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Biomedical subjects

A Spitzer

Publications and source records attributed to A Spitzer.

At least 127 records · Page 7Linked to original sources
PubMed1976

A simple estimate of glomerular filtration rate in children derived from body length and plasma creatinine.

Based on statistical analysis of data in 186 children, a formula was derived which allows accurate estimation of glomerular filtration rate (GFR) from plasma creatinine and body lenght (GFR(ml/min/1.73 sq m) = 0.55 length (cm)/Per (mg/dl). Its application to clearance data in a separate group of 223 children reveals excellent agreement with GFR estimated by the Ccr (r = .935) or Cin (r = .905). This formula should be useful for adjusting dosages of drugs excreted by the kidney and detecting significant changes in renal function.

Adolescent↗
PubMed1976

Effect of chronic salt and water loading on the tubular defects of a child with Fanconi syndrome (cystinosis).

A male child discovered to have cystinosis and Fanconi syndrome at the age of 2 years 8 months was hospitalized repeatedly for episodes of hyponatremic, hypokalemic dehydration and acidosis. Attempts to correct the fluid and electrolyte abnormalities by increasing progressively the supplements of sodium chloride, sodium bicarbonate, and potassium chloride resulted only in an exacerbation of the symptoms. Tests of discrete renal functions and metabolic balance studies disclosed that, although all disturbances were expressions of the primary disease, their severity was enhanced considerably by the extracellular volume expansion induced by the vigorous therapy. Restriction in water intake resulted in an improvement in the renal performance and in the clinical condition.

Absorption↗
PubMed1975

Late nonresponsiveness to steroids in children with the nephrotic syndrome.

Among 195 nephrotic children, ten developed resistance to prednisone therapy after responding to this drug on one or more occasions (late nonresponders). All were found to have "minimal lesions" on renal biopsy. Nine of these patients went into remission: one responded to further prednisone therapy, one went into remission while receiving azathioprine, and the remaining seven children responded to cyclophosphamide. Five of these seven patients subsequently relapsed; three of them have continued to respond to prednisone. The other two eventually became steroid resistant a second time, but in both instances a second course of cyclophosphamide again induced a remission. These nine patients have been followed for periods ranging from 6 months to 9.5 years (median = 53 months); all are doing well and have normal renal function. The tenth patient died from sepsis four months after the onset of steroid resistance.

Azathioprine↗
PubMed1975

Neonatal changes in renal blood flow distribution in puppies.

The intrarenal distribution of blood flow was studied in 31 newborn mongrel puppies from 18 h to 70 days using xenon washout and krypton autoradiography. Mean renal blood flow increased from 0.39 plus or minus 0.05 ml/g per min (SE) the 1st wk to 2.06 plus or minus 0.12 ml/g per min at 6 wk. During the 1st wk of life renal cortex was perfused homo-geneously at 0.88 plus or minus 0.19 ml/g per min (SE) and accounted for 35 plus or minus 4% of the renal blood flow. During the 2nd wk a narrow, rapidly perfused zone of outer cortex was identified which was perfused at 3.35 plus or minus 0.26 ml/g per min, received 19.53 plus or minus 5.05% of the total renal blood flow, and represented 15 plus or minus 4% of the mass of the total cortex. The inner cortex and outer medulla at this time received 53.40 plus or minus 4.12% of the flow at 1.07 plus or minus 0.08 ml/g per min. Outer cortical flow increased with age reaching adult values by about 6-10 wk when the rapidly perfused area represented 40 plus or minus 8% of the cortex. These changes are parallel to the results of previously reported studies with microspheres in newborn puppies and are compatible with the well established maturational changes noted in neonates of several species. They represent the first gas-washout studies in animals during the first 6 wk of life.

Age Factors↗
PubMed1975

Recurrent hemolytic-uremic syndrome: a case report.

A girl who developed HUS at 2 years of age had four further episodes of the disease during the next 2 1/2 years. No renal or hematologic abnormalities were detected during or between the attacks. Reduced levels of serum complement were found during three of the episodes.

Child, Preschool↗
PubMed1974

Functional and morphologic maturation of the superficial nephrons. Relationship to total kidney function.

The functional and morphologic pattern of superficial nephron development was studied in guinea pigs ranging in age between 2 h and 38 days. Concomitent measurements of total kidney function and glomerular counts were also performed. Superficial nephron glomerular filtration rate was found to increase from 0.92 to 19.32 nl/min. The filtration rate of the entire kidney rose from 0.19 to 1.31 ml/min. During the first 15 days of life the average rate of increase in glomerular filtration rate per nephron (0.48 nl/min.day), obtained by dividing the increase in total kidney glomerular filtration rate by glomerular number, was more than twice the observed rate of increase in the superficial nephrons (0.21 nl/min.day). During the remainder of the first month, the increase in superficial nephron glomerular filtration rate (0.97 nl/min.day) was greater than the average increase for all nephrons (0.71 nl/min.day). Thus, the initial increase in total kidney glomerular filtration rate was primarily a consequence of the activity of the deep nephrons, whereas during the ensuing period the superficial nephrons appeared to be the sole contributors to the change in total kidney glomerular filtration rate.The increase in superficial nephron glomerular filtration rate was found to correlate closely with the increase in proximal tubular length. Functional glomerulotubular balance was maintained throughout the entire period of renal maturation.

Aging↗
PubMed1973

Postnatal changes in renal glomerular blood flow distribution in puppies.

The intrarenal distribution of radionuclide microspheres injected into the thoracic aorta was used to examine glomerular blood flow distribution (GBFD) in 26 healthy, unanesthetized puppies, ranging in age from 5 h to 42 days, and in 5 adult dogs. For analysis, the cortex was divided into four equally thick zones designated zone I (subcapsular) to zone IV (juxtamedullary). During the first 36 h of life, the highest flow rate was in zone II, which received 35.5+/-2.0%/g, compared with 26.8+/-1.4% to zone I, 23.7+/-1.4% to zone III, and 13.4+/-1.4% to zone IV. At age 6 wk, zone I had the highest rate of perfusion (48.6+/-2.1%, compared with 28.8+/-1.4% in zone II, 15.8+/-0.8%, in zone III, and 6.8+/-0.6% in zone IV). The 6-wk old animals resembled the adult animals, except for relatively greater perfusion per gram of zone I in the former group. Changes in relative GBFD did not correlate with those in arterial pressure or peripheral hematocrit. The distribution of glomeruli among the four zones of the cortex followed its own pattern of development. At birth and at 6 wk, the greatest density of glomeruli was in zone I (50.6+/-5.4 and 42.7+/-3.9%/g respectively, as compared with 24.1+/-2.9% in adults); in adults zone II contained the greatest density (39.1+/-1.6%). At birth the relative perfusion of glomeruli in zone I was only one-fifth that of glomeruli in zone IV, with intermediate values in zones II and III. By 6 wk of age, increased perfusion of the outer cortical glomeruli resulted in rates of flow in the four zones that did not differ significantly from each other. Relative perfusion in zone I continued to increase, so that in the adult animals perfusion in that zone was significantly greater than in the three deeper zones. These data demonstrate the marked hemodynamic changes that take place within the kidney during the first few weeks of life. The relatively greater blood flow of the most deeply situated nephrons in the early postnatal period suggests ascendancy of this population of nephrons and may have important functional implications.

Age Factors↗