Marc B. Goldstein

The effects of antitumor irradiation on mandibular opening and mobility: A prospective study of 58 patients

OBJECTIVE The purpose of this study was to analyze the effects of head and neck radiation therapy on jaw opening and mobility. STUDY DESIGN Maximum jaw opening and mandibular mobility were measured before and after radiation treatment in 58 patients presenting for angle down wedge, homolateral wedge pair, and parallel pair head and neck radiation treatment. RESULTS As dose to the temporomandibular joint and pterygoid muscles increased, maximal jaw opening decreased linearly. Mandibular dysfunction appeared to increase as radiation dose to the pterygoid muscles increased. Similar effects were not observed with temporomandibular joint irradiation. Irradiation of the pterygoid muscles appeared critical in the development of trismus. Angle down wedge treatment irradiated the temporomandibular joint and pterygoid muscles with clinical effects similar to those seen in homolateral wedge pair and parallel pair patients. Doses as low as 1493 cGy resulted in functional impairment. CONCLUSIONS Future investigations into radiotherapy delivery and appropriate postradiation trismus treatment may reduce head and neck radiation morbidity.

Comparison of Subcutaneous and Intravenous Recombinant Human Erythropoietin for Anemia in Hemodialysis Patients with Significant Comorbid Disease

While recombinant human erythropoietin (rHuEPO) is an effective therapy for anemia in renal failure, most published studies concern benefits in relatively healthy hemodialysis patients. The present study compares intravenous and subcutaneous administration of rHuEPO in an unselected group of 128 hemodialysis patients who were randomized to receive rHuEPO in an initial dose of 150 U/kg/week in three divided doses by subcutaneous or intravenous injection. Following a 4-week placebo run-in period, patients received rHuEPO until their hemoglobin was stable between 105 and 125 g/l for 4 weeks and then followed for a further 24 weeks. Eighty-three patients completed the study, 45 in the subcutaneous and 38 in the intravenous group. There was no difference in mean hemoglobin at any stage between subcutaneous and intravenous patients. Mean rHuEPO dose at the time of stabilization was significantly lower in the subcutaneous group compared to the intravenous (205.9 +/- 135.4 vs. 274.1 +/- 142.4 U/kg/week; p = 0.019), mean time to hemoglobin target was 9.9 +/- 4.5 weeks for the subcutaneous group and 11.9 +/- 4.9 weeks for the intravenous group (p = 0.037). Time to stabilization was 14.9 +/- 4.7 weeks for the subcutaneous compared to 17.3 +/- 3.9 weeks for the intravenous group (p = 0.006). Diabetic patients had higher dose requirements for rHuEPO at all time points and required a longer time to reach stabilization than nondiabetics (18.6 +/- 4.6 vs. 15.6 +/- 4.3 weeks; p = 0.016). Quality of life estimated by a disease-specific Kidney Disease Questionnaire improved significantly during rHuEPO therapy in both groups. There was no significant change in dialysis prescription throughout the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Urea Kinetic Modelling in Chronic Hemodialysis: Benefits, Problems, and Practical Solutions

Urea kinetic modelling principles have several a p plications in clinical nephrology. They are useful in the assessment of dietary therapy in patients with chronic progressive renal disease and in the monitoring of the nutritional state of patients with acute renal failure (1-5). However, the most extensive current application is for the assessment of the adequacy of dialysis and nutrition in chronic hemodialysis patients (6,7). In this review we shall focus on. this latter application, beginning with a discussion of the principles of urea kinetic modelling in chronic hemodialysis patients, thereafter an explanation of the basis of the problems experienced by clinicians applying these principles and concluding with a simple, accurate and practical method to assess urea kinetics in the clinical setting.

A simple method to create buttonhole cannulation tracks in a busy hemodialysis unit

The preference for fistulae as the hemodialysis access of choice has led to a significant number of accesses that are less than ideal for cannulation. Buttonhole cannulation is ideal for such accesses, but the technique for creation provides major challenges. In 12 patients, buttonhole tunnel tracks were created by leaving the polyurethane catheter of a Clampcath® hemodialysis needle indwelling for 10 days after the initial cannulation. After each dialysis the catheter was flushed, and dressed with an antibacterial ointment and gauze. Dialysis was carried out via the catheter during that time. After day 10, the catheter was removed, the tunnel track covered with an antibacterial dressing and the tunnel track was cannulated with a dull buttonhole needle at the next dialysis. Successful buttonhole accesses were created in 11 patients after 10 days, the 12th patient required a single sharp needle cannulation before using dull needles. During the first 2 weeks of dull needle cannulation both pain experienced on cannulation and the difficulty cannulating the access were significantly less than in the classical buttonhole technique (P<0.01). Complications during the follow‐up period (6 months–1.5 years) included difficulty cannulating with a dull needle (22) and antibacterial agent induced contact dermatitis (4). There was no episode of sepsis or tunnel track infection. Initial cannulation of the fistula using a Clampcath® hemodialysis needle, leaving the polyurethane catheter indwelling for 10 days, is a simple, safe, and effective technique for the creation of buttonhole tunnel tracks.

Renal excretion of uric acid during prolonged fasting

Serum and urine uric acid were evaluated during prolonged therapeutic fasting in 15 obese patients. With increasing ketonemia the serum uric acid rose from a control value of 5.9 +/- 0.4 to 12.5 +/- 1.0 mg/100 ml at 7 days and then decreased progressively to 7.7 +/- 1.3 mg/100 ml by 28 days despite sustained ketonemia. The uric acid clearance were 5.5 +/- 0.9, 1.8 +/- 0.2, and 4.4 +/- 1.5 ml/min at days 0, 7, and 25 of fasting. At the same times the creatinine clearances were 114 +/- 11, 80 +/- 6, and 64 +/- 6.3 ml/min. There was no evidence of a renal tubular abnormality as assessed by glycosuria, bicarbonaturia, or increased phosphaturia. Urate binding to plasma proteins remained unchanged. Acute studies of the renal handling of uric acid revealed a uricosuric response to the administration of sodium lactate or sodium bicarbonate by intravenous infusion and low-dose acetylsalicylic acid orally. This renal tubular response departs significantly from that observed during the overnight fasted state and could not be accounted for by extracellular fluid volume expansion or the induced acid-base changes.

A Specimen Positioning Device for Dental Radiographic Identification—Image Geometry Considerations

Preventative dental treatment has reduced caries incidence and thereby rendered dental identification, in caries-free individuals, more difficult. An alternate method comparing spatial relationships of dental structures in digitized superimposed antemortem and postmortem radiographs has been previously developed. This paper examined the limitations of this technique and demonstrates a positioning device suitable for reproducing antemortem radiographic image geometry. The paper also examined three specific aspects of image geometry namely horizontal angulation, vertical angulation and focal film distance. Deviations in horizontal angulations between antemortem and postmortem radiographs by as little as 5 degrees makes identification difficult. Changes in vertical angulation or focal-film distance had no affect. This procedure, and the positioning device used to accurately replicate antemortem image geometry is an economical, easy to use adjunct to current methods of dental identification.

Comparative Assessment of 2-Dimensional Echocardiography vs Cardiac Magnetic Resonance Imaging in Measuring Left Ventricular Mass in Patients With and Without End-Stage Renal Disease

BACKGROUND While echocardiography (ECHO)-measured left ventricular mass (LVM) predicts adverse cardiovascular events that are common in hemodialysis (HD) recipients, cardiac magnetic resonance imaging (CMR) is now considered the reference standard for determination of LVM. This study aimed to evaluate concordance between LVM measurements across ECHO and CMR among chronic HD recipients and matched controls. METHODS A single-centre, cross-sectional study of 41 chronic HD patients and 41 matched controls with normal kidney function was performed to compare LVM measurements and left ventricular hypertrophy (LVH) designation by ECHO and CMR. RESULTS In both groups, ECHO, compared with CMR, overestimated LVM. Bland-Altman analysis demonstrated wider agreement limits in LVM measurements by ECHO and CMR in the chronic HD group (mean difference, 60.8 g; limits -23 g to 144.6 g) than in the group with normal renal function (mean difference, 51.4 g; limits -10.5 g to 113.3 g). LVH prevalence by ECHO and CMR in the chronic HD group was 37.5% and 22.5%, respectively, while 17.5% and 12.5% had LVH by ECHO and CMR, respectively, in the normal kidney function group. Intermodality agreement in the designation of LVH was modest in the chronic HD patients (κ = 0.42, P = 0.005) but strong (κ = 0.81, P < 0.001) in the patients with preserved kidney function. Agreement was strong in assessing LVH by ECHO and CMR only in those with normal kidney function. CONCLUSIONS Our results suggest that the limitations of LVM measurement by ECHO may be more pronounced in patients receiving HD, and provide additional support for the use of CMR in research and clinical practice when rigourous assessment of LVM is essential.

Pathogenesis of acidosis in hereditary fructose intolerance

An 18-yr-old man with a classical history of hereditary fructose intolerance (HFI) developed typical biochemical changes following an oral fructose load: fructosemia, hypoglycemia, hypophosphatemia, hyperuricemia, and metabolic acidosis. Hypokalemia (3.1 meq/liter) was also noted. Three aspects of this case expand the published literature on this syndrome: (1) Metabolic acidosis was found to be due to both lactic acidosis and proximal renal tubular acidosis (RTA). We could quantitate the relative contribution of each, and found that urinary bicarbonate loss due to proximal RTA accounted for less than 10% of the fall in serum bicarbonate. The major cause of the metabolic acidosis was lactic acidosis. (2) Hypokalemia was found to be due to movement of potassium out of the extracellular space rather than to urinary loss. Potassium may have entered cells with phosphate or may have been sequestered in the gastrointestinal tract. (3) The coexistence of proximal RTA and acidemia made it possible to study the effect of acidemia on the urine-blood partial pressure of carbon dioxide (PCO2) gradient in alkaline urine (U-B PCO2). The U-B PCO2 measured during acidemia was much higher at the same urine bicarbonate concentration than in normal controls during alkalemia, providing evidence in humans that acidemia stimulates distal nephron hydrogen-ion secretion.

Evaluation of the effect of pentobarbitone anaesthesia on the plasma potassium concentration in the rabbit and the dog

The purpose of these studies was to determine the reasons for the hypokalaemia observed in rabbits studied in our laboratory. The rabbits consumed standard rabbit chow which is rich in potassium and remained in potassium balance. Hypokalaemia was only observed following anaesthesia. A number of additional investigations were undertaken to clarify the mechanisms involved. The hypokalaemia could not be attributed to technical factors, alkalaemia, hyperinsulinaemia or hyperaldosteronism, but seemed to be a function of anaesthesia. This effect of pentobarbitone anaesthesia was not unique to the rabbit, as similar changes also occurred in the anaesthetized dog.The findings reported in this paper have significant implications with respect to the interpretation of plasma potassium concentrations in anaesthetized subjects or animals.RésuméLe but de cette eétude était de déterminer la cause de l’hypokaliémie observée à la suite de l’anesthésie des lapins de laboratoire. Ces lapins consommaient une moulée standard à lapins riche en potassium et capable de maintenir en balance cet électrolyte. Plusieurs investigations supplémentaires furent entreprises pour élucider les mécanismes responsables. La baisse de la kaliémie ne put être attribuée à des facteurs techniques, à l’alcalémie, l’hyperinsulinémie ou 1’hyperaldostéronisme mais semblait bien être une conséquence de l’anesthésie au pentobarbitone. Cet effet ne survenait pas uniquement sur les lapins mais aussi sur les chiens anesthesies.Les données rapportées dans ce travail peuvent modifier significativement 1’interprétation des résultats d’analyse de la kaliémie plasmatique chez les patients et les animaux anesthésiés.

Perirenal lymphocyst formation in renal transplant recipients Diagnosis and pathogenesis

Perirenal lymphocyst formation occurred in 7 of 46 consecutive renal allografts which had survived at least one month. This complication developed from one to four and one-half months post-transplantation, resulted in a specific spectrum of clinical signs and symptoms, and was best diagnosed by a combination of intravenous pyelography and ultrasonic examination of the transplanted kidney. The lymph fluid is of recipient origin and its collection appears to be related to use of a high-dose immunosuppressive regimen and to a conscious decision to avoid the use of postoperative surgical drains. Surgical intraperitoneal marsupialization of the lymphocyst emerges as the clear treatment of choice for peritransplant lymphocyst formation.