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J Amos

Publications and source records attributed to J Amos.

25 records · Page 2Linked to original sources
PubMed1971

Further observations on the effect of synthetic thyrotropin-releasing hormone in man.

Synthetic thyrotrophin-releasing hormone (TRH) given intravenously in doses of 50 mug or more causes a significant rise in serum thyroid-stimulating hormone (TSH) levels but has no effect on serum growth hormone, plasma luteinizing hormone, or plasma 11-hydroxycorticosteroids under carefully controlled basal conditions.The peak TSH response to intravenous TRH occurs at 20 minutes. The mild and transient side effects, which occur only after intravenous TRH, include nausea, a flushing sensation, a desire to micturate, a peculiar taste, and tightness in the chest. There is considerable variability in response to a given dose of TRH in the same subject on different occasions and in different subjects. Oral administration of TRH in doses of 1 mg and above causes a rise in serum TSH, maximal at two hours, a consistent response being obtained at doses of 20 mg and above. A rise in serum protein-bound iodine (P.B.I.) follows that of TSH, a consistent response being observed at 40-mg doses of TRH orally. Measurements of serum TSH after intravenous administration of TRH or of serum TSH or serum P.B.I. after oral TRH should prove useful tests of pituitary TSH reserve.

Administration, Oral↗
PubMed1971

Radioimmunoassay of human serum thyrotrophin.

The double antibody radioimmunoassay of serum thyroid-stimulating hormone (TSH) allows measurement of circulating levels of the hormone in most normal subjects. The serum TSH level in normal subjects is 1.6 +/- 0.8muU/ml. Patients with non-toxic goitre and acromegaly have normal TSH levels. Values are always raised in hypothyroid patients (with primary thyroid disease) and are significantly lowered in those with hyperthyroidism. Of the many stimuli used in an attempt to raise TSH levels in normal adult subjects only three-synthetic thyrotrophin-releasing hormone, ethinyloestradiol, and carbimazole plus iodides-have been effective. The major clinical application of the TSH immunoassay lies in the diagnosis of minor degrees of hypothyroidism. An impaired response of serum TSH to synthetic thyrotrophin-releasing hormone should also help in the diagnosis of hypopituitarism affecting TSH production.

Acromegaly↗
PubMed1970

Thyroid-stimulating hormone response to synthetic thyrotrophin releasing hormone in man.

Synthetic thyrotrophin-releasing hormone, L-pyroglutamyl-L-histidyl-L-proline-amide, has been administered intravenously to euthyroid subjects in doses ranging from 1 to 200 mug. Its effect was assessed by serial measurements of serum thyroid-stimulating hormone (T.S.H.). A rise in serum T.S.H. was detectable five minutes after administration of 50 mug. of thyrotrophin-releasing hormone, reaching a maximum in 15 to 30 minutes, and then gradually declining over the next 120 minutes. Doses of 100 and 200 mug. of thyrotrophin-releasing hormone produced even greater rises of T.S.H. in some cases. The only side-effect noted was transient nausea with doses greater than 50 mug. Measurement of serum T.S.H. levels after administration of thyrotrophin-releasing hormone should prove a useful test of pituitary T.S.H. release and may help to distinguish pituitary and hypothalamic lesions.

Adult↗
PubMedDate not supplied

Analysis of deletions in DNA from patients with Becker and Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder for which the biochemical defect is as yet unknown. Recently, two cloned segments of human X-chromosome DNA have been described which detect structural alterations within or near the genetic locus responsible for the disorder. Both of these cloned segments were described as tightly linked to the locus and were capable of detecting deletions in the DNA of boys affected with DMD. In an attempt to determine more precisely the occurrence of these deletions within a large population of DMD patients and the accuracy of one of the segments, DXS164 (pERT87), in determining the inheritance of the DMD X chromosome, the subclones 1, 8 and 15 were made available to many investigators throughout the world. Here we describe the combined results of more than 20 research laboratories with respect to the occurrence of deletions at the DXS164 locus in DNA samples isolated from patients with DMD and Becker muscular dystrophy (BMD). The results indicate that the DXS164 locus apparently recombines with DMD 5% of the time, but is probably located between independent sites of mutation which yield DMD. The breakpoints of some deletions are delineated within the DXS164 locus, and it is evident that the deletions at the DMD locus are frequent and extremely large.

Chromosome Deletion↗
PubMedDate not supplied

Genotype-phenotype correlation and frequency of the 3199del6 cystic fibrosis mutation among I148T carriers: results from a collaborative study.

PURPOSE: We expect that the mutation panel currently recommended for preconception/prenatal CF carrier screening will be modified as new information is learned regarding the phenotype associated with specific mutations and allele frequencies in various populations. One such example is the I148T mutation, originally described as a severe CF mutation. After implementation of CF population-based carrier screening, we learned that I148T exists as a complex allele with 3199del6 in patients with clinical CF, whereas asymptomatic compound heterozygotes for I148T and a second severe CF mutation were negative for 3199del6. METHODS: We performed reflex testing for 3199del6 on 663 unrelated specimens, including I148T heterozygotes, compound heterozygotes, and a homozygous individual. RESULTS: Less than 1% of I148T carriers were also positive for 3199del6. Excluding subjects tested because of a suspected or known CF diagnosis or positive family history, 0.6% of I148T-positive individuals were also positive for 3199del6. We identified 1 I148T homozygote and 6 unrelated compound heterozygous individuals with I148T and a second CF variant (2 of whom also carried 3199del6). In addition, one fetus with echogenic bowel and one infertile male were heterozygous for I148T (3199del6 negative). CONCLUSIONS: Reflex testing for 3199del6 should be considered whenever I148T is identified. Reflex testing is of particular importance for any symptomatic patient or whenever one member of a couple carries a deleterious CF mutation and the other member is an I148T heterozygote. Further population data are required to determine if I148T, in the absence of 3199del6, is associated with mild or atypical CF or male infertility.

Cystic Fibrosis↗