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Biomedical subjects

J W Hanson

Publications and source records attributed to J W Hanson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Autosomal recessive cerebellar hypoplasia.

Cerebellar hypoplasia is found in association with a variety of neurologic and systemic disorders. It is the primary finding in the uncommonly reported condition of autosomal recessive cerebellar hypoplasia. We describe two siblings with cerebellar hypoplasia documented in both by magnetic resonance imaging (MRI) and review the clinical features of previously reported cases of autosomal recessive cerebellar hypoplasia. The most common findings in this disorder are nonprogressive ataxia, strabismus, mental retardation, and speech delay with dysarthria. Previously reported cases have been confirmed by autopsy, pneumoencephalography, or computed tomographic (CT) scans. MRI clearly documents diffuse cerebellar hypoplasia and aids in distinguishing autosomal recessive cerebellar hypoplasia from other disorders. The pathophysiology of this disorder is uncertain, however, studies of the weaver mutant mouse (an animal model of autosomal recessive cerebellar hypoplasia) suggest that an abnormality of the Bergmann glia may lead to the observed granule cell layer deficiency in these patients. This diagnosis should be considered for children with nonprogressive ataxia and families should be made aware of the 25% recurrence risk.

Cerebellar Diseases↗
PubMed1988

Independent dysmorphology evaluations at birth and 4 years of age for children exposed to varying amounts of alcohol in utero.

Two groups of 4-year-old children were examined by a dysmorphologist without knowledge of previous examination results or prenatal exposure and categorized as to whether or not they showed fetal alcohol effects. A priori classification of children into the two groups was on the basis of their mothers' self-report of drinking when interviewed during pregnancy. Children born to 108 mothers in a "heavier" drinking group (absolute alcohol concentration greater than or equal to 30 mL/d [1.0 oz/d]) were compared with a matched group of children born to 97 mothers whose average absolute alcohol concentration was less than 0.3 mL/d (0.01 oz/d). The percentage of children with fetal alcohol effects in the heavier drinking v the comparison group was 20.4% v 9.3%. When fetal alcohol effects were studied in relation to only the absolute alcohol concentration scores, there was a significantly greater chance of a child being classified as having fetal alcohol effects with increasing levels of alcohol exposure prior to recognition of pregnancy (P = .013). A logistic regression, run on the absolute alcohol concentration scores and other primary exposures, indicated that fetal alcohol effects classification was not significantly related to nicotine, caffeine, or marijuana but was significantly related to absolute alcohol concentration scores even after statistically adjusting for these other exposures (P = .002). Classification of fetal alcohol effects at 4 years of age was compared to a fetal alcohol effects classification obtained at birth by an independent dysmorphologist in a sample of 75 subjects examined at both ages, and 80% of the infants classified as having fetal alcohol effects at birth were classified as having fetal alcohol effects at 4 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Maternal exposure to spermicides in relation to certain birth defects.

Several studies have found no increase in the overall frequency of birth defects in association with the use of spermicides, but the possibility of an increase in specific defects remains. We evaluated this possibility in a large case-control study. Infants with certain malformations (265 with Down's syndrome, 396 with hypospadias, 146 with limb reduction defects, 116 with neoplasms, and 215 with neural-tube defects) were compared with 3442 control infants with a wide variety of other defects. Exposure to spermicides was assessed for three periods: use during the periconceptional period (one month before through one month after the last menstrual period), use during the first trimester (the first four lunar months of pregnancy), and any use during the lifetime. For the five groups of cases and for each interval, the odds ratios were close to 1.0 (range, 0.7 to 1.3); the upper 95 percent confidence bounds were 2.2 or lower. Risks did not increase with the duration of exposure. When each of the active ingredients in currently available spermicides was considered separately, no differences in odds ratios were apparent between the types of spermicides. With the possible exception of a subgroup of cases (limb reduction defects of unknown cause), these results suggest that risks for the five specific birth defects evaluated are not increased by exposure to spermicides.

Abnormalities, Drug-Induced↗
PubMed1987

Dominantly inherited dilated cardiomyopathy.

We describe a family in which there is segregating an autosomal dominant gene determining a cardiomyopathy. The pathodynamics is that of pump failure associated with dilatation of the heart, generally having an overt clinical onset from the fourth through seventh decades. Dysrhythmia is a frequent concomitant feature. There may be an associated skeletal myopathy, either producing a very mild proximal weakness or proving detectable only upon biopsy. This family is similar to other reported cases of familial dominant "idiopathic" dilated cardiomyopathy, but the nature of the heterogeneity within this category remains to be elucidated. The roles of echocardiography, cardiac biopsy, and skeletal muscle biopsy in the presymptomatic detection of the heterozygote are noted.

Adolescent↗
PubMed1986

Further delineation of Weaver syndrome.

Seven new cases of Weaver syndrome are described, including the first reported case in an adult. Overgrowth is usually but not always present. The combination of characteristic facies and developmental delay, with the peculiar radiographic findings of accelerated dysharmonic osseous maturation and splaying of the distal long bones, is diagnostic of Weaver syndrome.

Adult↗
PubMed1985

Factors influencing maternal estimates of genetic risk.

The relationship between the objective and subjective estimates of genetic risk was studied in 202 women accepting and 50 women not accepting amniocentesis. All women were at risk of having a child with congenital anomalies either because of maternal age at pregnancy or family history of Down syndrome (DS) or other congenital anomalies. Only 28.6% of the women rejecting and 44.4% of the women accepting amniocentesis remembered correctly their objective odds. The correlations between the objective risk estimates and the subjective risk estimates were low overall (r = 0.089, p = 0.08); for women rejecting (r = 0.024, p = 0.44) or accepting (r = 0.082, p = 0.12) amniocentesis. The psychosocial and sociodemographic variables relating to either objective or subjective risk estimates were different for both groups of women. The study provides information on variables that should be taken into consideration in formulating a general theory to predict individual perceptions of genetic risk.

Adult↗
PubMed1984

Purification and characterization of chicken erythrocyte ferrochelatase.

Ferrochelatase (EC 4.99.1.1) was purified 2000-fold to apparent homogeneity from isolated chicken erythrocyte mitochondria. The purified enzyme yields a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with an apparent Mr of 42 000. The enzyme utilizes proto-, meso- and deutero-porphyrin with Km values of 37, 51 and 80 microM respectively. The disubstituted porphyrins 2,4-bisglycol deutero-porphyrin and 2,4-disulphonic deuteroporphyrin were not substrates. Mn2+, Hg2+, Pb2+ and Co2+ were strong inhibitors of the purified enzyme. Palmitic acid and oleic acid stimulated activity, whereas linoleic acid inhibited and phospholipids had variable effects. Chicken ferrochelatase was inhibited by N-ethylmaleimide and iodoacetamide. Inhibition by iodoacetamide was pseudo-first-order, but inhibition by N-ethylmaleimide appeared to be biphasic in nature with an initial high rate followed by a much lower rate of inactivation. The characteristics of the chicken erythrocyte enzyme are compared with those previously reported for mammalian liver ferrochelatase.

Animals↗
PubMed1984

Börjeson-Forssman-Lehmann syndrome: further delineation in five cases.

We have studied five males with Börjeson-Forssman-Lehmann syndrome (BFLS) from two unrelated families. They had a characteristic facial appearance with prominent supraorbital ridges, deep-set eyes, ptosis, and large ears, as well as obesity, severe mental retardation, hypotonia, and hypogonadism. Ophthalmologic, EEG, and skeletal abnormalities were also present. The findings in several presumed or possible heterozygous women were evaluated and suggested a wide range of phenotypic effects varying between apparent normality to mild or moderately evident BFLS manifestations. The observed pattern of occurrence of the BFLS in our two families provides strong support for X-linked inheritance. In clinically normal female relatives at risk for being carriers of BFLS, we have been unsuccessful in identifying a reliable screening test. The condition in our and previously reported patients was contrasted with other malformation syndromes and our findings support the conclusion that BFLS is a distinct and clinically identifiable disorder.

Abnormalities, Multiple↗
PubMed1983

First report of mosaic trisomy 12 in a liveborn individual.

Trisomy 12 mosaicism was found in a 36-year-old woman with minor anomalies, neuromuscular abnormalities, and moderate mental retardation. Trisomy 12 was present in 13% of the lymphocytes but not in skin fibroblasts. Previous reports of dup (12p) and dup(12q) are reviewed. To our knowledge this is the first report of a "complete" trisomy 12 in a liveborn individual.

Abnormalities, Multiple↗
PubMed1983

Abnormality of chromosome 11 in patients with features of Beckwith-Wiedemann syndrome.

Two unrelated children with features of Beckwith-Wiedemann syndrome have been found to have partial duplication of chromosome 11p. A review of six other reported cases of partial duplication of 11 p revealed features of this syndrome not previously recognized. We suggest that karyotype studies with banding techniques should be done in children with features of Beckwith-Wiedemann syndrome and developmental delay or retardation.

Beckwith-Wiedemann Syndrome↗
PubMed1983

Holoprosencephaly in infants of diabetic mothers.

We report seven infants of diabetic mothers, affected with holoprosencephaly malformation sequence. An additional 15 cases assembled from personal communications and the literature indicate that holoprosencephaly, like neural tube, cardiac, and caudal defects, is specifically increased in children of diabetic mothers. Incidence figures from newborn surveys demonstrate a risk for holoprosencephaly in infants of diabetic mothers comparable to the 1% risk for caudal regression malformation sequence. The embryologic timing of cranial, cardiac, and caudal defects emphasizes the need for pregnancy planning and diabetes control.

Abnormalities, Multiple↗