussed and an approach to gender assignment is presented.

17-Ketosteroids↗
PubMed1981

Intra-HLA recombinations localizing the 21-hydroxylase deficiency gene within the HLA complex.

Close linkage between HLA and the gene for 21-OH deficiency causing congenital virilizing adrenal hyperplasia (CVAH) has been well documented. HLA-A/B and HLA/GLO recombination data placed the CVAH gene within the HLA-A to GLO interval, with CVAH invariably segregating with HLA. HLA-A,B,C,DR and GLO typing and ACTH stimulation to determine carrier status was done on seven families. Carrier status correlated with the appropriate HLA haplotypes in all offspring, with two exceptions. Two intra-HLA recombinants were detected in one three-generation family. The father of the proband is homozygous for HLA-A2,Cw2,B27 but is a DR2/DR4 heterozygote. The CVAH gene segregated with DR2 in all but one of his offspring who is a carrier and is DR4. This finding is consistent with recombination between the CVAH gene and DR. Study of the father's family confirmed synteny of the CVAH gene and DR2. Three of four sibs of the father inherited this haplotype and were CVAH carrier, as was the paternal grandmother, whose other haplotype was A1, Bw44,DR1. One of the father's sibs was shown serologically to be a HLA-B/D maternal recombinant and a noncarrier. she inherited the A1,Bw44 of one maternal haplotype, but the DR2 of the other. In both recombinants in this family the CVAH gene segregated with the A to B interval, separate from D. While we cannot determine whether the CVAH gene is in the HLA-A to B or B to D interval, this is the first report of two intra-HLA recombinations in one family that unequivocally map the CVAH gene inside HLA-D.

Adrenal Hyperplasia, Congenital↗
PubMed1980

Treatment of Cushing's disease with bilateral adrenalectomy and autotransplantation.

2 Cases of childhood Cushing's disease have been treated with bilateral adrenalectomy and autotransplantation of adrenal tissue. Transplantation was unsuccessful in 1 case. In the other patient, replacement therapy was discontinued without any symptoms of hypo- or hyperadrenocorticism. Her urinary 17-hydroxycorticosteroids, free cortisol and aldosterone remain in the low normal range indicating functional adrenal tissue, probably a result of the transplant.

Adolescent↗
PubMed1980

Plasma progesterone, 17-hydroxyprogesterone, androstenedione and testosterone in prepubertal, pubertal and adult subjects with congenital virilizing adrenal hyperplasia as indicators of adrenal suppression.

To determine whether a single morning plasma level of 17-hydroxyprogesterone (17OH-P), androstenedione, testosterone and progesterone reflected the degree of control of 21-hydroxylase congenital virilizing adrenal hyperplasia (CVAH) as indicated by 24-hour urinary 17-ketosteroid and pregnanetriol excretion, 142 simultaneous 24-hour urine and morning blood collections were made from 65 patients with CVAH. Patients were grouped into five categories on the basis of age, skeletal age, and sex. Paired blood and urinary data were analyzed. The results suggest that androstenedione is the most reliable indicator for all patient categories. Testosterone is an excellent indicator for children of both sexes and for adolescent and adult females. Levels of 17OH-P are difficult to interpret, as they can be several fold higher than the normal values when adrenal suppression appears adequate on the basis of urinary data. In general, progesterone is a poor indicator.

17-Ketosteroids↗
PubMed1980

The attenuated form of congenital adrenal hyperplasia as an allelic form of 21-hydroxylase deficiency.

A 17-yr-old female presented with marked menstrual irregularities since menarche at age 13 yr and severe hirsutism, particularly facial, since puberty. Her disorder was shown to be related to a mild 21-hydroxylase deficiency and she was diagnosed to have an attenuated (so-called acquired) form of congenital virilizing adrenal hyperplasia. HLA typing and ACTH testing of her parents and siblings provided evidence of a linkage between HLA and 21-hydroxylase deficiency loci. Similar observations have been made previously for the salt-losing and simple virilizing forms of congenital virilizing adrenal hyperplasia, suggesting that these two as well as the attenuated forms are allelic in regard to the 21-hydroxylase deficiency gene.

Adolescent↗
PubMed1980

Androgens in pubertal males with Addison's disease.

The time of onset and progression of pubertal development has been documented in seven male patients with Addison's disease. Two patients developed associated autoimmune problems before puberty and were excluded from further study. The mean age of the onset of puberty among the remaining five patients was 12.3 +/- 0.4 yr, not different than the 11.4 +/- 0.4 yr reported for normal American boys. Integrated plasma levels of testosterone, androstenedione, 17-hydroxyprogesterone, progesterone, and dehydroepiandrosterone were also determined in three Addisonian patients who had no associated autoimmune disease before puberty and their study date. Results were compared with integrated plasma levels from three other groups: four agonadal males, four normal adult males, and three pubertal boys. Integrated plasma levels of these steroids confirm that in a male, testosterone is essentially testicular in origin, dehydroepiandrosterone is mainly adrenal in origin, and androstenedione and 17-hydroxyprogesterone are derived from both sources.

Addison Disease↗
PubMed1979

Oxandrolone therapy in patients with Turner syndrome.

Long-term, low-dosage androgen treatment of patients with Turner syndrome results in more rapid growth and significantly greater adult height than in control patients who receive only estrogen for pubertal development. Seventeen patients treated with oxandrolone for one year and ten treated for two years had significantly greater growth velocities during than before treatment. Mean adult height of 25 patients treated with oxandrolone, fluoxymesterone, or both was significantly taller than the height of adult patients with Turner syndrome treated with estrogen only. Excessive skeletal maturation was not generally observed.

Body Height↗