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Biomedical subjects

P Hari

Publications and source records attributed to P Hari.

At least 19 recordsLinked to original sources
PubMed2006

Cure of multiple myeloma -- more hype, less reality.

Randomized studies have firmly established the role of autologous transplant as initial therapy in multiple myeloma (MM). Indeed, MM has emerged as the commonest indication for autologous SCT in North America. The conceptual basis for high-dose therapy is the goal of complete remission (CR) through steep reduction in tumor burden affected by single and tandem transplants. Careful analysis of the data challenges the notion of CR as a surrogate to success. Intrinsically aggressive MM, defined by known unfavorable biologic risk factors, overrides the benefit of CR. In contrast, subgroups of patients with favorable biological risk factors may achieve prolonged survival, often without ever achieving CR. Unfortunately, even with tandem transplants, there is no plateau in survival curves. To this end, sequential autologous followed by nonmyeloablative allotransplants are a novel attempt at 'curing' myeloma, but the results thus far have failed to show a definite plateau in survival. Given the improvements in supportive care and concomitant reduction in transplant-related mortality, conventional myeloablative allogeneic transplants need to be re-examined as an option in high-risk aggressive myeloma. At the same time, novel antimyeloma therapies, newer risk stratification and staging tools are transforming the treatment algorithm. We examine the changing role of transplantation in myeloma in the context of novel drug therapy, biologic risk stratification and improving supportive care while arguing that the current 'one size fits all' transplant approaches are far from a cure.

Disease-Free Survival↗
PubMed2001

Treatment of focal glomerulosclerosis with pulse steroids and oral cyclophosphamide.

Patients with steroid-resistant nephrotic syndrome often have an unsatisfactory long-term outcome and are at risk of developing chronic renal failure. We prospectively treated 65 children with idiopathic steroid-resistant nephrotic syndrome and focal segmental glomerulosclerosis (FSGS) with intravenous pulses of corticosteroids and oral cyclophosphamide. Dexamethasone (5 mg/kg) or methylprednisolone (30 mg/kg) was administered intravenously, initially 6 pulses on alternate days, followed by 4 fortnightly and 8 monthly pulses. Oral cyclophosphamide therapy was given for 12 weeks and tapering doses of prednisolone were administered for 52 weeks. The mean age at treatment was 85.7+/- 44.9 months. Five patients developed serious infections during administration of initial alternate-day pulses and were excluded. Of 59 patients who completed initial alternate-day therapy, 17 had complete and 8 partial remission; 34 (57.6%) patients did not respond to treatment. The median urine protein to creatinine ratio decreased from 10.0 to 0.75 (P<0.005) and serum albumin increased from 1.9 g/dl to 2.4 g/dl (P<0.01). The median duration of follow-up after stopping pulse therapy was 25.6 months. Thirty-four patients were followed for more than 3 years (median 4.5 years). Of these, 22 (64.7%) patients had a favorable outcome; persistent complete remission was seen in 15 patients and steroid-responsive relapses in 7. Seven patients had non- nephrotic-range proteinuria, 2 had nephrotic-range proteinuria, and 3 (8.8%) were in chronic renal failure. There was no significant difference in the short- and long-term outcome of patients with initial (n=28) and late resistance (n=31). The outcome in patients receiving intravenous dexamethasone (n=48) or methylprednisolone (n=11) was also similar. The chief side effects included worsening of height standard deviation score (47.4%), transient hypertension (42.5%), and serious infections (18.5%). We conclude that prolonged treatment with intravenous corticosteroids and oral cyclophosphamide is beneficial in patients with steroid-resistant FSGS. Expensive protocols can be successfully modified and used, depending upon the availability of health resources.

Administration, Oral↗
PubMed2001

Tree stem diameter variations and transpiration in Scots pine: an analysis using a dynamic sap flow model.

A dynamic model for simulating water flow in a Scots pine (Pinus sylvestris L.) tree was developed. The model is based on the cohesion theory and the assumption that fluctuating water tension driven by transpiration, together with the elasticity of wood tissue, causes variations in the diameter of a tree stem and branches. The change in xylem diameter can be linked to water tension in accordance with Hookeâ s law. The model was tested against field measurements of the diurnal xylem diameter change at different heights in a 37-year-old Scots pine at Hyytiälä, southern Finland (61 degrees 51' N, 24 degrees 17' E, 181 m a.s.l.). Shoot transpiration and soil water potential were input data for the model. The biomechanical and hydraulic properties of wood and fine root hydraulic conductance were estimated from simulated and measured stem diameter changes during the course of 1 day. The estimated parameters attained values similar to literature values. The ratios of estimated parameters to literature values ranged from 0.5 to 0.9. The model predictions (stem diameters at several heights) were in close agreement with the measurements for a period of 6 days. The time lag between changes in transpiration rate and in sap flow rate at the base of the tree was about half an hour. The analysis showed that 40% of the resistance between the soil and the top of the tree was located in the rhizosphere. Modeling the water tension gradient and consequent woody diameter changes offer a convenient means of studying the link between wood hydraulic conductivity and control of transpiration.

Models, Biological↗
PubMed2000

Phrenic nerve palsy: a rare complication of indwelling subclavian vein catheter.

The use of central venous catheters as access for hemodialysis has become common in children with end-stage renal disease. Phrenic nerve palsy is an unusual complication of this procedure. We report a case of delayed right diaphragmatic palsy due to phrenic nerve damage resulting from an indwelling right subclavian catheter in a 3-year-old child.

Catheters, Indwelling↗
PubMed2000

Sustained hypertension in children.

OBJECTIVE: To study the etiology and clinical profile of children with sustained hypertension. DESIGN: Retrospective hospital-based study. SETTING: Tertiary care, referral center. SUBJECTS: 246 children with sustained hypertension presenting between January 1983 and December 1996. RESULTS: The mean age at presentation was 8.2+/-3.9 yr; range 2 months-16 yr. There were 180 boys. An underlying cause for hypertension was identified in 242 (98.4%); 4 patients were considered to have essential hypertension. The chief causes included chronic glomerulonephritis (GN) in 121 (49.2%), obstructive uropathy in 39 (15.8%), reflux nephropathy in 30 (12.2%), thrombotic microangiopathy in 15 (6.1%) and renovascular disease in 14 (5.7%). Takayasu's disease was the most common cause of renovascular hypertension. Coarctation of aorta was the commonest cause of hypertension in infancy, being present in 53.3% of cases. In 198 subjects (80.5%) hypertension was detected as a feature of a known underlying disease. Thirty-five patients however, presented for the first time with complications of severe hypertension, including congestive cardiac failure in 21 and encephalopathy in 23. Thirteen patients presented with nonspecific symptoms and hypertension was detected on clinical examination. CONCLUSIONS: Most patients with sustained hypertension have an underlying etiology. A significant proportion of patients with renovascular and endocrine conditions may present, for the first time, with complications of hypertension.

Adolescent↗
PubMed1999

A three-dimensional stomatal CO2 exchange model including gaseous phase and leaf mesophyll separated by irregular interface

A three-dimensional model was constructed for studying the diffusion of CO2 molecules from air into stomatal air spaces and further into leaf mesophyll cells. The model covers two different phases, mesophyll and air, with appropriate boundary conditions. Sinks for CO2 molecules were obtained from a well-known biochemical photosynthesis model parametrized for Scots pine. The effects of the varying stomatal geometry on the CO2 flux and intercellular-air-space (IAS) and mesophyll concentrations were examined. The net CO2 flux is sensitive to the size of the IAS-mesophyll interface when the mesophyll transport coefficient is low, equalling the diffusivity of CO2 in water. The simulations have revealed an optimum between the volume of the assimilating mesophyll and the air-mesophyll interface. The solubility of CO2 molecules into water in the cell surfaces, which depends on temperature and pH, had a clear effect on the flux. Increasing pH from the value indicated by the physical solubility (pH reverse similar6) leads to an increase in the temperature maximum for CO2 flux into higher temperatures and to unrealistically high CO2 concentrates in the mesophyll. Copyright 1999 Academic Press

Journal Article↗
PubMed1999

Prolonged versus standard prednisolone therapy for initial episode of nephrotic syndrome.

We have examined, in a prospective randomized controlled trial, the effect of 8- and 16-week initial steroid treatment on the course of idiopathic nephrotic syndrome (INS). Patients with a first episode of INS were randomized to receive standard 8-week prednisolone (2 mg/kg daily for 4 weeks, then 1.5 mg/kg on alternate days for 4 weeks) or prolonged 16-week prednisolone treatment (2 and 1.5 mg/kg daily each for 4 weeks, then 1.5 and 1 mg/kg on alternate days each for 4 weeks). Relapses were treated with prednisolone, 2 mg/kg daily for 2 weeks, then 1.5 mg/kg on alternate days for 4 weeks. Of 45 patients, 23 received standard therapy and 22 prolonged therapy. The mean duration of follow-up was 29.2 and 27.3 months in the standard and prolonged treatment groups, respectively. The time to first relapse was longer in the prolonged treatment (mean 222.2 days, median 120.0 days) than the standard group (mean 134.3 days, median 96.5 days). The percentage of patients with no relapse at 6 and 12 months after prednisolone withdrawal was 40.9% and 27.3% in the prolonged treatment and 21.7% and 8.7% in the standard groups, respectively. The inability to show statistically significant differences between the two groups was probably related to the small number of patients studied. Prolonged therapy did not affect the subsequent relapse rates and proportion of patients with frequent relapses and steroid dependence. The mean dose of prednisolone received, for the initial episode and relapses during the next year, was higher and associated with significant steroid toxicity in the prolonged treatment group. Our findings suggest that 16-week prednisolone treatment for the initial episode of INS may delay occurrence of the first relapse, but results in significant side effects. Prolongation of initial therapy may be useful in developing countries where frequent infections often induce early relapses.

Child↗
PubMed1997

Neonatal renal failure due to obstructive candidal bezoars.

Acute renal failure (ARF) developed in a 7-week-old infant due to bilateral candidal bezoars (fungal balls) causing obstruction at the pelviureteric junction. The baby was born at term with an appropriate birthweight, and had been treated with broad-spectrum antibiotics for respiratory distress and septicemia during the 1st week of life. Recovery from ARF followed renal decompression with bilateral nephrostomy tube placement and parenteral administration of amphotericin B and 5-flucytosine.

Acute Kidney Injury↗
PubMed1996

Improving the reliability of a combined phenological time series by analyzing observation quality.

Collecting phenological data is a slow process. Although such data have been collected by a number of organizations, the reliability of these data is not known because the data-generating process cannot be repeated. No further observations to improve the reliability can be obtained. However, the data usually consist of several overlapping observation series and this overlap can be utilized to construct a combined phenological time series and to improve its reliability. We have developed two techniques for selecting the most reliable observations or observation series and thereby improve the reliability of the combined time series. Both techniques require that the method used to combine the separate phenological time series adjusts the individual series to eliminate possible systematic differences between them. A data set of bud burst in Betula pendula Roth collected in Central Finland during 1896-1955 was adjusted and used to test both techiques. Both techniques considerably improved the reliability of the combined time series; the mean of the confidence intervals of the annual means decreased by 12%. Despite the improvement in reliability, the resulting changes in the annual values of the combined time series were small, the largest change being 2.5 days. Removing outliers was the most effective method of improving reliability, i.e., it resulted in the greatest improvement with the smallest number of discarded observations.

Journal Article↗
PubMed1995

Aetiology of nephrolithiasis in north Indian children.

The aetiology of nephrolithiasis was investigated in 32 north Indian children (25 boys, 7 girls, mean age 7.9 +/- 3.3 years). An underlying disorder was detected in 16 (50%) patients and included idiopathic hypercalciuria (8 patients), hyperoxaluria (3 patients) and renal tubular acidosis, primary hyperparathyroidism and hyperuricosuria (1 patient each). Magnesium ammonium phosphate calculi were found in 2 patients with recurrent urinary tract infections, 1 of whom had a duplex pelvic collecting system. In 16 patients (50%) a cause for renal calculi was not identified. Our findings suggest that an underlying disorder is present in a large proportion of children with nephrolithiasis where appropriate treatment may be beneficial.

Calcium↗