Biomedical subjects

P Kochhar

Publications and source records attributed to P Kochhar.

3 recordsLinked to original sources

PubMed1999

Guideline for the management of pediatric idiopathic constipation and soiling. Multidisciplinary team from the University of Michigan Medical Center in Ann Arbor.

OBJECTIVE: To develop an evidence-based guideline for the primary pediatric care of children (birth to 18 years old) with idiopathic constipation and soiling. DATA SOURCES: References were identified through a MEDLINE search from January 1975 through January 1998 to address 3 focus questions: (1) the best path to early, accurate diagnosis; (2) best methods for adequate clean-out; and (3) best approaches to promote patient and family compliance with management. DATA SELECTION: Twenty-five references were identified. DATA EXTRACTION: References were reviewed by a multidisciplinary team and graded according to the following criteria: randomized controlled trial; controlled trial, no randomization; observational study; and expert opinion. Evidence tables were developed for each focus question. DATA SYNTHESIS: An algorithm and clinical care guideline were developed by consultation and consensus among team members. Emphasis was placed on methods to promote early identification of pediatric idiopathic constipation and soiling, to recognize points of referral, and to increase patient and family compliance with treatment through use of education, developmentally based interventions, and variables for tracking success of management. CONCLUSION: An algorithm and guideline for pediatric idiopathic constipation and soiling are presented for use by primary care physicians.

Child↗

PubMed1998

Improving vision: neural compensation for optical defocus.

Anecdotal reports abound of vision improving in myopia after a period of time without refractive correction. We explored whether this effect is due to an increased tolerance of blur or whether it reflects a genuine improvement in vision. Our results clearly demonstrated a marked improvement in the ability to detect and recognize letters following prolonged exposure to optical defocus. We ensured that ophthalmic change did not occur, and thus the phenomenon must be due to a neural compensation for the defocus condition. A second set of experiments measured contrast sensitivity and found a decrease in sensitivity to mid-range (5-25 cycles deg-1) spatial frequencies following exposure to optical defocus. The results of the two experiments may be explained by the unmasking of low contrast, high spatial frequency information via a two-stage process: (1) the pattern of relative channel outputs is maintained during optical defocus by the depression of mid-range spatial frequency channels; (2) channel outputs are pooled prior to the production of the final percept. The second set of experiments also provided some evidence of inter-ocular transfer, indicating that the adaptation process is occurring at binocular sites in the cortex.

Adaptation, Physiological↗

PubMed1996

Effect of chronic continuous positive airway pressure (CPAP) therapy on upper airway size in patients with sleep apnoea/hypopnoea syndrome.

BACKGROUND: There is evidence to suggest that chronic continuous positive airway pressure (CPAP) therapy may produce reversible changes in upper airway morphology and function in patients with sleep apnoea/hypopnoea. This study was designed to examine the effect of chronic CPAP therapy on upper airway calibre. METHODS: Twenty four men with the sleep apnoea/hypopnoea syndrome (mean (SE) apnoea/hypopnoea index 37 (5)) underwent lateral cephalometry with measurement of posterior airway space performed before and at least three months after initiation of CPAP therapy. RESULTS: There was no weight change between the two assessments and mean CPAP use was 4.8 (0.4) hours per night. Posterior airway space (PAS) was measured in erect and supine postures. PAS supine increased with CPAP therapy from a mean (SE) of 11.8 (0.8) mm to 13.4 (0.8) mm, but PAS erect did not. Correlation of the change in PAS (dPAS) before and after CPAP therapy showed an increase with increasing CPAP compliance measured as machine run time both for dPAS supine (r = 0.68) and dPAS erect (r = 0.47). CONCLUSIONS: Patients with the sleep apnoea/hypopnoea syndrome regularly using CPAP for more than four hours per night all showed an increase in dPAS supine. The use of chronic CPAP increases PAS supine probably by a reduction in upper airway oedema, and the change in size is dependent on CPAP use.

Cephalometry↗