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Biomedical subjects

K Morgan

Publications and source records attributed to K Morgan.

At least 307 records · Page 17Linked to original sources

Mandibulofacial dysostosis in Hutterite sibs: a possible recessive trait.

We report on two sisters with mandibulofacial dysostosis (MFD). Both parents were examined carefully by clinical, radiographic, audiologic, and cephalometric methods. Neither showed evidence of the MFD gene. Photographs of three grandparents and examination of one disclosed no evidence of MFD. The parents are from the Hutterite Brethren and are consanguineous. Examination of the literature on MFD disclosed a number of other families with affected sibs and apparently normal parents. These families raise the possibility of an autosomal recessive form of MFD or some other explanation such as germinal mosaicism, chromosome rearrangement, or delayed mutation. For our family, the recurrence risk is probably 25%, but since germinal mosaicism cannot be excluded, it could be as high as 50%.

Consanguinity↗

Screening for methylmalonic aciduria in Alberta: a voluntary program with particular significance for the Hutterite Brethren.

A selective, voluntary urine screening program has been established to facilitate detection and early treatment of infants with methylmalonic acidurias (MMA), a group of rare, potentially lethal, autosomal recessive disorders of organic acid metabolism. The laboratory methods have been modified for newborn infants so that urine specimens can be collected on filter paper in the diaper and tested by the thin-layer chromatography method. One Hutterite child was previously known to have methylmalonyl-coenzyme A (MMCoA) mutase deficiency (mut0) which is unresponsive to vitamin B12 but is responsive to diet and other therapeutic measures. No undiagnosed existing cases of MMA were identified by the voluntary screening program among 1,165 Hutterite infants and preschool children.

Alberta↗

Hutterite cerebro-osteo-nephrodysplasia: autosomal recessive trait in a Lehrerleut Hutterite family from Montana.

We are reporting on two Lehrerleut Hutterite sisters who have a syndrome of congenital shortness with mild spondylorhizomelic dwarfism; later failure to thrive, ie deceleration of weight gain presumably due to CNS-based severe feeding problems; a CNS defect, probably developmental (not biochemical) with normal prenatal brain growth but later deceleration from 50th to 2nd centile associated with severe mental retardation and decorticate disturbances of neurologic function; and possible renal involvement with terminal nephrotic syndrome. This seems to be a previously undescribed pleiotropic autosomal recessive trait.

Abnormalities, Multiple↗

Congenital contractures, edema, hyperkeratosis, and intrauterine growth retardation: a fatal syndrome in Hutterite and Mennonite kindreds.

We present clinical findings in infants from three kindreds (two Hutterite and one Mennonite) with an apparently unique, fatal disorder. The major manifestations consist of severe intrauterine growth retardation, congenital contractures, and tense skin which is easily eroded. The skin is tightly drawn over the face, giving an abnormal appearance consisting of a narrow, pinched nose, small mouth, limited jaw mobility, and ectropion (in one). One infant had first-degree hypospadias. Apart from this, there were no organ malformations and the infants did not have hydrops. Histologically, the skin showed hyperkeratosis. It is postulated that this is a tissue dysplasia and that all of the clinical effects are secondary. The disorder appears to be an autosomal recessive trait. The two Hutterite families are from different endogamous subdivisions. They are related as fourth cousins once-removed and fifth cousins in multiple ways through the six nearest common ancestors of all four parents. There are 25 founders (11 couples and three individuals) who are common ancestors. We computed the probability of joint descent of the four alleles in each pair of parents and in a sample of Alberta Hutterite couples, assuming that each of the common founders in turn was the original carrier. For an allele from one particular founder couple, there is a relatively greater probability of identity by descent for each pair of parents than on the average for other couples of the same endogamous subdivision.

Abnormalities, Multiple↗

Congenital anomalies in the Hutterite population: a preliminary survey and hypothesis.

The Alberta Provincial Congenital Anomaly (CA) Surveillance reporting forms were scanned for infants whose surnames and addresses identified them as belonging to the Hutterite Brethren. Death registrations (of infants up to 1 year) and stillbirth registrations were similarly scanned. While the overall percentage of total malformations (5%) and major malformations (2%) was no different from that of the total population of Alberta, closer examination of the actual entities showed a large number of monogenic disorders among the Hutterites. The frequency of multifactorial congenital anomalies was approximately 1%. The inbreeding coefficients, using a genealogic data base, were computed for each "case baby" and two Hutterite "control babies," the latter being births preceding and succeeding the case baby. There was no statistical difference in the distribution of inbreeding coefficients between the case and control groups. While the data are based on small numbers and therefore are preliminary, they suggest that the Hutterite lifestyle, of good nutrition (using largely home prepared foods), absence of tobacco and minimal alcohol consumption, may be one factor responsible for fewer multifactorial CAs whose occurrence is environmentally susceptible to such influences. Studies of populations with a low incidence of disorders are just as important as those with a high incidence.

Alberta↗

The natural history of familial hypopituitarism.

Familial hypopituitarism in the Hutterite Brethren is an autosomal recessive disorder involving sequential loss of anterior pituitary tropic hormones. Five individuals from two closely related families have been followed for 19 years. Both families are well integrated into the Hutterite community. Three sibs elected not to be treated with growth hormone and sex steroids. These sibs developed growth hormone and gonadotropin deficiency in the first decade of life, with subsequent loss of TSH function and finally ACTH deficiency in the third decade. The pattern of hormone loss differed in the second family, in that deficiency of growth hormone, gonadotropins, and TSH was evident in the first decade. A third family has been reported to have the same disorder and is from a different endogamous subdivision from that of the two families described here. Genealogical analysis of the three families shows that there are four ancestral couples common to the six parents. Thus all affected individuals are likely to be identical by descent for the same ancestral allele. The gene for hypopituitarism is not closely linked to the gene for growth hormone nor to the HLA region.

Chromosomes, Human, 16-18↗

Effects of repeated dose nitrazepam and lormetazepam on psychomotor performance in the elderly.

The daytime psychomotor performance of 12 healthy subjects of mean age 81.4 years was examined in a double-blind crossover study following single and repeated nightly doses of nitrazepam 5 mg, lormetazepam 1 mg, and placebo. Accuracy of performance on the Gibson spiral maze was unaffected by both drugs. On a reciprocal tapping task, speed was similarly unaffected. However, while neither drug significantly impaired accuracy on reciprocal tapping after the first dose, nitrazepam, but not lormetazepam, significantly reduced overall accuracy after seven consecutive doses, an effect consistent with drug accumulation.

Aged↗

Ovarian strumal carcinoid tumor with amyloid stroma--report of a case with 20-year follow-up.

We report a case of strumal carcinoid tumor arising in the left ovary of a 20-year-old woman. Histologically, microfollicular, solid, and trabecular areas were present, and amyloid stroma was demonstrated. Many cells contained argyrophilic granules, and thyroglobulin and calcitonin were demonstrated immunohistochemically in several areas. Ultrastructurally the cells resembled thyroid follicular cells and contained neurosecretory granules. It is concluded that strumal carcinoid is of endodermal origin, and shows evidence of thyroid and C-cell differentiation.

APUD Cells↗

Leukaemic promyelocytes and normal bone marrow cells release a passive sodium transport modifier (inhibitin).

Previous studies have shown that leukaemic immature cells, specifically promyelocytes but not mature leucocytes, contain and release an inhibitor of ouabain-insensitive sodium transport (inhibitin). In the present study, medium from cultured leukaemic promyelocytes significantly reduced the ouabain-insensitive sodium efflux from erythrocytes, whereas medium from the same cell line which had been made to differentiate did not have this effect. Culture medium from normal bone marrow cells (containing promyelocytes) also significantly (P less than 0.001) reduced ouabain-insensitive sodium efflux. These data suggest that inhibitin is secreted by primitive but not by mature leukaemic cells and normal bone marrow cells.

Biological Transport↗

Heparin-induced thrombocytopenia and thrombosis: detection and specificity of a platelet-aggregating IgG.

A 46-year-old female who died as a result of thrombocytopenia associated with multiple arterial occlusions and septicemia while on heparin therapy was found to have a platelet-aggregating factor present in several plasma samples and in a sample of serum. This factor was subsequently shown to be an IgG with aggregating properties toward normal platelets that were enhanced by, but not dependent on, the presence of heparin. Further studies showed that heparin was unlikely to have acted as a hapten in initiating the IgG production but that its role was significant in aggravating the ensuing arterial thrombosis. The necessity of substitution of heparin with alternative anticoagulant/antithrombotic therapy to avoid the worst sequelae of this potentially catastrophic syndrome is discussed.

Blood Coagulation Factors↗

Erythrocyte sodium pump activity in human obesity.

In an attempt to resolve the prevailing confusion about erythrocyte sodium pump activity in obesity, we measured sodium-potassium-ATPase, ouabain-inhibitable (active) sodium efflux rate constant and intracellular sodium concentration in erythrocytes from 107 non-obese and obese subjects, with a body-mass index ranging from 17 to 54 kg X m-2. All the three independently measured variables were not significantly different between the two groups and no correlations were found between these three indices and body-mass index. The expression of ATPase activity in units of membrane protein allowed our previous data to be compared with this study and other reports. Our studies and most of the published reports suggest that there is no difference in erythrocyte sodium-potassium-ATPase and sodium transport between the vast majority of obese and non-obese subjects, but there is a subgroup of obese subjects (about 5%) with abnormally high erythrocyte sodium pump activity. The variable treatment of data from this subgroup and the small numbers of obese subjects studied by various investigators are largely responsible for the conflicting results about erythrocyte sodium pump activity.

Adult↗

Acquired factor XI inhibitors in two patients with hereditary factor XI deficiency.

Two patients with hereditary factor XI deficiency developed inhibitors following plasma transfusions. Neither had severe spontaneous bleeding. The patients' plasmas neutralized both factor XI in plasma, purified factor XI, and purified factor XIa. The inhibitor in both patients' plasmas adsorbed to Protein A-Sepharose. The inhibitors eluted from Protein A-Sepharose were partially neutralized by kappa and lambda light chain antisera indicating that they were polyclonal IgG antibodies. Both inhibitors markedly decreased adsorption of factor XI to glass surfaces. The cleavage of factor XI by trypsin was unaffected by the inhibitors. The lack of severe spontaneous bleeding in both of these patients strongly suggests that an alternate coagulation mechanism bypassing factor XI must compensate for this severe defect.

Blood Coagulation Tests↗

Effects of two benzodiazepines on the speed and accuracy of perceptual-motor performance in the elderly.

The daytime performance efficiency of 12 elderly subjects of average age 81.5 years (range 75-96 years) was examined in a cross-over study following lormetazepam 1 mg, nitrazepam 5 mg, and placebo capsules nightly for 7 nights. Performance was assessed on the Gibson spiral maze, and a reciprocal tapping task. In both tasks the speed and the accuracy of performance were independently measured. Performance testing sessions were conducted on the morning following the first, and the morning following the seventh dose of each of the three experimental treatments. Performance on the Gibson spiral maze showed no significant effect of either of the active drugs. On the reciprocal tapping task, speed was similarly unaffected by both drugs. However, while neither drug significantly affected overall accuracy after the first dose, nitrazepam but not lormetazepam significantly impaired overall accuracy after seven consecutive doses. This difference between nitrazepam and lormetazepam was significant. Further analyses showed nitrazepam consistently to be associated with impaired accuracy at both intermediate and high levels of task complexity. Lormetazepam, on the other hand, was associated with impairment only at the highest level of task complexity. The overall pattern of impairment associated with nitrazepam, but not with lormetazepam, was consistent with drug accumulation.

Aged↗

Effect of loprazolam and of triazolam on psychological functions.

Twelve poor sleepers of mean age 52 years performed 2 h of laboratory tests three times on 1 day during each week of nightly intake of loprazolam 0.5 mg, loprazolam 1 mg, triazolam 0.5 mg, or continued placebos. Only in the mornings did loprazolam 1 mg cause impairment in manual dexterity and card-sorting, and triazolam 0.5 mg in manual dexterity. Using difference from baseline, withdrawal of either drug after 3 weeks was associated with poorer subjective quality of sleep than following continuing placebos. The rate of spontaneous complaints (including accidents) associated with the drugs was as informative as formal testing.

Adult↗

IgG subclasses in collagen-induced arthritis in the rat.

Using a solid-phase double-antibody radioimmunoassay IgG antibodies to native bovine type II collagen were measured as total IgG and as subclasses of IgG (IgG1, IgG2a, IgG2b, IgG2c ) in arthritic and non-arthritic Sprague-Dawley rats. Statistically significant differences were observed between arthritic and non-arthritic animals for IgG1, IgG2a, IgG2b and total IgG. The significance of these results and their possible relevance to the human disease are discussed.

Animals↗

Changes in hypnotic usage in residential homes for the elderly: a longitudinal study.

The use of hypnotic drugs in 25 local authority homes for the elderly was recorded on a 1-day point prevalence study following a 6-mth monitoring programme involving all new admissions. From a total population of 1114 residents 390 (35%) were taking hypnotics on the night of the survey, showing a slight increase from similar surveys carried out in 1980 and 1981. The proportion of residents receiving hypnotics within each home varied from 0.0 to 61.8%. Correlation with levels of usage in the previous surveys was low, suggesting that pattern of hypnotic usage may change considerably over time within individual homes. Of the 156 residents who were admitted as permanent residents during the 6-mth period preceding the survey, 56 (35.9%) had been taking hypnotics on admission. Both the results of the drug monitoring programme and the survey show an association between hypnotic usage and source of admission: residents admitted from hospital being more likely to be taking sleeping tablets. A considerable change was found in the type of hypnotic currently prescribed with an increased preference being shown for short half-life hypnotics. A higher proportion of residents also were prescribed lower doses of hypnotics than previously, suggesting an increased awareness of the risks associated with hypnotic use in the elderly.

Aged↗