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Biomedical subjects

Zhaoping Li

Publications and source records attributed to Zhaoping Li.

6 recordsLinked to original sources
PubMed2003

Characteristics of bariatric surgery in an integrated VA Health Care System: follow-up and outcomes.

BACKGROUND: Since the 1991 NIH consensus conference, obesity surgery has been increasingly accepted as a form of therapy for morbid obesity. Approximately 40% of Veteran patients are obese and would potentially benefit from the operations. METHODS: Records were reviewed for all obesity operations performed at the Veterans Administration Greater Los Angeles Health Care System between January 1997 and April 2002. Morbidity, mortality, weight loss, and extent of follow-up were the outcomes measures assessed. RESULTS: Forty-six [11 Female (24%), 35 Male (76%)] patients underwent Roux-Y gastric bypass during the 63-month period we reviewed. There was one death from pulmonary hypertension unexpectedly encountered in the operating room. There was a single major complication: an anastomotic leak successfully treated with intravenous antibiotics. The Computerized Patient Record System contained extensive weight loss information, with dozens of weight measurements for these patients before and after surgery. Weight loss was sustained in all but 2 patients during the follow-up period. The only patients lost to follow-up were those referred from medical centers outside the boundaries of our integrated health care system. CONCLUSION: (1) The VA population has the opposite male/female ratio of populations reported in most weight loss studies. Because the health risks attributable to obesity are greater in males, the VA represents an important population to study that may benefit significantly from weight loss surgery. (2) Extensive clinical information available in the computerized medical record combined with frequent accession of health care resources by our patients resulted in a database rich in follow-up data for a population where long-term outcomes are traditionally difficult to obtain. (3) There was very low surgical morbidity and mortality in a high-risk population. This contrasts with the results of most volume-outcome studies and occurred in a low-volume hospital by a high-volume surgical and medical team. (4) Distinct patterns of weight loss were observed.

Delivery of Health Care, Integrated↗
PubMed2002

Subthalamic-pallidal interactions are critical in determining normal and abnormal functioning of the basal ganglia.

The subthalamic nucleus (STN) and external globus pallidus (GP) form a recurrent excitatory-inhibitory interaction within the basal ganglia. Through a computational model of these interactions we show that, under the influence of appropriate external input, the two nuclei can be switched between states of high and low activity or can generate oscillations consisting of bursts of high-frequency activity repeated at a low rate. It is further demonstrated from the model that the generation of the repetitive bursting behaviour is favoured by increased inhibition of the GP, which is a condition indicated in Parkinson's disease. Paradoxically, increased striatal inhibition of the GP is predicted to cause an increase rather than a decrease in its mean firing rate. These behaviours, arising from a biologically inspired computational model of the STN-GP interaction, have important consequences for basal ganglia function and dysfunction.

Basal Ganglia↗
PubMed2002

A saliency map in primary visual cortex.

I propose that pre-attentive computational mechanisms in primary visual cortex create a saliency map. This map awards higher responses to more salient image locations; these responses are those of conventional V1 cells tuned to input features, such as orientation and color. Hence no separate feature maps, or any subsequent combination of them, is needed to create a saliency map. I use a model to show that this saliency map accounts for the way that the relative difficulties of visual search tasks depend on the features and spatial configurations of targets and distractors. This proposal links psychophysical behavior to V1 physiology and anatomy, and thereby makes testable predictions.

Journal Article↗
PubMed2002

Vitamin A deficiency in a newborn resulting from maternal hypovitaminosis A after biliopancreatic diversion for the treatment of morbid obesity.

BACKGROUND: Biliopancreatic diversion (BPD) has been advocated for the treatment of morbid obesity. This procedure has the theoretical advantage that patients retain normal eating capacity and lose weight irrespective of their eating habits. However, vitamin deficiencies may develop because BPD causes malabsorption. OBJECTIVE: This report describes a 40-y-old mother and her newborn infant, who developed vitamin A deficiency as a result of iatrogenic maternal malabsorption after BPD. Our primary objective is to show that BPD patients need close follow-up and lifelong micronutrient supplementation to prevent nutrient deficiencies in themselves and their offspring. DESIGN: The medical records of the mother and infant were reviewed, and their clinical course was followed until 10 mo postpartum. The mother was also interviewed on several occasions about her medical care, follow-up, and supplemental vitamin use. RESULTS: The mother developed night blindness with undetectable serum vitamin A concentrations in the third trimester of her pregnancy. Her vitamin A deficiency was untreated until she delivered her infant. At delivery, the infant also had vitamin A deficiency. He may have permanent retinal damage, but this is still unclear because the ophthalmologic examination performed at 2 mo of age was inconclusive. CONCLUSIONS: Complications of BPD may take many years to develop, and the signs and symptoms may be subtle. Because of the malabsorption that results from BPD, patients need lifelong follow-up and appropriate vitamin supplementation to prevent deficiencies. These nutrient deficiencies can also affect the offspring of female BPD patients.

Adult↗
PubMedDate not supplied

Safety and efficacy of postoperative continuous positive airway pressure to prevent pulmonary complications after Roux-en-Y gastric bypass.

Continuous positive airway pressure (CPAP) is used to prevent apneic arrest and/or hypoxia in patients suffering from obstructive sleep apnea. This modality has not been universally accepted for patients following upper gastrointestinal surgery because of concerns that pressurized air will inflate the stomach and proximal intestine, resulting in anastomotic disruption. This study was performed to assess the safety and efficacy of postoperative CPAP for patients undergoing a gastrojejunostomy as part of a Roux-en-Y gastric bypass (RYGB) procedure. A total of 1067 patients (837 women [78%] and 230 men [22%]) were prospectively evaluated for the risk of developing anastomotic leaks and pulmonary complications after the RYGB procedure. Of the 1067 patients undergoing gastric bypass, 420 had obstructive sleep apnea and 159 were dependent on CPAP. There were 15 major anastomotic leaks, two of which occurred in CPAP-treated patients. Contingency table analysis demonstrated that there was no correlation between CPAP utilization and the incidence of major anastomotic leakage (P = 0.6). Notably, no episodes of pneumonia were diagnosed in either group. Despite the theoretical risk of anastomotic injury from pressurized air delivered by CPAP, no anastomotic leaks occurred that were attributable to CPAP. There were no pulmonary complications in a patient population that is at risk for developing them postoperatively. CPAP is a useful modality for treating hypoventilation after RYGB without increasing the risk of developing postoperative anastomotic leaks.

Adult↗