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Biomedical subjects

R Harper

Publications and source records attributed to R Harper.

125 records · Page 7Linked to original sources

Effect of coexistent coarctation of pulmonary trunk in natural history of complete absence of pulmonary valve with ventricular septal defect.

A case of complete absence of the pulmonary valve in association with a ventricular septal defect and a pulmonary artery coarctation is described. Despite these defects the patient had minimal symptoms, probably because the pulmonary artery coarctation acted as a natural banding and limited the pulmonary regurgitant flow and reduced the left-to-right shunt across the ventricular septal defect. The patient was operated on at the age of 40 and the ventricular septal defect was closed but the pulmonary artery coarctation was left alone. In view of the long-term survival in this case, it is suggested that pulmonary artery banding would reduce the symptoms and increase the life expectancy of patients with congenital absence of the pulmonary valve and a ventricular septal defect.

Adult↗

Achieving optimal diabetic control in adolescence: the continuing enigma.

The transition from childhood through adolescence to adulthood is a difficult stage, particularly for patients with type 1 diabetes. The yearning for autonomy and independence, as well as the hormonal changes around the time of puberty, can manifest in poor glycaemic control. The focus on diet and weight increases the prevalence of eating disorders, compounding the difficulties in supervising diabetes patients. This can be exacerbated by the realisation that hyperglycaemia induces weight loss and the use of this knowledge to further manipulate diabetes control to gain a desired body image. The management of adolescents with type 1 diabetes is therefore challenging and requires close collaboration between psychological medicine and diabetes teams. This review describes the difficulties frequently encountered, with a description of four cases illustrating these points. Case 1 demonstrates the problem of needle phobia in a newly diagnosed patient with type 1 diabetes leading to persistent hyperglycaemia, the recognition of weight loss associated with this and the development of bulimia. The patient's overall management was further complicated by risk-taking behaviour. By the age of 24 years, she has developed diabetic retinopathy and autonomic neuropathy and continues to partake in risk-taking behaviour. Case 2 illustrates how the lack of parental support shortly after the development of type 1 diabetes led to poor glycaemic control and how teenagers often omit insulin to accommodate lifestyle and risk-taking behaviour. Case 3 further exemplifies the difficulty in managing patients with needle phobia and the fear of hypoglycaemia. Case 4 adds further weight to the need for parental support and the impact of deleterious life events on glycaemic control by manipulation of insulin dosage.

Adolescent↗

Nonsyndromatic paucity of interlobular bile ducts: light and electron microscopic evaluation of sequential liver biopsies in early childhood.

Liver biopsies and/or autopsy specimens from 17 children (ages 1 week to 5 years) with nonsyndromatic paucity of the interlobular bile ducts were studied by light and electron microscopy. Initial biopsies were obtained before 90 days of age from all patients, and two or more specimens were available from nine. No specific underlying condition was found in nine infants. The remaining cases were associated with Down's syndrome (n = 2), hypopituitarism (n = 2), cystic fibrosis (n = 1), alpha 1-antitrypsin deficiency (n = 1), cytomegalovirus (n = 1) and Ivemark syndrome (n = 1). Before 90 days of age, portal changes included duct paucity and fibrosis. Lobular changes were nonspecific, consisting of cholestasis, giant cell transformation, extramedullary hematopoiesis and perisinusoidal fibrosis. Duct paucity, portal fibrosis and perisinusoidal fibrosis persisted after 90 days. Cholestasis was mild or no longer apparent. Portal changes before 90 days of age appear to be sufficiently distinctive to microscopically distinguish nonsyndromatic from syndromatic paucity. Electron microscopic findings suggest that paucity in nonsyndromatic patients may result from a primary ductal insult: ultrastructural studies revealed bile duct destruction characterized by undulation and breaks in the basal lamina and infiltration of the epithelium by lymphocytes. Bile canalicular dilatation with blunting of microvilli and electron-dense material in the lumen, predominantly seen before 90 days, also reinforces the hypothesis of a primary ductal defect.

Age Factors↗

Patent foramen ovale and cryptogenic cerebral infarction.

The patent foramen ovale (PFO) has been increasingly implicated in the aetiology of stroke, particularly in young patients with no other identifiable cause (cryptogenic stroke). The mechanism is by the passage of venous clots through the patent foramen into the arterial circulation, enabling cerebral embolism. Such patients with cryptogenic stroke and PFO are often treated with life-long anticoagulants or antiplatelet agents in an attempt to decrease the risk of a recurrence. Less commonly, surgical closure of the PFO has been undertaken in these patients. However, the recent evolution of closure devices that are delivered percutaneously by standard cardiac catheter techniques now offer an alternative non-surgical option. These alternative therapies are yet to be compared adequately. Two issues remain to be resolved. First, in determining appropriate therapy, patients with cryptogenic stroke may be divided into three groups: those with no PFO but an alternative unrecognized aetiology, those with an 'innocent' PFO and an alternative unrecognized aetiology and those with a causative PFO. The distinction between these groups clearly has important treatment implications. Second, the risk versus benefit of each available treatment modality must be determined for these different patient subgroups. These two issues require resolution before rational evidence-based treatment can be prescribed for patients with PFO and cryptogenic stroke.

Cerebral Infarction↗

Fixation techniques for fine needle aspiration biopsy smears prepared off site.

OBJECTIVE: To identify a simple, cost-effective, reliable fixation method for fine needle aspiration biopsy (FNAB) yielding a specimen suitable for mail transport. STUDY DESIGN: Smears prepared from 59 FNABs of surgical specimens were fixed by continuous fixation in 95% ethanol, spray fixation, air drying, ethanol fixation for either 5 minutes or 4 hours followed by spray fixation, or fixation in 95% ethanol for either 30 minutes or 4 hours followed by air drying. Fixation was graded as unsatisfactory, suboptimal, average, good or excellent. RESULTS: Of smears continuously fixed in ethanol, 96.6% were graded as excellent. Of smears fixed in ethanol followed by spray fixation, 93.2% were excellent irrespective of fixation time; 64.4% of spray-fixed smears were excellent and 27.1% good. Of air dried smears, 93.2% were unsatisfactory or suboptimal; 83.0% of smears fixed in ethanol for 30 minutes and 74.6% of smears fixed for 4 hours prior to air drying were unsatisfactory or suboptimal. CONCLUSION: Fixation of smears in 95% ethanol followed by spray fixation produces excellent results, comparable to those with continuous fixation in ethanol. Spray fixation is generally good but not consistently excellent. Air drying or fixation in ethanol followed by air drying yields unsatisfactory or suboptimal results in most cases.

Biopsy, Needle↗