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Biomedical subjects

R M Bannerman

Publications and source records attributed to R M Bannerman.

At least 37 records · Page 2Linked to original sources

Familial pulmonary atresia. Its occurrence with a ventricular septal defect.

To our knowledge, this is the first reported case of pulmonary atresia with a ventricular septal defect that occurred in a father and his son. A multifactorial mode of determination that resulted from an interaction between genetic predisposition and environmental factors was assumed, since the family history did not show other members with congenital heart defects. Based on the background and on information from the multifactorial theory of inheritance, a counseling plan was formulated for these parents. A similar approach is recommended for the many surgical survivors of previously uncorrectable complex congenital heart defects as they approach reproductive age.

Abnormalities, Multiple↗

Benign prostatic hyperplasia in an XX man.

A sixty-nine-year-old white phenotypic male who was being investigated for a myeloproliferative disorder, was found to have an XX karyotype in all cells examined in bone marrow, lymphocytes, and skin fibroblast cultures. Despite essentially no testosterone in the plasma, he also suffered from severe prostatic hyperplasia, a finding not reported previously in patients with this genotype. While endocrine studies showed normal follicle-stimulating hormone, the luteinizing hormone level was twice the upper limit of normal and estrogens were in the normal female range. Except for complete absence of Leydig cells, testicular histology resembled that usually found in Klinefelter syndrome. The patient died of the combined effects of the myeloproliferative disease and urinary tract obstruction. The mechanism of occurrence of the sex chromosome anomaly as well as the cause and implication of the unusual finding of prostatic hyperplasia are discussed.

Aged↗

Determinants of haemoglobin level in sickle cell-haemoglobin C disease.

The determinants of steady state haemoglobin levels in sickle cell-haemoglobin C (SC) disease were investigated by measuring routine haematological and biochemical indices, red cell survival, oxygen affinity, pitted erythrocytes, and red cell and plasma volumes in 31 adult patients (15 male; 16 female). Red cell survival was shortened in all subjects, and was positively correlated with haemoglobin level. However, many haemoglobin values were within the normal range, especially in male subjects. Palpable splenomegaly, which occured in 53% of patients, did not appear to affect haemoglobin level, red cell survival, plasma volume, or red cell volume, but was associated with lower platelet counts and decreased pitted red cells. Sex related differences were found in total haemoglobin, packed cell volume, conductivity cell volume, red cell count, and in the blood volume measurements. Red cell, plasma and total blood volumes in patients varied with weight and cube of height in manner observed in normal subjects, although red cell volumes were lower and plasma volumes were greater than in normal subjects of given height and weight. Anaemia in SC disease is related to the haemolytic rate but the major determinant appears to be an inappropriate increase in plasma volume.

Adolescent↗

An infant with trisomy 9pter yields 9q22 resulting from 3:1 segregation in a 46,XX t(1;9) (p36;q22) mother.

A newborn infant with a 47,XY,+ der(.),t(1;9) (p36;q22)mat chromosome complement and the clinical features of the 9p trisomy is described. A review of the reproductive histories of five cases with trisomy 9pter yields 9q21 or 22 indicate that the balanced translocation mothers of these infants may have as high as a 23% chance of producing a chromosomally unbalanced offspring due to 3:1 disjunction.

Adult↗

Chromosome analysis in cases with repeated spontaneous abortions.

G-banded chromosome complements were analyzed from couples and individuals who had experienced 3 unexplained spontaneous abortions. One woman was found to be a carrier of a t(13q14q) chromosome; all other subjects had normal-appearing karyotypes. Banded chromosome studies are recommended for couples with repeated abortions in the absence of any apparent cause.

Abortion, Habitual↗

Duplication 2q33 leads to 2q37 due to paternal ins (12;2) translocation.

An 18 month-old boy with partial duplication of the long arm of chromosome 2, based on a paternal balanced translocation, 46,XY,ins (12,2)( q23;q33q37), is described and compared with five previously reported cases. These children have in common a short nose with broad flat bridge and small anteverted nostrils, long upper lip, low-set ears, and minor digital anomalies.

Abnormalities, Multiple↗

Iron deficiency anaemia in newborn sla mice: a genetic defect of placental iron transport.

Newborn mice with X-linked anaemia (gene symbol sla) have lower haemoglobin levels at birth than normal and carrier mice but there is considerable overlap. Serial observations showed that the haemoglobin values of segregating male mice separate into a bimodal distribution of 42 d of age, and 50 d values were used to assign genotypes retrospectively. The anaemia in newborn sla mice is attributable to iron deficiency, since their total body iron is lower than in normal newborn mice, while their birth weights are almost identical. Haemoglobin levels at birth in normal, anaemic and carrier mice are also influenced by the mother's genotype and phenotype, and the haemoglobin value was progressively lower according to the sla gene dose of the mother. Materno-fetal iron transfer was examined by labelling pregnant carrier females with radioiron in various ways. When given as single or intermittent doses by injection no clearcut differences emerged in apparent iron transfer to anaemic as compared to non-anaemic fetuses. However, when radioiron was administered continuously in food a significant reduction in iron transfer to anaemic fetuses was demonstrated. The sla gene is already known to have a major effect in reducing iron transport in the small intestine. The present studies provide evidence of an analogous defect in placental iron transport.

Anemia, Hypochromic↗

A new familial syndrome characterized by pigmentary retinopathy, hypogonadism, mental retardation, nerve deafness and glucose intolerance.

Three siblings with retinitis pigmentosa, deafness and mental retardation were studied. Physical abnormalities included nystagmus, acanthosis nigricans and multiple keloids. The two male siblings had gynecomastia, small testes and mild subvirilization whereas the only indication of hypogonadism in the female sibling was oligomenorrhea. Testosterone levels in the males, which were in the low to low normal range, were increased by the administration of large doses of chorionic gonadotropin. The two affected males had elevated plasma luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels which were decreased by the administration of testosterone and increased by the administration of clomiphene. One sibling had mild obesity and diabetes mellitus, one had moderate obesity, normal glucose tolerance and hyperinsulinism and the third had abnormal glucose tolerance and hyperinsulinism. This familial syndrome is distinct from either the Laurence-Moon, Bardet-Biedl or Alström disorders and provides further evidence of genetic heterogeneity in this group of autosomal recessive traits.

Adolescent↗

Non-disjunction of an unusual X chromosome.

Because of multiple abnormalities in her children, a young mother was investigated and shown to have a 47,XXX chromosome constitution. Additional C group chromosomes without visible centromeric constrictions were found in a number of cells from the peripheral blood, and using C and Q banding techniques these chromosomes were identified as X chromosomes. Analysis of the banding karyotypes of 300 cells revealed that the acentric X chromosomes had the ability to replicate and that this replication was associated with non-disjunction leading to aneuploid cells. Even though cultured skin cells did not have acentric or extra chromosomes in addition to the triple-X, examination of buccal mucosa cells for the presence of X-bodies suggested that the phenomenon of non-disjunction was present in the epithelial cells of the patient. In addition to the X without a visible centromeric constriction, either acentric D or E chromosomes were found. The data suggest that a functional defect in the cells per se is responsible for the appearance of the acentric chromosomes.

Adult↗

Genetic defects of iron transport.

Five genetic traits in man and laboratory animals have major effects on iron transport. The heterogeneous condition, hemochromatosis, in some families appears to segregate as a Mendelian trait, and is associated with defective control of intestinal iron absorption. In the very rare human autosomal recessive trait, atransferrinemia, there is an almost total lack of transferrin and gross maldistribution of iron through the body. In mice, sex-linked anemia (an X-linked recessive trait) causes iron deficiency through defective iron absorption, at the "exit" step; a similar defect probably exists in placental iron transfer. In microcytic anemia of mice, an autosomal recessive trait, iron absorption is also impaired because of a defect of iron entry into cells, which is probably generalized. Belgrade rat anemia, less understood at present, also may involve a major disorder of iron metabolism. Study of these mutations has provided new knowledge of iron metabolism and its genetic control Their phenotypic interaction with nutritional factors, especially the form and quantity of iron in the diet, may provide new insights for the study of nutrition.

Age Factors↗