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Biomedical subjects

C A Morris

Publications and source records attributed to C A Morris.

At least 73 records · Page 4Linked to original sources
PubMed1994

Supravalvular aortic stenosis associated with a deletion disrupting the elastin gene.

Supravalvular aortic stenosis (SVAS) is an inherited vascular disease that can cause heart failure and death. SVAS can be inherited as an autosomal dominant trait or as part of a developmental disorder, Williams syndrome (WS). In recent studies we presented evidence suggesting that a translocation disrupting the elastin gene caused SVAS in one family while deletions involving the entire elastin locus caused WS. In this study, pulsed-field, PCR, and Southern analyses showed that a 100-kb deletion of the 3' end of the elastin gene cosegregated with the disease in another SVAS family. DNA sequence analysis localized the breakpoint between elastin exons 27 and 28, the same region disrupted by the SVAS-associated translocation. These data indicate that mutations in the elastin gene cause SVAS and suggest that elastin exons 28-36 may encode critical domains for vascular development.

Aortic Stenosis, Subvalvular↗
PubMed1994

Crossbreeding of Ayrshire, brown Swiss, and Sahiwal cattle for annual and lifetime milk yield in the lowland tropics of Kenya.

Records from 1577 cows born from 1973 to 1983 on a ranch in lowland Kenya were analyzed for age at first calving, lactation length, lactational milk yield, calving interval, annual milk yield, and, for cows born from 1973 to 1979, number of calvings, productive lifetime in the herd, and lifetime milk yield. Partial lifetime yield (< or = 4 lactations) was studied for all cows. Rotational crosses of Ayrshire and Sahiwal, the crosses between them (interbreds), and the crosses sired by Brown Swiss from the rotational crosses were compared. The Ayrshire-sired rotational crosses yielded 4.8% more milk during a 19-d longer lactation and with a calving interval that was 14 d longer than those sired by Sahiwal. Milk yield for completed lactations of interbred cows was 4.5% less, and milk yield of Brown Swiss crosses was 9.5% more, than the average of the rotational crosses. Lifetime milk yields were 48% greater for the rotational crosses sired by Ayrshire than for those sired by Sahiwal. Interbreds yielded 34% less than the average of the rotational crosses. Over partial lifetimes, the rotational crosses sired by Ayrshire yielded 45% more milk than those sired by Sahiwal; the interbreds and the crosses sired by Brown Swiss yielded 34% less and 62% more milk, respectively, than the mean of the rotational crosses.

Animals↗
PubMed1993

Williams syndrome: autosomal dominant inheritance.

Williams syndrome (WS) usually occurs sporadically. Few familial cases of Williams syndrome have been described, and those reports have often lacked photographic documentation. We describe 3 families, including a 3-year-old boy and his 34-year-old father, a 2-year-old girl and her 30-year-old mother, and a 3-year-old girl and her 31-year-old mother. None of these patients has supravalvular aortic stenosis or chromosome abnormalities. In all 3 families, the parent with Williams syndrome was diagnosed after the identification of the syndrome in the affected child.

Abnormalities, Multiple↗
PubMed1993

Supravalvular aortic stenosis cosegregates with a familial 6; 7 translocation which disrupts the elastin gene.

Supravalvular aortic stenosis (SVAS) is an autosomal dominant disorder characterized by abnormalities of development of the great vessels. SVAS is also commonly part of Williams syndrome. Linkage to the elastin gene on chromosome 7q11 has recently been reported in two kindreds with SVAS. Previous reports of patients with 7q11 deletions have noted great vessel abnormalities in some. We report on a family in which SVAS is cosegregating with a balanced reciprocal translocation, t(6:7) (p21.1;q11.23), providing further evidence that SVAS is the result of a mutation of elastin at 7q11.23 region. The propositus of the translocation family has some minor anomalies which occur in Williams syndrome, suggesting that elastin abnormalities may cause some of the abnormalities found in Williams syndrome.

Adult↗
PubMed1993

A human vascular disorder, supravalvular aortic stenosis, maps to chromosome 7.

The pathogenesis of vascular disease is unclear, but genetic factors play an important role. In this study we performed linkage analyses in two families with supravalvular aortic stenosis, an inherited vascular disorder that causes narrowing of major arteries and may lead to cardiac overload and failure. DNA markers on the long arm of chromosome 7 (D7S371, D7S395, D7S448, and ELN) were linked to supravalvular aortic stenosis in both families with a combined logarithm of likelihood for linkage (lod score) of 5.9 at the ELN locus. These findings indicate that a gene for supravalvular aortic stenosis is located in the same chromosomal subunit as elastin, which becomes a candidate for the disease gene.

Aortic Valve Stenosis↗
PubMed1993

The elastin gene is disrupted by a translocation associated with supravalvular aortic stenosis.

To identify genes involved in vascular disease, we investigated patients with supravalvular aortic stenosis (SVAS), an inherited vascular disorder that causes hemodynamically significant narrowing of large elastic arteries. Pulsed-field gel and Southern analyses showed that a translocation near the elastin gene cosegregated with SVAS in one family. DNA sequence analyses demonstrated that the translocation disrupted the elastin gene and localized the breakpoint to exon 28. Taken together with our previous study linking SVAS to the elastin gene in two additional families and existing knowledge of vascular biology, these data suggest that mutations in the elastin gene can cause SVAS.

Amino Acid Sequence↗
PubMed1993

Hemizygosity at the elastin locus in a developmental disorder, Williams syndrome.

Williams syndrome (WS) is a developmental disorder affecting connective tissue and the central nervous system. A common feature of WS, supravalvular aortic stenosis, is also a distinct autosomal dominant disorder caused by mutations in the elastin gene. In this study, we identified hemizygosity at the elastin locus using genetic analyses in four familial and five sporadic cases of WS. Fluorescent in situ hybridization and quantitative Southern analyses confirmed these findings, demonstrating inherited and de novo deletions of the elastin gene. These data indicate that deletions involving one elastin allele cause WS and implicate elastin hemizygosity in the pathogenesis of the disease.

Adult↗
PubMed1993

Assessment of DNA fingerprinting for determining genetic diversity in sheep populations.

Genomic DNA, prepared from 12 animals from four sheep flocks, was digested with either HaeIII or HinfI and probed with three DNA fingerprinting probes. Mean DNA fingerprint band sharing and band frequency calculated for each flock were used to estimate genetic diversity. Each of the DNA fingerprinting systems showed the same trend in diversity within the sampled flocks, and greater diversity between the flocks than within the flocks. DNA fingerprinting therefore provides a useful measure of genetic diversity in sheep.

Analysis of Variance↗
PubMed1993

Vitronectin-mediated inhibition of complement: evidence for different binding sites for C5b-7 and C9.

In the activated complement system, vitronectin (complement S-protein) occupies the metastable membrane binding site of the nascent precursor complex C5b-7, so that the newly formed SC5b-7 is unable to insert into cell membranes. Some evidence also indicates that vitronectin limits on-going membrane-associated pore formation by inhibiting C9 polymerization. It has been assumed that these two stages of terminal complement complex (TCC) inhibition take place through charge interactions between the heparin-binding region of vitronectin and homologous cysteine-rich sequences of the late complement proteins C6, C7, C8 and C9. We examined SC5b-7 formation and inhibition of C9 binding in the TCC using separate haemolytic assays. The mode of action of vitronectin in these assays was compared with two 15mer peptides which span residues 348-379 of the heparin-binding region, and a heparin-affinity polypeptide, protamine sulphate. The results showed that vitronectin acts predominantly through SC5b-7 production with a lesser effect on the inhibition of C9 lytic pore formation. In contrast, protamine sulphate did not prevent C5b-7 membrane attachment, but was a potent inhibitor of C9-mediated lysis. The peptides did not inhibit C5b-7 membrane insertion and only one affected C9 binding. These data suggest that the two stages of TCC inhibition involve separate binding sites on the vitronectin molecule. The site for association with nascent C5b-7 is unknown, whereas inhibition of C9 binding and pore formation takes place through the heparin-binding region.

Amino Acid Sequence↗
PubMed1992

Beare-Stevenson cutis gyrata syndrome.

Beare-Stevenson cutis gyrata syndrome consists of skin furrows of corrugated appearance, acanthosis nigricans, craniofacial anomalies, particularly craniosynostosis and ear defects, anogenital anomalies, skin tags, and prominent umbilical stump. Four cases of this striking syndrome are reported. Together with two previously reported cases, the syndrome is delineated from the six known cases. Cutis gyrata variably affects the scalp, forehead, face, preauricular area, neck, trunk, hands, and feet. Craniosynostosis is present in four cases, with cloverleaf skull in three of these. Intrauterine growth has been normal in all cases. Performance and life expectation appear to be related to the presence or absence of cloverleaf skull. All cases observed to date have been sporadic. Increased paternal age suggests the possibility of an autosomal dominant mutation.

Abnormalities, Multiple↗
PubMed1992

The value of complement measurements in the assessment of lupus activity.

The complement system was studied prospectively in 29 patients, predominantly renal (25), with systemic lupus erythematosus (SLE) to examine the value of complement assays in the distinction between active and inactive disease. Disease activity was evaluated primarily by clinical, biochemical and histological parameters which were obtained at the time of assessment. Fourteen patients had active disease, as assessed by clinical and laboratory criteria. C1q, C4, C4a, C2, C3, C3a, C5, total haemolytic activity (CH50) and complement inhibitors were measured in each patient. The ratios of C4a:C4 and C3a:C3 were also calculated. Values for all components except C5 were different between control subjects and active patients while only CH50 was different between inactive patients and controls. All parameters except C4a:C4 and C5 were different between active and inactive patients. There was a highly significant difference in the number of active patients with reduced levels of C2, C3 and C3a:C3 compared to inactive patients (i.e. p less than 0.001) whereas lesser or no difference was observed for other parameters. The concentration of complement inhibitors was elevated in both groups. We conclude that, among readily available complement parameters, C2 and C3 provide the best assessment of disease activity in patients with SLE.

Adult↗
PubMed1992

18p- syndrome and hypopituitarism.

A patient is described with 18p- syndrome and hypopituitarism. This is the first patient with this syndrome who has been shown to benefit from growth hormone therapy. Patients with this syndrome who have growth deficiency should be considered for evaluation for hypopituitarism, if the quality of their lives would improve with an increase in stature.

Abnormalities, Multiple↗
PubMed1991

Race and liver transplantation.

Little is known about the effect of race on the outcome of liver transplantation. We retrospectively reviewed a series of 358 recipients of orthotopic liver transplants to address this issue. Black recipients were underrepresented compared with the general population (6% of transplant recipients vs 12% of the population). Black recipients appeared sicker when presenting for transplantation, as evidenced by a higher priority score and a significantly greater incidence of acute and fulminant presentation. Despite this, black recipients had survival rates following transplantation that were not significantly different from those of white recipients; the 1-, 2-, and 3-year actuarial survival rates of blacks were 89.6%, 68.3%, and 68.3%, respectively, while the actuarial survival rates of whites at the same periods were 86%, 82.4%, and 78.6%, respectively. We conclude that blacks can have an outcome equal to whites following liver transplantation but they are underrepresented compared with the general population.

Adolescent↗
PubMed1991

Long-term survival and renal function following liver transplantation in patients with and without hepatorenal syndrome--experience in 300 patients.

We have retrospectively reviewed the first 308 patients undergoing orthotopic liver transplantation (OLTX) at our institution to determine the following: 1) To what extent does renal function deteriorate postoperatively? 2) To what extent does renal function recover after OLTX for hepatorenal syndrome (HRS)? 3) What is the survival rate of patients with HRS compared with those without HRS? In non-HRS patients, GFR declined from 97.1 +/- 2.9 cc/min to 56.6 +/- 2.4 cc/min at 6 weeks postoperative, 62.6 +/- 2.6 cc/min at 1 year, and 58.3 +/- 3.5 cc/min at 2 years. In HRS patients, GFR increased from 19.9 +/- 3.6 cc/min to 32.5 +/- 3.1 cc/min at 6 weeks, 45.9 +/- 5.5 cc/min at 1 year, and 37.9 +/- 5.9 cc/min at 2 years. Dosages of cyclosporine were comparable in both groups. There was no difference in perioperative (90-day) mortality. One- and 2-year actuarial survival rates in the non-HRS patients were 87.2% and 82.1%, respectively. The actuarial 1- and 2-year survival rate for the HRS patients was 76.6% (P = NS). Ten percent of HRS patients developed ESRD posttransplant compared with 0.8% of non-HRS patients (P less than 0.005). We conclude that patients with HRS can safely undergo OLTX with acceptable perioperative mortality and good long-term survival. Most HRS patients have return of acceptable renal function. Patients without HRS have a severe decline in GFR posttransplant, which is stable up to 3 years posttransplant.

Creatinine↗