Biomedical subjects
D R Roy
Publications and source records attributed to D R Roy.
Femoral lengthening in patients having abnormal ipsilateral hip or knee.
Femoral lengthening using the Wagner technique was performed for 13 patients with abnormal adjacent joints. An average of 6.3 cm (19.5%) of lengthening was achieved. Three patients had no difficulties during lengthening. Transient non-surgical problems identified were blood pressure elevation, nerve palsy, and psychiatric reactions. Significant obstructions or complications occurred 13 times in nine cases. These included contractures of ipsilateral joints, angulations of the lengthened femur, Wagner device slippage, nonunion, and late hip subluxation. Other authors have reported similar difficulties in patients with normal ipsilateral joints. In this series, the advantage of achieving greater length appeared to outweigh the complications.
Dysplasia epiphysealis hemimelica. Upper limb involvement with associated osteochondroma.
Dysplasia epiphysealis hemimelica is a rare developmental disorder characterized by an osteocartilaginous outgrowth arising from 1 or more epiphyses. This condition is generally confined to the lower limb and usually involves either the medial or lateral side of an epiphysis. Reported here is an atypical case that involved the upper extremity and was associated with a typical metaphyseal osteochondroma in the same limb. The occurrence of histologically identical lesions at 2 different sites suggests that the lesions were different modes of expression of the same pathologic process.
Developmental dysplasia of the hip.
OBJECTIVE: The definition and early treatment of congenital dysplasia of the hip are controversial. The purpose of this study was to discuss the reasons for changing the acronym to developmental dysplasia of the hip (DDH) and to address its early detection and treatment. DESIGN: This multicenter study was designed to provide an updated assessment of the definition, pathologic anatomy, prevalence, etiology, natural history, early detection, and treatment of DDH. RESULTS: DDH more accurately describes the condition previously termed congenital dysplasia of the hip. The disorder is not always present at birth (congenital) and an infant may have a normal neonatal hip screening examination and subsequently develop a dysplastic or dislocated hip. Developmental dysplasia encompasses the wide spectrum of hip problems seen in infants and children. Physicians should understand that a normal neonatal screening examination does not assure normal hip development. The diagnosis of developmental dysplasia is made by physical examination. The Ortolani and Barlow maneuvers were designed to detect a subluxatable, dislocatable, or dislocated hip in the neonatal period. In the older child, limited abduction becomes a more reliable sign. The examination is variable depending on the type of dysplasia and changes with growth. The ultrasound is proving to be a sensitive tool in confirming the diagnosis in newborns and infants from birth to 4 months of age. The ultrasound is also valuable in older infants in terms of documenting that the dysplasia is responding to treatment. However, the ultrasound depends on an experienced sonographer and, in some cases, may be too sensitive, resulting in overtreatment. After 3 to 4 months of age, an anteroposterior pelvis radiograph can confirm the diagnosis. CONCLUSIONS: All newborns should have a neonatal hip screening physical examination. After screening, the hips should be re-examined during health examination visits at 2 weeks, 2 months, 4 months, 6 months, 9 months, and 1 year of age. If any question arises during these visits or if there are associated risk factors, we recommend an ultrasound if the infant is < 4 months of age or an anteroposterior pelvis radiograph if > 4 months of age.
Digital schwannoma in a skeletally immature child.
Soft tissue neoplasms of the hand are rare in general and even more uncommon in children. The most commonly considered diagnoses include ganglion, inclusion cyst, lipoma, subcutaneous foreign body granuloma, and tendon sheath xanthoma. Aside from pressure sensitivity, masses on the palmar aspect of the hand are often asymptomatic. The case reported here identifies a primary neural neoplasm (neurilemmoma) that involves a small peripheral nerve in the hand of a twelve-year-old child. The patient had no neurologic symptoms and illustrates the need to include neurilemmomas in the differential diagnosis of hand masses in children.
Perthes'-like changes caused by acquired hypothyroidism.
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Synthesis and characterization of extended and deleted recombinant analogues of parathyroid hormone-(1-84): correlation of peptide structure with function.
Recombinant analogues of human parathyroid hormone [hPTH-(1-84)] were expressed in Escherichia coli harboring plasmids containing synthetic genes under the control of the lac promoter. The level of expression of the gene encoding the truncated analogue, hPTH-(3-84), was greater than that of the gene encoding full-length hPTH-(1-84) but less than that of the gene encoding proparathyroid hormone (hProPTH). This may be due in part to the relative efficiency of translation of the mRNA as suggested by secondary structure analysis and in part because of enhanced stability of the extended peptide. Formylmethionyl derivatives of hProPTH and of hPTH-(3-84) and underivatized hPTH-(3-84) were purified by HPLC, and their identity was confirmed by NH2-terminal sequencing and amino acid analysis. The bioactivity of these recombinant peptides was then tested in skeletal and renal adenylate cyclase assays in vitro and in assays examining effects on plasma and urine calcium and phosphate levels and on urine cyclic AMP levels in vivo. The NH2-terminally extended analogue fMet-hProPTH displayed 10% of the in vitro activity of hPTH-(1-84) and was a partial agonist in vivo. The peptides hPTH-(3-84) and fMet-hPTH-(3-84) were inert in vitro and were very weak in vitro antagonists when compared to the NH2-terminal analogue bovine [Nle8,18Tyr34]PTH-(3-34)-NH2. In vivo, hPTH-(3-84) and the bPTH-(3-34) analogue, when assayed at a 10:1 molar ratio relative to bPTH-(1-84), were each inert, and neither demonstrated antagonist activity at these concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)
Operative management of fractures of the shaft of the radius and ulna.
Diaphyseal fractures of the radius and ulna usually can be managed by closed reduction and immobilization in a long arm cast. Open fractures may benefit from pinning if the reduction will be difficult to maintain. Fractures that cannot be reduced or for which satisfactory alignment maintained are best managed operatively. Our preference is for intramedullary fixation. Operative management will be necessary most frequently in children older than age 10.
Subtalar stabilization of the planovalgus foot by staple arthroereisis in young children who have neuromuscular problems.
A new approach was developed for the treatment of planovalgus feet in children who have spastic cerebral palsy and are less than six years old. The procedure consists of subtalar stabilization (arthroereisis) with a Vitallium staple, and it corrects alignment, restores balance, and allows continued function. It is safe, technically simple, and efficient. Between 1980 and 1988, forty-eight arthroereises were done. The results of thirty-one procedures in twenty patients who were two to ten years and ten months old at the time of the operation were followed for an average of 4.1 years (range, two to seven years). Approximately 85 per cent of the results were excellent or good. Only one foot needed a revision; this was due to migration of the staple. At the most recent follow-up, the talocalcaneal angle had not changed in about 50 per cent of the feet. In another seven, the change ranged from 5 to 10 degrees. All of these patients had a satisfactory result. In all but three feet, the goal of maintaining the stability of the talocalcaneal joint without orthotics or osseous fusion was achieved. Originally, the procedure was done only in patients who were less than six years old, but, because of its success, the indications were extended to children of any age who had severely involved and neurologically compromised feet. Satisfactory results were obtained in the older children as well.
Completely displaced distal radius fractures with intact ulnas in children.
Completely displaced distal radius fractures with intact ulnas are uncommon, difficult-to-reduce fractures in children. Ten of these fractures were retrospectively reviewed from a series of more than 600 forearm fractures. Eight of ten patients were available for follow up clinically and radiologically at an average of 21 months. Considerable remodeling was noted including two fractures that were left in an overriding position of 10 mm. If angulation does not exceed 16 degrees of radial deviation and 20 degrees of dorsal angulation, repeat manipulations need not be performed. Stimulation of growth by the fracture restored radial length. Thus, reduction of the overriding is unnecessary.
Influence of the amino-terminus on in vitro and in vivo biological activity of synthetic parathyroid hormone-like peptides of malignancy.
We compared the bioactivities of a synthetic truncated NH2-terminal fragment of the human (h) PTH-like peptide (PLP) associated with malignancies [hPLP-(3-34)], an intact NH2-terminal fragment [hPLP-(1-34)], and an NH2-terminal fragment of PTH [hPTH-(1-34)]. Although hPLP-(1-34) was less potent than hPTH-(1-34) in stimulating adenylate cyclase in rat renal membranes, hPLP-(1-34) and hPTH-(1-34) were equipotent in stimulating adenylate cyclase in OK renal cells as well as in UMR 108 osteosarcoma cells in vitro. In osteosarcoma cells, each of these peptides could desensitize adenylate cyclase responses to itself and to the other peptide, but could not reduce stimulation by prostaglandin E2. Renal membranes of vitamin D-deficient rats with secondary hyperparathyroidism had a reduced PLP-stimulated as well as PTH-stimulated adenylate cyclase response. The truncated analog hPLP-(3-34) was only a weak partial agonist and an antagonist in vitro, produced equivalent inhibition of hPLP-(1-34) and hPTH-(1-34) in renal and osseous cells, and could not desensitize agonist responses. In thyroparathyroidectomized rats in vivo, hPLP-(1-34) and hPTH-(1-34) increased cAMP excretion, enhanced phosphaturia, maintained plasma calcium, and reduced calciuria. Equimolar concentrations of hPLP-(3-34) produced no increases above control levels; however, high concentrations of this peptide mimicked PTH actions on renal and plasma ion handling while modestly augmenting cAMP excretion. These results demonstrate the importance of the first two residues of PLP for bioactivity, indicate that PLP and PTH interact at common receptor sites in vivo as well as in vitro, suggest that PLP may not be less potent than PTH in renal target cells, and indicate that the net result of interaction of these peptides with their common receptor in target tissues may reflect both activation and desensitization of receptor-mediated events.
Magnesium reabsorption in the juxtamedullary loop of Henle: effect of magnesium deprivation.
To determine the contribution of the juxtamedullary loop of Henle to magnesium reabsorption during magnesium deficiency, we performed two-phase micropuncture studies of end-descending limbs in a group of magnesium-deficient rats (n = 7) and in a pair-fed control group (n = 8) given MgCl2 in their drinking water. In the magnesium-deficient rats, daily excretion of magnesium fell to very low values (1.2 +/- 0.2 vs. 52 +/- 12 microM.day-1.100 g body weight-1, p less than 0.05). Plasma magnesium concentration and fractional magnesium excretion during the control phase were nearly 52 and 27%, respectively, of the values observed in pair-fed controls. Fractional magnesium delivery to the end-descending limb did not differ significantly between the two groups. During the acute magnesium repletion phase, fractional magnesium excretion and fractional magnesium delivery to the end-descending limb increased by a similar value in the two groups of rats, despite a lower filtered load of magnesium in the magnesium-deficient group. Absolute magnesium reabsorption upstream to the end-descending limb was lower in the magnesium-deficient rats but was otherwise tightly coupled to the filtered load of magnesium (Y = 0.91 + 0.37 x, r = 0.82, p less than 0.05). Similar observations were made with regards to whole kidney magnesium reabsorption. Our results suggest that, in young magnesium-deficient rats, magnesium reabsorption is tightly coupled to the filtered load of magnesium both in segments upstream to the juxtamedullary end-descending limb and in the whole kidney, and that a reabsorptive defect for magnesium is not evident in this setting.
Dyazide-induced reversible acute renal failure associated with intracellular crystal deposition.
Acute interstitial nephritis due to Dyazide therapy, ie, a combination of hydrochlorothiazide (25 mg) and triamterene (50 mg), has been recently reported in the literature. This had been characterized by nonoliguric renal failure after a long latent period (weeks) following exposure to the drug. Pathologic data have indicated a drug-induced hypersensitivity reaction. We report here one case of oliguric acute renal failure after a massive Dyazide intoxication. Based on the results of the renal biopsy and clinical course, we propose that the oliguria was secondary to a direct toxic effect on the tubules, and intrarenal obstruction was secondary to triamterene crystals and crystal-laden cells. In addition, pathologic findings also suggested a moderate hypersensitivity reaction. After hemodialysis and short-term steroid therapy, the patient achieved complete recovery of renal function within 12 days. Recent knowledge of triamterene-induced nephrolithiasis helps to explain the pathogenesis of acute renal failure in this patient, and is briefly reviewed here.
Acute effect of salmon calcitonin on renal magnesium transport in the magnesium-loaded rat.
The present studies were undertaken to examine whether salmon calcitonin, by increasing magnesium reabsorption in the thick ascending limb, and presumably the tubulointerstitial magnesium concentration gradient, would lead to an increase in fractional magnesium delivery to the end-descending limb (magnesium secretion) in magnesium-loaded rats. Thyroparathyroidectomized, postprandial Munich--Wistar rats were prepared for micropuncture of papillary end-descending limbs and of superficial end-accessible proximal tubules. Group 1 served as clonidine-water diuresis time controls; group 2 was treated as group 1 but also received synthetic salmon calcitonin (10 mU/min); and group 3 was treated as group 2 but also received calcium chloride intravenously. Calcitonin, alone or with calcium, produced a significant fall in fractional magnesium excretion. A significant relationship was also observed between fractional magnesium excretion and urine flow rate (r = 0.56, p less than 0.01). Calcitonin did not modify fractional magnesium delivery to the end-descending limb. A highly significant relationship was observed between tubule fluid-to-ultrafiltrate magnesium ratio and tubule fluid-to-plasma inulin ratio (r = 0.88, p less than 0.001). Within each group, fractional magnesium delivery to the end-descending limb was similar to the corresponding value in the superficial end-accessible proximal tubule. Our results suggest that despite intense magnesium reabsorption, presumably in the thick ascending limb, magnesium secretion does not occur in the juxtamedullary pars recta and (or) thin descending limb.
Effect of synthetic ANP on renal and loop of Henle functions in the young rat.
The present studies were undertaken to determine, by recollection micropuncture, the effect of a synthetic atrial natriuretic peptide (ANP) on the absolute and fractional deliveries of water and sodium to the juxtamedullary end-descending limb. Two groups of young female Munich-Wistar rats were studied: control (n = 8) received the vehicle only; and ANP (n = 12) received a prime followed by the constant infusion of a synthetic rat atrial peptide (28 amino acids). With the infusion of ANP, clearance of p-[14C]aminohippurate [( 14C]PAH) and glomerular filtration rate (GFR) fell significantly. Despite this fall in GFR and renal plasma flow, ANP produced a 2-fold increase in urine volume and a 10-fold increase in sodium excretion. Absolute and fractional sodium deliveries to the end-descending limb increased by approximately 30% in the ANP group, whereas mean juxtamedullary single-nephron glomerular filtration rate (SNGFR) remained stable. In three additional rats prepared for micropuncture of the superficial end-accessible proximal tubule, ANP reduced cortical SNGFR by approximately 15%. By contrast, GFR did not decline in response to ANP in larger rats, when treated identically. We conclude that in young rats ANP can produce a natriuresis in the absence of a rise in GFR; the fall in GFR observed following ANP is due presumably to the immaturity of the animals used in these studies; and ANP produces a rise in absolute and fractional water and sodium deliveries to the end-descending limb that cannot be attributed to a change in SNGFR.(ABSTRACT TRUNCATED AT 250 WORDS)
Purification of peptides with parathyroid hormone-like bioactivity from human and rat malignancies associated with hypercalcemia.
We have purified peptides with PTH-like bioactivity from a rat Leydig cell tumor (H-500) and a human squamous cell carcinoma, both associated with a syndrome of humor-induced hypercalcemia. Tumor extracts were shown to be active in an in vitro renal cytochemical bioassay and in an in vitro osteosarcoma cell (UMR 108) adenylate cyclase assay; activity in both assays could be reduced by the PTH antagonist [norleucine-8,18,tyrosine-34]bovine PTH-(3-34)-amide. Partially purified extracts of both tumors and of rat tumor-conditioned culture medium were active in vivo in thyroparathyroidectomized rats in preventing hypocalcemia and increasing fractional phosphorus excretion and cAMP excretion. Ion exchange chromatography demonstrated that active peptides were basic in character. Employing reverse phase HPLC and gel permeation HPLC, active peptides of approximately 9,000 and 9,500 daltons were purified from extracts of the human and rat tumors, respectively, which had similar but not identical compositions. Two additional bioactive peptides were detected in rat tumor extract, and the more active had a mol wt of approximately 28,000. The results demonstrate that peptides that mimic PTH in a variety of in vivo and in vitro bioassays can be extracted from malignancies associated with hypercalcemia, that multiple molecular species may be detected in tumors that demonstrate PTH-like activity, and that at least one of these peptides may be similar in two tumors of highly divergent cell and species origin.
Radioulnar synostosis following proximal radial fracture in child.
A case is presented with an eight-year follow-up of a proximal radial fracture complicated by radioulnar synostosis. The case and a review of the literature reveal that the complication is associated with certain risk factors. These factors include a fracture in a child over ten years of age with a severe degree of angulation, displacement uncorrected over 4 mm, concomitant posterior dislocation of the elbow, treatment by open reductions supplemented with transcapitellar wires, and a fracture treated by late open reduction without osteotomy.
Effect of calcitonin on fractional delivery of sodium and solutes to the juxtamedullary end-descending limb of the rat.
The purpose of the present studies was to examine, by micropuncture, the effect of salmon calcitonin on fractional sodium and solutes deliveries to the juxtamedullary end-descending limb of the rat. All animals were postprandial and thyroparathyroidectomized Munich-Wistar rats. Group 1 (N = 8) consisted of time control water-diuretic rats; group 2 (N = 8) received synthetic salmon calcitonin (10 mU/min) intravenously while undergoing water diuresis; group 3 (N = 8) was treated as group 2 but also received calcium intravenously to prevent the calcitonin-induced fall in plasma calcium. Calcitonin, alone and with calcium, produced a marked fall in urine flow rate and a marked increase in urinary osmolality. Concomitant fractional water delivery to the end-descending limb fell significantly (28 +/- 0.8 to 21 +/- 1.0%, p less than 0.05), while fractional solute and sodium deliveries increased significantly (36 +/- 1.3 to 55 +/- 2.6%, p less than 0.05; 34 +/- 2.0 to 48 +/- 3.5%, p less than 0.05, respectively). The three groups did not significantly differ in fractional water and sodium deliveries to the superficial end-accessible proximal tubule. We conclude that salmon calcitonin is antidiuretic in the rat and that it also produces an increase in fractional sodium and total solute deliveries to the end-descending limb, which we suggest is due to transepithelial sodium addition. The physiological significance of these observations to water homeostasis in vivo remains to be determined.