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Biomedical subjects

J L Watt

Publications and source records attributed to J L Watt.

At least 19 recordsLinked to original sources
PubMed1992

Is an abbreviated bronchial challenge with histamine valid?

Investigators have validated an abbreviated protocol for testing nonspecific bronchial reactivity with methacholine. We performed a similar validation study with histamine, another bronchoprovocative agent known to induce airflow obstruction. Histamine is pharmacologically distinct from methacholine and, under some circumstances, may provide specific clinical and investigative advantages to methacholine. Twenty-four patients with a clinical history of asthma underwent bronchoprovocative testing using the standard histamine airway protocol recommended by the American Academy of Allergy, Committee on Standardization of Bronchoprovocation. In addition, two abbreviated histamine challenge protocols were tested using the same administration and testing equipment. The abbreviated protocols involved fewer dilutions and dosages of histamine than the standard histamine protocol but covered the same range of cumulative doses. The two abbreviated protocols differed only in the intervals for determination of FEV1 between doses of histamine (30 s vs 3 min). The sequence of these three protocols was randomized for each study subject and each airway challenge was separated by one week. The two abbreviated protocols took significantly less time to administer than the standard protocol--18 min vs 30 min vs 44 min. Both the provocative dose to cause a 20 percent decline in the FEV1 (PD20 FEV1) and the slope of the dose-response curve were not significantly different between the standard protocol and either of the two abbreviated protocols. Moreover, a high degree of agreement was observed between the two abbreviated protocols and the standard histamine protocol for both the PD20 FEV1 and the slope of the dose-response curve. These findings indicate that similar estimates of bronchial reactivity are obtained from either of the abbreviated protocols when compared with the standard histamine protocol.

Adult↗
PubMed1990

Terminal deletion (14)(q32.3): a new case.

A mildly dysmorphic, 2 year old girl with mental retardation was found to have a small de novo terminal deletion of the long arm of chromosome 14, del(14)(q32.3). She was found to have features in common with two previous terminal deletion cases and particularly with the well documented ring 14 syndrome, although seizures, a characteristic feature of ring 14, were notably absent.

Child, Preschool↗
PubMed1989

An unusual case of mosaic Down's syndrome involving two different Robertsonian translocations.

A baby girl with some of the stigmata of Down's syndrome was found to be a mosaic with three different cell lines: 45,XX,-13,-21,+t(13q21q)/(46,XX/46,XX, -21,+t(21q21q). The chromosome rearrangements detected in this patient appear to have arisen de novo. In the normal cell line the terminal end of the p arm of one chromosome 21 is thought to have been damaged. It seems probable that this is related to the other chromosomal anomalies found.

Chromosome Banding↗
PubMed1988

Are double translocations double trouble?

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child. This is not based on theoretical considerations of segregation patterns, but extrapolated from what is known empirically about the viable segregation patterns in carriers of single reciprocal translocations. It assumes that there is no interference with the independent assortment of the two separate exchanges, unless a common participating chromosome is involved. The possibility of an interchromosomal effect has not been taken into consideration.

Congenital Abnormalities↗
PubMed1987

Trisomy 1 in an eight cell human pre-embryo.

The high incidence of chromosome abnormalities in clinically recognised pregnancies is well documented, but experience of these problems at the time of conception is extremely limited. Using donated oocytes from women seeking surgical sterilisation, we have established reliable cytogenetic techniques for chromosome analysis of human pre-embryos. These have resulted in the first report of trisomy 1. The pre-embryo showed no other obvious abnormality in relation to follicular characteristics, embryo morphology, and cleavage kinetics. The usefulness of such data in explaining the high incidence of occult human pregnancy loss and the current poor success following embryo replacement is emphasised.

Chromosome Banding↗
PubMed1987

Structural rearrangements in the parents of children with primary trisomy 21.

A retrospective cytogenetic study was carried out on the parents of children with regular trisomy 21 Down's syndrome. In a total of 128 parents referred routinely to our laboratory after the birth of their affected child, three structural abnormalities, a reciprocal translocation and two pericentric inversions not involving chromosome 21, were detected. This is about 10 times the frequency expected based on current figures from consecutive newborn studies. In addition, the brother of one of nine older people with trisomy 21 referred for cytogenetic analysis for the first time was found to have a reciprocal translocation. This supports the contention made by others that an interchromosomal effect does exist in man. It is suggested that centres who routinely analyse the parents of their trisomy 21 referrals in an unbiased fashion should review their records. They will almost certainly contain useful information regarding the possible existence of this phenomenon and may even contain clues as to its nature. In addition to its undoubted scientific value, such data should prove useful in the genetic counselling of carriers of structural rearrangements.

Chromosome Aberrations↗
PubMed1986

Variation of SCE frequency in lymphocyte cultures from patients with Hodgkin's disease before, during, and after treatment.

Seven patients with newly-diagnosed Hodgkin's disease, having standard mustine-vinblastine-prednisolone-procarbazine therapy, had a large and regular pattern of rise in SCE frequency in their peripheral lymphocytes, which apparently started to fall before the end of the course (32 wk). In contrast, SCE frequency fell below normal in the lymphocytes of nine patients having mantle radiotherapy. Twenty-eight patients studied 2-13 yr after initial chemotherapy or radiotherapy for Hodgkin's disease had normal or near normal SCE frequencies.

Adult↗
PubMed1986

Cytogenetic analysis in 100 spontaneous abortions in North-East Scotland.

The results of an extremely detailed cytogenetic analysis on 100 spontaneous abortions occurring in the Aberdeen area over a 3 year period is presented. A comparison with other published series reveals that there is a higher culture success rate (93%) accompanied by a lower incidence of trisomy and a higher incidence of triploidy, although the percentage of chromosomally abnormal foetuses in first trimester abortions is comparable with other studies. However, these apparent discrepancies can largely be explained on the basis of gestational age and sampling variation.

Abortion, Spontaneous↗
PubMed1986

Chorion in culture.

This study is based on the processing of 115 samples of pure chorion. The different types of colony morphology, together with cytogenetic analysis, indicate the predisposition of chorion cells to artefacts of culture. Chorion survives longer than other foetal tissues and can be cultured when those are dead or contaminated (e.g. in macerated foetuses and missed abortions) making it a suitable and popular tissue for cytogenetic purposes. However, our results indicate that it is slow in culture and prone to chromosome variation so that pseudomosaicism frequently arises and may lead to misdiagnosis. We therefore suggest that cytogenetic analysis of spontaneous abortion material is interpreted with caution in cases where chorion is the only tissue cultured, especially when mosaicism is found.

Cell Division↗
PubMed1986

A paracentric inversion of 7q illustrating a possible interchromosomal effect.

A family is described in which the proband has a rearranged X chromosome involving monosomy Xp and trisomy Xq, while the mother has a paracentric inversion of chromosome 7. It is suggested that the phenomenon of interchromosomal effect may link these observations. A brief review of the published and computer catalogued data on paracentric inversion in man is included.

Chromosome Inversion↗
PubMed1986

Partial trisomy 7 (q32----qter) syndrome in two children.

Two unrelated children are described with a partial trisomy 7 (q32----qter). Their phenotypes are compared with other reported cases with both this trisomy and others of the 7q arm. Several apparently useful pathognomonic features are distinguished. The phenotypic variability between trisomic persons within and between families is discussed. It is suggested that the disparate monosomies always associated with these trisomies may not make a major contribution to this variability. The importance for genetic counselling of reporting in detail the clinical appearance and development of all children with this rate trisomy is emphasised.

Abnormalities, Multiple↗
PubMed1985

Chromosome damage and sister chromatid exchanges in lymphocyte cultures from patients with two primary cancers.

Sister chromatid exchanges (SCEs) and chromosome damage were scored in lymphocyte cultures from 11 patients with two or more primary cancers and were compared with normal controls. None of the patients had a constitutional chromosome anomaly, but six showed evidence of chromosome instability, which could not be accounted for by treatment, expressed either as elevated SCE frequency or increased nonspecific chromosome damage and chromosome loss. Chromosome damage included major rearrangements as well as deletions and gaps. The possibility of common mechanisms in chromosome instability leading to susceptibility to a heterogeneous group of primary cancers is discussed.

Aged↗
PubMed1984

Triploidy, partial mole and dispermy. An investigation of 12 cases.

Twelve triploid abortuses were investigated to determine the origin of the additional haploid set and were retrospectively examined for the development of partial hydatidiform mole. Eight out of ten suitable triploids were diagnosed as partial mole. Dispermy was indicated as the cause of triploidy in 6 informative cases of which 3 were also partial moles. However, one diandric triploid had no features of partial mole. The problem of maternal cell contamination in triploids and the difficulty of diagnosing partial moles on pathological grounds alone are discussed.

Abortion, Spontaneous↗
PubMed1984

A familial insertion involving an active nucleolar organiser within chromosome 12.

As far as the authors are aware this is the first report of the insertion of an active NOR into a non-acrocentric chromosome, although a simple translocation involving an active NOR has been previously recorded. More specifically, this case involves the non-reciprocal translocation of the centromere and stalk of an acrocentric into 12p, generating an apparently stable dicentric chromosome. The insertion is seen in three generations and may be relatively genetically benign. The abnormality is fully described by G and sequential C banding, DA/DAPI fluorescence, kinetochore staining, and Ag-NOR staining, and the findings are discussed in the light of the limited published reports of insertion in man.

Chromosomes, Human, 6-12 and X↗