PubMed Health⌕ Search

Biomedical subjects

J Hewitt

Publications and source records attributed to J Hewitt.

At least 19 recordsLinked to original sources
PubMed1992

Successful treatment of failed AID cases by use of gamete intra-fallopian transfer using donor semen (GIFT (D)).

Over a 13-month period in a newly opened assisted conception unit at the Women's Hospital, Liverpool, gamete intra-fallopian transfer using donor semen, GIFT (D) was offered to eighteen couples who had failed to conceive after numerous cycles of treatment with artificial insemination by donor semen (AID). The indication for the use of donor semen was either azo- or severe oligoaesthenospermia, and, in addition, the female partners have been exhaustively investigated with no major cause found to account for the couple's infertility. Using a basic clomiphene citrate and human menopausal gonadotrophin protocol it was possible to achieve a pregnancy rate of 56% per GIFT (D) cycle. As a consequence of these results it is now our policy to treat couples whose infertility is due to an unresolvable male factor with AID for 12 cycles only. If they have been unsuccessful in achieving a pregnancy after this time, they are offered GIFT (D).

Adult↗
PubMed1992

Toxic epidermal necrolysis treated with cyclosporin.

Toxic epidermal necrolysis (TEN) is a severe life-threatening disorder which has many features in common with graft-versus-host disease. However, immunosuppression with steroids gives disappointing results and is possibly detrimental. We treated two patients who had TEN with a combination of cyclosporin and steroids which resulted in an apparent halt to the evolution of the disease, and a further relapse was aborted using cyclosporin in one of these patients. We feel that the use of this drug in the early treatment of TEN where it is used as a specific therapy aimed at the primary immunopathological events and is used in conjunction with the supportive care patients require, needs to be further evaluated.

Adult↗
PubMed1991

The intra-vaginal culture technique for supernumerary oocytes from gamete intra-Fallopian transfer.

The intra-vaginal culture technique has been utilized for supernumerary oocytes produced as a result of gamete intra-Fallopian transfer therapy. This has enabled knowledge regarding fertilization to be gained and in addition, by adapting the technique to include a transportational element, it has been possible to perform embryo cryopreservation in a separate unit. Analysis of the results of 72 GIFT treatment cycles reveals that when more than four oocytes were collected at laparoscopy, 15/32 (47%) pregnancies were achieved, in comparison with 7/40 pregnancies (17.5%) when four or fewer oocytes were recovered (P less than 0.01). Whilst the GIFT pregnancy rate was higher when spare oocytes were fertilized and embryos cryopreserved (9/16; 56%), six of the 16 patients (37.5%) with failed fertilization of spare oocytes still achieved a GIFT pregnancy.

Adult↗
PubMed1990

Intravaginal culture: present and potential uses.

Over recent years, a simplified method of in-vitro fertilization (IVF), known as intravaginal culture (IVC), has been developed. This article will outline the background to its introduction, provide technical details regarding its practice, review the results achieved to date and explore some of the areas in which this innovation may prove useful in the future.

Female↗
PubMed1988

A highly polymorphic locus very tightly linked to the Huntington's disease gene.

The genetic defect in Huntington's disease (HD), an inherited neuropsychiatric disorder of unknown etiology, has not been defined. The discovery of linkage between HD and the DNA marker D4S10(G8) raised the possibility of isolating the disease gene on the basis of its chromosomal location, in addition to providing a limited presymptomatic test for the late onset disorder. But it has been difficult to isolate other DNA markers nearer to the HD gene, and this has hampered attempts to identify the disease locus and limited the applicability and accuracy of predictive testing. Recently, several new DNA markers from the region of the genome near the HD gene have been isolated using a directed cloning strategy. We describe here the characterization of one of these new markers, D4S95, a highly polymorphic locus which displays no recombination with the HD gene in the families tested. The high degree of polymorphism at this locus and its proximity to the HD gene make it extremely useful for predictive testing and as a new starting point for attempts to clone the disease gene.

Alleles↗
PubMed1988

Presymptomatic neuropsychological impairment in Huntington's disease.

Ten asymptomatic individuals at risk for Huntington's disease (HD) were determined by the use of linked DNA probes to have a high (HD+ group) or low (HD- group) probability of having inherited the mutant gene. Neuropsychological examination, performed without knowledge of DNA results, revealed impairments in five of seven subjects in the HD+ group. Abnormalities were related to visuospatial abilities or to functions associated with the frontal lobes. All three subjects in the HD- group showed no neuropsychological impairment. Statistical analyses confirmed differences between the HD+ and HD- groups. Affected parents of subjects were at least 12 years older at symptom onset. These results demonstrate that clear neuropsychological impairment may be present in HD even when overt signs and symptoms are not expected for a number of years.

Adult↗
PubMed1988

A polymorphic DNA marker that represents a conserved expressed sequence in the region of the Huntington disease gene.

A polymorphic marker (D4S62) that is genetically closely linked to D4S10 and is in the region of the gene for Huntington disease is described. A four-allele polymorphism is detected when HincII-digested DNA is hybridized with D4S62. D4S62 maps, by Southern blot analysis using somatic-cell hybrids, to 4p16.1 closer to the centromere than does D4S10. The use of the polymorphisms detected by D4S62 increases the informativeness of markers close to the gene for Huntington disease and will be useful for preclinical diagnosis. D4S62 detects transcripts of approximately 6,000 nucleotides in rat, mouse, and monkey liver and brain. This represents the first demonstration of conserved expressed sequences close to the gene for Huntington disease.

Alleles↗
PubMed1987

First-trimester prenatal diagnosis for Huntington's disease with DNA probes.

Polymorphic DNA probes linked to the locus for Huntington disease (HD) were used for prenatal diagnosis of a 10-week fetus at 25% risk for the disease. The fetus proved to have a 48% risk of having inherited the HD mutation which was similar to that for the at-risk parent (50%). On this basis the parents elected to terminate the pregnancy. When appropriate family members are available and DNA studies are informative, prenatal diagnosis of HD with polymorphic DNA probes can determine the at-risk status of the fetus with 96% accuracy.

Adult↗
PubMed1987

Intravenous energy and amino acids in the preterm newborn infant: effects on metabolic rate and potential mechanisms of action.

The effects of intravenously administered amino acids and of varying amounts of energy on metabolic rate were studied and potential mechanisms examined in 19 healthy 4- to 6-day-old preterm (30 to 32 weeks gestation) infants. The infants were randomized to three groups. Group 1 (n = 6) received nonprotein energy 38 kcal/kg/d; group 2 (n = 5), 64 kcal/kg/d; and group 3 (n = 8), 64 kcal/kg/d plus 1 to 2 g/kg/d crystalline amino acids. Thirty-six hours after beginning the infusion, oxygen consumption (VO2) was measured by indirect calorimetry for 5 to 6 hours. Simultaneously, urine was collected for urinary norepinephrine excretion, which was determined using liquid chromatography with electrochemical detection. Serum thyroxine (T4) and triiodothyronine (T3) concentrations were determined by radioimmunoassay. Group 1 had lower VO2 and urinary norepinephrine excretion than did groups 2 and 3, which did not differ. T4 and T3 were not different among the three groups. The demonstrated simultaneous changes in VO2 and norepinephrine excretion with varying energy intakes independent of age supports energy intake as a modulator of the sympathetic nervous system, which in turn controls metabolic rate. Moderate amounts of intravenously administered amino acids do not appear to play an active role in this process; nor do they alter T3 and T4 valves. When VO2 increased with increasing energy intake, T3 and T4 were unaffected, supporting a passive role for thyroid hormones in diet-induced thermogenesis.

Amino Acids↗
PubMed1987

The combined use of positron emission tomography and DNA polymorphisms for preclinical detection of Huntington's disease.

Twenty-three persons at risk for Huntington's disease (HD) have been studied using a polymorphic human linked DNA marker (D4S10) and positron emission tomography (PET). We determined the likelihood of inheritance of the gene for HD in 13 persons, using DNA polymorphism studies. Of these, eight persons had a greater than 90% probability of being presymptomatic heterozygotes for HD. Three of these eight subjects had caudate glucose utilization detected by PET that was more than 2 standard deviations (SD) below the age-matched control mean. Measurement of caudate glucose utilization in the other five presumed presymptomatic heterozygotes revealed results between 1 and 2 SD below the mean. Five persons had a less than 10% likelihood of having inherited the abnormal gene for HD. Of these, four had normal rates of glucose utilization in the caudate nuclei. However, one individual with DNA results indicating a low risk of developing HD had abnormally low measures of caudate glucose utilization. This suggests that a recombination had occurred between the linked marker and the gene in this person. These studies suggest that PET studies of caudate glucose utilization may help to confirm results of DNA studies in some persons, and may provide an opportunity to detect when DNA results may be incorrect due to recombination.

Brain↗
PubMed1987

DNA polymorphisms in and around the Apo-A1-CIII genes and genetic hyperlipidemias.

We have studied the frequency of DNA polymorphisms in and around the apolipoprotein A-1 (Apo-A1) and apolipoprotein CIII (Apo-CIII) gene loci in 53 persons of Caucasian descent with genetic hyperlipidemias. Three restriction-fragment-length polymorphisms (RFLPs) have previously been located 5' and 3' to the Apo-A1 gene and in the Apo-CIII gene and were detected after digestion with XmnI, PstI, and SstI, respectively, and hybridization with a 2.2-kb fragment of the Apo-A1 gene. These RFLPs are in linkage equilibrium. The rare variant sites for XmnI (X2) and SstI (S2) were more frequent in familial combined hyperlipidemia (FCH) than in controls and persons with other genetic hyperlipidemias. When considered as a haplotype, this difference was significant (P less than .03). The findings in this study suggest that the previously reported association between S2 and hypertriglyceridemia may be accounted for, in part, by inclusion of numerous patients with FCH. Our data provide further evidence that these RFLPs around and within the Apo-A1/Apo-CIII genes do not participate in unmasking clinical expression in persons with familial dysbetalipoproteinemia.

Adult↗