Biomedical subjects

C Howell

Publications and source records attributed to C Howell.

At least 19 recordsLinked to original sources

PubMed1998

The relationship between thiopurine methyltransferase activity and genotype in blasts from patients with acute leukemia.

The level of expression of the enzyme thiopurine methyltransferase (TPMT) is an important determinant of the metabolism of thiopurines used in the treatment of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Studies in red blood cells (RBC) have shown that TPMT expression displays genetic polymorphism with 11% of individuals having intermediate and one in 300 undetectable levels. The genetic basis for this polymorphism has now been elucidated and polymerase chain reaction (PCR)-based assays described for the most common mutations accounting for reduced activity. In previous studies, genotype has been correlated with red blood cell activity. In this report, we describe the relationship between genotype and TPMT activity measured directly in the target of drug action, the leukemic cell. We have demonstrated that the TPMT activity in lymphoblasts from 38 children and adults found by PCR to be homozygotes (*1/*1) was significantly higher than that in the five heterozygotes (*1/*3) detected (median, 0.25 v 0.08, P < .002, Mann-Whitney U). Similar results were obtained when results from children were analyzed separately. However, comparison of activity in blasts from AML and ALL showed a higher level in the former (0.35 v 0.22 nU/mg, P < .002, n = 17, 35), suggesting that factors other than genotype may also influence expression.

Acute Disease↗

PubMed1997

Methemoglobinemia associated with dapsone treatment in solid organ transplant recipients: a two-case report and review.

Dapsone, a sulfone antibiotic, has been increasingly used in solid-organ transplant recipients for the primary prevention of Pneumocystis carinii pneumonia, especially in patients with documented sulfa allergy. A known side effect of dapsone therapy, however, is methemoglobinemia, a condition leading to impaired tissue oxygen delivery. This report documents two cases of dapsone-induced methemoglobinemia in patients after solid organ transplantation with emphasis on the importance of clinical recognition and benefits of treatment. Further, the pathophysiology and causes of this condition are extensively reviewed.

Aged↗

PubMed1995

Conservative management of pediatric pancreatic pseudocyst using octreotide acetate.

Pancreatic pseudocysts in children are rare. A total of 213 cases have been reported in the literature, the majority secondary to trauma (65%). Treatment options range from conservative, non-operative management to operative drainage. Octreotide acetate, a long-acting analog of somatostatin, is a synthetic peptide with a variety of endocrine and gastrointestinal functions. Octreotide has been successfully used following pancreatic surgery to reduce exocrine function and most recently in the management of adult pancreatic pseudocysts. We report the efficacy of octreotide, as an adjunct to treatment, in two children with pancreatic pseudocyst. Each child was treated conservatively with bowel rest, hyperalimentation, and octreotide acetate (2.5 micrograms/kg SQ QD). Complete resolution of the pseudocysts occurred within 5 weeks. We conclude that octreotide acetate is a safe and potentially effective adjunct in the treatment of pediatric pancreatic pseudocyst, and should be added to the management of pseudocyst before drainage procedures.

Child↗

PubMed1991

Hiding and healing: resolving the suicide of a parent or sibling.

The purpose of this study was to describe the long-term effects of suicide of a parent or sibling during childhood or young adulthood. A grounded theory approach was used to discover the respondents' perceptions of the meaning of the event and the effects that it had on them. The themes that emerged from the data were experiencing the pain, hiding the pain, and healing the pain. The need to hide the pain often interfered with the process of healing the pain. Findings indicate that many survivors of suicide during childhood experience painful, unresolved grief that affects their well-being in adulthood.

Adaptation, Psychological↗

PubMed1990

The Mother-Infant Transaction Program. The content and implications of an intervention for the mothers of low-birthweight infants.

A brief, economic neonatal intervention based on the transactional model of development and influenced predominantly by the conceptual design of the Neonatal Behavioral Assessment Scale was implemented in an intensive care nursery with the mothers of a group of low-birthweight infants. The development of the intervention group was compared with that of a similar group of low-birthweight infants who did not receive the intervention and contrasted with that of a group of normal-birthweight infants. The intervention had a significant effect on maternal adjustment and perception of the infant at 6 months. No significant effect on infant cognitive development was apparent until 36 months (that is, 31 months after the intervention had ceased). The intervention effect was even more significant at 48 months. It appeared that the two low-birthweight groups had progressively diverged after 12 months, the intervention group rising until it approximated the normal-birthweight group in cognitive development, whereas the low-birthweight control group deteriorated. The economical nature of the MITP, its unique (although delayed) benefits, and the apparent durability of the intervention effect, suggest that this intervention program has important theoretical and practical implications and potentially far-reaching applications.

Child Development↗

PubMed1989

The significance of ductal shunting during extracorporeal membrane oxygenation.

The purpose of this study was to evaluate the significance and direction of shunts at the level of the foramen ovale or ductus arteriosus in full-term newborns with neonatal respiratory failure who were placed on extracorporeal membrane oxygenation (ECMO). A decrease in left ventricular dimension was expected when infants were placed on ECMO but did not occur. A left-to-right shunt was demonstrated at the ductal level in nine of 12 infants early in the course of ECMO before pulmonary resistance decreased. Presumably, the lack of change in the left ventricular dimension when infants were placed on bypass was due to a left-to-right shunt at the ductal level with ductal flow replacing the right heart output, being drawn into the bypass circuit.

Ductus Arteriosus, Patent↗

PubMed1986

A mouse model for the study of necrotizing enterocolitis.

A mouse model for the study of necrotizing enterocolitis is presented. It is a model of temporary intestinal ischemia and consists of occluding both superior mesenteric vessels with a bulldog clamp for varying periods of time. The resultant lesions resemble the intestinal lesions seen in necrotizing enterocolitis in respect to the gradual development of the necrotizing lesions and their patchy distribution. We also studied the effect of intravenous saline and low molecular weight dextran in preventing the development of these ischemic lesions. In moderate ischemia, saline and dextran show a similar protective effect, and in severe ischemia, both show a protective effect, with dextran being more effective than saline.

Animals↗

PubMed1984

Epidemiology of peptic ulcer in Australia. A study based on government statistics in four states.

A study of Pharmaceutical Benefits Scheme cimetidine prescriptions, hospital admissions, and deaths due to peptic ulcer in 13 million Australians in 1981 indicated that the annual ulcer incidence per 1000 population was 3.8 for duodenal ulcer and 0.7 for gastric ulcer. Approximately 70 000 Australians appear to receive initial treatment for a peptic ulcer each year. Two-thirds of patients were managed outside hospital. Patients with gastric ulcers were more likely to be admitted to hospital or to die from their ulcer than were patients with duodenal ulcers. Significant regional differences in ulcer frequency were found; in particular, the risk of gastric ulcer in NSW was four times that in Victoria. Gastric and duodenal ulcers were more common in New South Wales than in Victoria, Queensland or Western Australia. These differences, and other regional variations, indicate appropriate localities for further studies of the aetiology of peptic ulcer.

Adolescent↗

PubMed1984

Synovectomy as treatment for purulent joint infection.

Conventional treatment of pyogenic knee joint infections leads to unsatisfactory results. Through early synovectomy, before cartilage damage and osteoarthritis appear, the infected focus can be "excised." Functional after-treatment avoids cartilage atrophy, wound adhesions, and muscle weakness. The excellent results after 26 knee joint infections confirm this.

Adolescent↗

PubMed1983