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Biomedical subjects

R Howell

Publications and source records attributed to R Howell.

At least 55 records · Page 3Linked to original sources
PubMed1981

Ultrastructure of muscle in fetal Duchenne's dystrophy.

Skeletal muscle was studied from two male fetuses with Duchenne's muscular dystrophy (DMD) that were at 17 and 23 weeks' gestational age, respectively. In comparison with the ultrastructure of normal fetal muscle, a spectrum of changes could be seen, from normal-appearing to very degenerated fibers. The changes followed an apparent progression from early actin filament disruption and fraying of the Z bands to progressive disorganization of myofibrillar alignment, increasing vacuolization, and condensation of fibers. Significant plasma membrane defects were not found. These findings are similar to those described in older persons with DMD and confirm that DMD is a congenital disorder associated with consistent skeletal muscle changes in utero.

Female↗
PubMed1980

Partial monosomy of long arm of chromosome 4 due to interstitial deletion.

A child with congenital malformations and a de novo interstitial deletion of the long arm of chromosome 4 is described. Detailed analysis by G banding revealed the loss of the whole of band q21 and part of bands q13 and q22. The clinical abnormalities are quite dissimilar from those features described in other cases of partial 4q monosomy, which generally appear to result from the deletion of more distally placed segments of the chromosome.

Abnormalities, Multiple↗
PubMed1977

Influence of p-chloroamphetamine on female sexual reflexes and brain monoamine levels.

The effect of p-chloroamphetamine(PCA) on female sexual reflexes was biphasic. Administration of PCA to receptive females initially terminated ongoing sexual behavior and this effect was correlated with the release of monoamines, particularly serotonin (5-HT). Sexual reflexes were abolished within 15 min of PCA injection. Other reflexes, including reciprocal forepaw treading, lateral head weaving, hindlimb abduction and Straub tail, were elicited by PCA. The long term infuence of PCA was the opposite. A facilitation of female sexual behavior occurred accompanied by a relatively specific depletion of 5-HT (10 mg/kg, 66% depletion; 20 mg/kg, 80% depletion) with both dopamine and norepinephrine depleted by less than 15%. This long term facilitation of female sexual reflexes was not blocked by dexamethazone suggesting that PCA was acting directly on the neural substrate for mating and did not produce it facilitation via adrenal progesterone. This biphasic infuence of PCA on mating reflexes, paralleling its effect on monoamine transmission, suggests serotonergic involvement in the integration of mating behavior.

Amphetamines↗
PubMedDate not supplied

Cytomegalovirus infection in children with AIDS.

Data for 38 children perinatally exposed to human immunodeficiency virus (HIV) were evaluated to determine the impact of cytomegalovirus (CMV) infection on the course of perinatally acquired HIV infection. Thirteen children belonged to the P0 (indeterminate) group, one to the P1 (asymptomatic) group, and 24 to the P2 (symptomatic) group, per the classification of the Centers for Disease Control. Of the 24 children in the P2 group, 10 died. The mean follow-up time was 22.8 months for the 10 children who died and 16.3 months for the 13 children in the P0 group. Serial cultures of urine were performed for all 38 patients. CMV was isolated from seven of 10 children who died and from four of 14 children who survived (P less than .05). Only one of the 13 P0 children was culture-positive for CMV, as compared with 11 of 24 P2 children (P less than .05). All CMV-infected children continued to demonstrate CMV viruria in serial cultures. The mean age at the time of the first culture positive for CMV was 13 months. Microcephaly was present in 15 (65%) of 23 P2 children but in none of the P0 and P1 children (P less than .05). Eight of 11 CMV-infected children were microcephalic; seven of 12 children not infected with CMV were microcephalic (P greater than .05). These data suggest that the prevalence of active CMV infection is significantly higher in P2 children than in P0 and P1 children. In addition, there is a significant association between CMV infection and mortality among P2 children.

Acquired Immunodeficiency Syndrome↗