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Biomedical subjects

Helen Wallace

Publications and source records attributed to Helen Wallace.

9 recordsLinked to original sources
PubMed2006

Tongue tie division in infants with breast feeding difficulties.

OBJECTIVE: Tongue tie is a congenital oral abnormality characterised by an abnormally short lingual frenulum. The majority of current medical and surgical opinion is that tongue tie rarely, if ever, causes feeding difficulties and therefore, should not be divided. With increased popularity of breast feeding in the last decade there has been renewed interest in tongue tie and its effect on breast feeding. We present a case series of infants who underwent tongue tie division for feeding difficulties and assess the indications for and outcomes of the procedure. METHODS: Eleven infants with breast feeding difficulties associated with tongue tie underwent tongue tie division using a standard technique in the outpatient clinic. No anaesthetic or analgesia was used and there was little or no bleeding or infant distress. Parents were subsequently contacted by phone at least 4 months after the procedure to inquire about the effect of the procedure on feeding and any complications encountered. RESULTS: The age at tongue tie division ranged from 2 to 31 days (median=10 days). 10/11 of these infants were followed up. The age at follow up was 4-20 months (median=10 months). Prior to division, all mothers had attempted breast feeding and were keen to continue. 9/10 had experienced difficulties due to poor latch (8/10), sore nipples (6/10) and continual feeding cycle (5/10). Only 3/10 mothers were breast feeding exclusively. Following tongue tie division, an improvement in breast feeding was noticed immediately by 4/10 mothers. Three mothers did not notice any improvement. 6/10 mothers successfully breast fed for at least 4 months. There were no reported complications of the procedure. CONCLUSIONS: The benefits of breast feeding are well known and lactation consultants are becoming more aware of tongue tie as a treatable cause of breast feeding difficulty. The procedure is quick and simple, not requiring any analgesia or anaesthesia and can be performed in the outpatient clinic. Although not conclusive, this case series suggests a possible benefit of tongue tie division in symptomatic infants.

Adult↗
PubMed2006

Pulmonary edema in meningococcal septicemia associated with reduced epithelial chloride transport.

OBJECTIVES: To test the hypothesis that meningococcal septicemia-related pulmonary edema is associated with a systemic abnormality of epithelial sodium and chloride transport and to investigate an association with hormones regulating Na transport. DESIGN: Prospective observational study. SETTING: The 24-bed pediatric intensive care unit and pediatric wards of Royal Liverpool Children's Hospital. PATIENTS: Consecutive children admitted to the pediatric intensive care unit and pediatric wards with a diagnosis of meningococcal septicemia and children (controls) with noninfectious critical illness receiving ventilatory support in the pediatric intensive care unit. MEASUREMENTS AND MAIN RESULTS: We measured sweat and saliva electrolytes, renal electrolyte excretion, nasal potential difference, and aldosterone, thyroxine, and cortisol levels. Pulmonary edema was diagnosed by chest radiography and its severity quantified by calculation of ventilation index at admission and duration of mechanical ventilation. We recruited 17 patients with severe meningococcal septicemia (nine patients with pulmonary edema), 14 patients with mild meningococcal septicemia, and 20 controls. Sweat and saliva Na and Cl concentrations and renal Na excretion were significantly (p < .05) higher in patients with pulmonary edema compared with controls. Nasal potential difference and amiloride response in patients with pulmonary edema were not significantly different to controls, but response to a low Cl solution was reduced in the nasal airway of patients with pulmonary edema (p < .05). Sweat and saliva chloride concentrations correlated significantly and better with ventilation index and duration of ventilation than sodium concentrations. Aldosterone, thyroxine, and cortisol levels were not significantly different between groups. CONCLUSIONS: We have confirmed that meningococcal septicemia-related pulmonary edema is associated with reduced systemic sodium and chloride transport. Features of reduced Cl transport were most closely associated with markers of respiratory compromise, and this was supported by the reduced chloride channel function detected on nasal potential difference measurement.

Aldosterone↗
PubMed2004

Pharmacogenetics: ethical problems and solutions.

Regulators, drug companies, academic scientists, bioethicists, clinicians and, increasingly, the general public are starting to realize that pharmacogenetics (PGx) will probably have a huge impact on the way in which we treat both common and rare diseases. But how much thought has gone into the ethical issues that the incorportation of phamacogenetic testing into drug discovery, prescription and use will entail? It seems that "quite a bit" is the answer, as the diverse viewpoints of representatives of all of these groups presented here illustrate. However, these views also highlight that now is the time to start formulating and implementing solutions to these potential problems.

Ethics, Medical↗
PubMed2003

The origin of cortical surround receptive fields studied in the barrel cortex.

The neocortex is thought to be organized into functional columns of neurons, each of which processes an element of a larger representation. In the barrel cortex, the thalamic input to the column preferentially terminates in a barrel. To study the extent and nature of functional connections between columns, we measured the degree to which whisker responses are relayed between columns in the barrel cortex. Inactivating a single barrel by iontophoresis of the GABA(A) agonist muscimol abolished the representation of that barrel's whisker in neighboring barrels. Reactivating a single barrel by iontophoresis of the GABA(A) antagonist bicuculline while the rest of the cortex was blocked by muscimol led to single whisker receptive fields. Under the same conditions, septal cells tended to exhibit multiwhisker receptive fields. These studies demonstrate that the surround receptive fields of barrel cells are generated by intracortical transmission and that many septal cells derive a component of their surround receptive field from the thalamus.

Anesthetics↗
PubMed2002

Is there a thalamic component to experience-dependent cortical plasticity?

Sensory deprivation and injury to the peripheral nervous system both induce plasticity in the somatosensory system of adult animals, but in different places. While injury induces plasticity at several locations within the ascending somatosensory pathways, sensory deprivation appears only to affect the somatosensory cortex. Experiments have been performed to detect experience-dependent plasticity in thalamic receptive fields, thalamic domain sizes and convergence of thalamic receptive fields onto cortical cells. So far, plasticity has not been detected with sensory deprivation paradigms that cause substantial cortical plasticity. Part of the reason for the lack of thalamic plasticity may lie in the synaptic properties of afferent systems to the thalamus. A second factor may lie in the differences in the organization of cortical and thalamic circuits. Many deprivation paradigms induce plasticity by decreasing phasic lateral inhibition. Since lateral inhibition appears to be far weaker in the thalamus than the cortex, sensory deprivation may not cause large enough imbalances in thalamic activity to induce plasticity in the thalamus.

Animals↗