Theophylline pharmacokinetics in normal elderly subjects.

The effect of age on theophylline kinetics was examined in six normal young men and six elderly men. There were no age-associated differences in theophylline volume of distribution, total clearance, or t1/2. The unbound fraction of theophylline was significantly raised in the elderly (mean 77.7% vs. 62.3%, p less than 0.001) and was correlated with the serum albumin level (r = -0.7, p less than 0.01). Theophylline nonrenal clearance was not changed, but the total unbound clearance was significantly reduced in the elderly subjects as compared with the young ones (mean 0.744 vs. 1.085 ml/min/kg, p less than 0.05). Creatinine clearance was reduced in the elderly and was significantly correlated with unbound renal clearance (r = 0.6, p less than 0.04). There were no age-related differences in the urinary excretion of theophylline, 1-methyluric acid, 3-methylxanthine, or 1,3-dimethyluric acid. However, significant reduction in unbound renal theophylline clearance (p less than 0.002) as well as the unbound metabolic clearance of 1,3-dimethyluric acid (p less than 0.03), 3-methylxanthine (p less than 0.04), and 1-methyluric acid (p less than 0.02) were observed in the elderly subjects. These observations indicate that both renal and metabolic elimination processes for theophylline are less active in the normal elderly.

Dengue shock syndrome in an American traveler with primary dengue 3 infection.

A previously reported case of childhood dengue shock syndrome in an American traveler to India was investigated serologically. The original studies neither indicated the infecting serotype nor proved primary or secondary infection. However, BHK suspension PRNT of 6-year convalescent serum now indicates that the child had primary dengue type 3 infection. Dengue, dengue hemorrhagic fever, and dengue shock syndrome are potential hazards for American travelers and American residents of dengue-receptive areas.

Hypophagia among hospitalized elderly.

A prospective study was done in 21 hospitalized medical patients to determine the effects of age and gender on food intake. From precise weighing of food served and uneaten, macronutrients and micronutrients ingested during the hospital stay were determined. Even though the hospital diet served was adequate in energy and protein, 38% of the patients ingested less than 65% of their nutritional requirements, with a higher percentage of those with inadequate intake among the elderly than among the young (28% vs. 10%). Patients over 65 years of age ingested less energy and protein than those under 65 years of age (1,167 vs. 1,967 kcal, p less than .01; 47 vs. 78 gm, p less than .05). The gender of the patients had no influence on food intake. More than 60% of the medical patients, especially the elderly, had an inadequate intake of micronutrients: folate, 100% of the elderly vs. 93% of the young; zinc, 90% vs. 64%; magnesium, 90% vs. 36%; and vitamin B-6, 90% vs. 64%. Multiple stepwise regression analysis showed that age and body weight on admission were of predictive value in terms of subsequent nutrient intakes during the hospitalization. Patients who were over 65 years old and weighted less than 80% of their ideal body weight consumed significantly less energy and fewer macronutrients and micronutrients.

Total correction of tetralogy of Fallot in adults--surgical experience.

A total of 100 patients of tetralogy of Fallot aged 13 years and over were operated upon at the All India Institute of Medical Sciences, New Delhi, India between January 1991 and December 1996. There were 69 males (69%) and 31 females (31%). Age ranged from 13 years to 43 years (mean 19.66 years). Twenty % of patients had preoperative complications like haemoptysis, cerebrovascular accidents, brain abscess and infective endocarditis. Twenty-two patients had previous palliative shunts. Fifteen patients had coil embolisation of major collaterals prior to surgery. In hospital mortality rate was 4%. Follow-up ranged from 1 month to 5 years (mean 3.4 years). There was one late death due to infective endocarditis. Postoperatively 93.6% patients were in NYHA class I. Significant residual defects warranting re-operation were present in three patients. Total correction of tetralogy of Fallot in older patients can be performed with acceptable results.

Management of annuloaortic ectasia in association with aortic regurgitation.

Annuloaortic ectasia associated with severe aortic regurgitation is usually managed by implanting a composite graft that comprises both valve and conduit. Synthetic valved conduits have been used by most cardiovascular surgeons, with various modifications in the technique. Yet prosthetic valves carry the risks associated with anticoagulation therapy, together with an increased risk of infective endocarditis. We report a case in which a cryopreserved aortic homograft was used for a Bentall procedure in a patient who had annuloaortic ectasia with severe aortic regurgitation. To the best of our knowledge, there are no prior published reports of homograft insertion in treatment of annuloaortic ectasia.

Nasolacrimal duct obstruction caused by an oncocytoma.

We report the case of a woman with epiphora and purulent rhinorrhea for which she initially underwent a dacryocystorhinostomy. The unilateral rhinorrhea was persistent and one year later an oncocytoma of the lacrimal sac with extension to the nasolacrimal duct was diagnosed. Surgical excision of the tumour via a medial maxillectomy was accomplished. Long-term follow-up for 10 years was without evidence of recurrence. To our knowledge only 22 oncocytomas of the lacrimal sac but none involving the duct have so far been reported. In patients with acquired nasolacrimal duct obstruction a lacrimal sac or nasolacrimal duct tumour though rare is a possibility and should be kept in mind. The majority of these tumours are malignant and oncocytomas may undergo malignant transformation.

Routine cleft closure in repair of complete atrioventricular septal defects.

Thirty patients with complete atrioventricular septal defect were operated upon between 1989 and 1996 at our institute. Their ages ranged from two months to 24 years (mean age 2.81 years). All patients had severe pulmonary arterial hypertension except one who had associated pulmonic stenosis. Four patients had severe atrioventricular valve regurgitation and another six had moderate regurgitation. Five patients had Down's syndrome. The cleft in the left atrioventricular valve was closed in all but seven patients. There were five (16.66%) in-hospital deaths which included two patients in whom the cleft was left open. Follow-up ranged from three months to eight years. All patients were evaluated by 2D echocardiography in the immediate post-operative period and three to six monthly subsequently. One patient progressed to moderate and another to severe left atrioventricular valve regurgitation during follow-up. In both the patients the cleft had been left open. All other patients continue to have stable left atrioventricular valve status, that is, none or trivial to mild regurgitation. In view of late deterioration of the left atrioventricular valve regurgitation only in those patients where the cleft was left open, we suggest complete closure of the cleft in all complete atrioventricular canal defects.

Effects of a low calorie, low protein diet on nutritional parameters, and routine laboratory values in nonobese young and elderly subjects.

The effect of a low calorie (1100 kcal), low protein (35 g) intake for 9 days on nutritional and laboratory parameters was studied in six young and six elderly healthy subjects. All subjects lost weight on the test diet (an average of 2.0 kg in the young and 2.1 kg in the elderly). Basal serum albumin, serum transferrin, creatinine height index, and creatinine clearance in the elderly subjects were lower than in the young (p less than 0.05). Serum albumin remained unchanged at the end of diet in both groups. There was, however, a significant decrease in the transferrin level in the younger subjects (p less than 0.01). The decrease in creatinine height index was not significant in either group. Baseline nitrogen balance of the elderly was -1.1 g/day compared to +0.5 g/day (p less than 0.01) in the young subjects. The test diet caused a negative nitrogen balance of about -5 g/day in both groups (p less than 0.005). Blood urea nitrogen was significantly lower at the end of the test diet and was related to the intake of protein in both groups. At the end of the diet the serum potassium and GGT were significantly lower in the young (p less than 0.01); serum creatinine was unchanged but creatinine clearance was significantly lower in both groups. From this study it appears that significant changes occur in nutritional and laboratory parameters within 9 days on a diet deficient in calories and protein in normal healthy subjects. These changes need to be recognized as having nutritional basis and should not be attributed to illness or drug therapy.

Response to head-up tilt in cramping and noncramping hemodialysis patients.

Hemodialysis-associated skeletal muscle cramps are generally ascribed to a reduction in plasma volume, but during this procedure, it is not known how volume contraction results in cramps. To elucidate this mechanism, we compared responses to one hour of 60 degrees head-up tilt in 8 patients who cramped during no more than one-sixth of their dialyses and in 8 patients who cramped at least half the time. Age and recumbent blood pressure were similar in each group, but more patients with frequent cramps had diabetes underlying their renal failure (p = 0.013) and had been dialyzed for less than 3 years (p = 0.020). Baseline plasma renin activity and plasma norepinephrine and arginine vasopressin concentrations were similar in both groups, except plasma renin activity in one patient with frequent cramps, which was 15 times higher than in the other patients. After tilting, systolic blood pressure fell an average of 17% in patients who cramped infrequently (p = 0.0031) but only 10% in frequently cramping patients. The ratio of tilt/recumbent norepinephrine levels exceeded 1.5 in 7 patients with frequent cramps but was less than this in 6 patients who cramped infrequently (p = 0.020). One of the 2 infrequently cramping patients with a ratio above 1.5 was the only individual to have a normal renin response to tilt. We propose that cramps are prone to occur during hemodialysis in patients whose sympathetic nervous system response to volume stress is partially intact but is not modulated by concurrent activation of the renin-angiotensin system.