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Biomedical subjects

D Zimmerman

Publications and source records attributed to D Zimmerman.

At least 19 recordsLinked to original sources
PubMed1992

Radiation therapy for diabetes insipidus caused by Langerhans cell histiocytosis.

Hypothalamic-pituitary radiation therapy has been the standard treatment for the diabetes insipidus of Langerhans cell histiocytosis. The goal of this study was to assess the role of radiation therapy in Langerhans cell histiocytosis-associated diabetes insipidus and to compare the results with nonirradiated controls. Forty-seven patients with pathologically confirmed Langerhans cell histiocytosis were diagnosed with diabetes insipidus between 1950 and 1989 and were treated at the Mayo Clinic. These patients were divided into two groups on the basis of treatment for the diabetes insipidus: The first group (radiation group) included 30 patients (28 of whom were evaluable for response) who received hypothalamic-pituitary radiation therapy, and the second group (control group) included 17 patients who did not. A partial response to treatment was defined as a reduction in vasopressin dosage or improvement in computed tomography (CT) or magnetic resonance imaging (MRI). A complete response was defined as no further need for vasopressin therapy or normalization of CT or MRI. End points analyzed included treatment response, patient characteristics, morbidity, dose-response relationship, and survival. Patient characteristics of the two groups were similar except for age and lung involvement, both of which were significantly less in the radiation group. Thirty-six percent of patients (10 of 28) in the radiation group responded to hypothalamic-pituitary radiation therapy (22% complete response and 14% partial response), whereas none in the control group responded. Five of the six complete responders were irradiated within 14 days of the diagnosis of diabetes insipidus. The mean dose used in the responding and nonresponding patients was 11.2 and 10 Gy, respectively. Three of five patients (60%) treated with more than 15 Gy responded compared to seven of 23 (30%) treated with less than 15 Gy. Eight of the 10 responders (80%), compared to 16 of 35 nonresponders (46%), were female. Only one in 20 patients with concomitant lung histiocytosis responded. Complications of therapy may include insufficiency in other hypothalamic-pituitary axes in the treated patients. Actuarial survivals at 5, 10, 20, and 40 years for the entire group were 80%, 78%, 75%, and 65%, respectively, with a median follow-up in living patients of 14.7 years.

Adolescent↗
PubMed1992

Tibia vara in a patient with Bardet-Biedl syndrome.

The Bardet-Biedl syndrome is characterized by polydactyly, hypogonadism, obesity, mental retardation, and retinitis pigmentosa. Several other skeletal findings include hip dysplasia, short stature, and skull deformities. The patient described in this report has the classic findings of Bardet-Biedl syndrome in conjunction with tibia vara and irregular physes of the lower extremities.

Abnormalities, Multiple↗
PubMed1991

Medicaid spenddown among nursing home residents in Wisconsin.

We examined Medicaid spenddown among nursing home residents from 72 facilities in Wisconsin during 1988. Results indicate that only a small proportion (12%) of discharges from these facilities had spent down to Medicaid eligibility. This represents about one-fourth (23%) of persons who had been admitted private pay. Moreover, we estimated that over 40% of those who spent down to Medicaid did so within 6 months, 58% spent down within a year, and 76% spent down within 2 years. Even though a relatively small percentage of residents spent down, this group had very long stays (median stay greater than 3 years) and thus contributed quite heavily to nursing home days.

Aged↗
PubMed1991

Reconsiderations of the routine and preferential use of lidocaine in the emergent treatment of ventricular arrhythmias.

OBJECTIVE: Despite a history of widespread use, the utility of lidocaine as an antiarrhythmic and antifibrillatory agent is questionable. The objective of this article is to examine the theoretical basis for the use of lidocaine in light of recent experimental and clinical data. This article reviews the effects of lidocaine on: a) ventricular arrhythmias under ischemic and nonischemic conditions; b) the energy and current requirements for defibrillation; and c) the propensity for asystole during cardiac arrest. DESIGN: A contemporary review of the literature. FINDINGS: There appears to be a theoretical basis for the use of lidocaine in treating ventricular arrhythmias secondary to acute ischemia largely based on voltage- and pH-dependent binding and inactivation of sodium channels by lidocaine under ischemic conditions. However, clinical and experimental data failed to establish enhanced survival following prophylactic treatment for acute ischemic events or when treatment is administered during cardiac arrest. Moreover, there are no data supporting the use of lidocaine in treating sustained and life-threatening ventricular arrhythmias in the absence of acute ischemia. Experimental data demonstrate that lidocaine can reduce countershock efficacy, i.e., increase the current and energy requirements for defibrillation. Experimental and clinical data suggest that the administration of lidocaine increases the propensity for asystole during cardiac arrest. CONCLUSIONS: While lidocaine may possess an antifibrillatory effect under experimental conditions, the clinical relevance of such an effect is questionable. If cardiac arrest occurs, lidocaine has limited utility and may be deleterious secondary to diminished countershock efficacy or lidocaine-induced asystole. Reconsideration of the use of lidocaine should be included in future guidelines for management of cardiac arrest.

Arrhythmias, Cardiac↗
PubMed1991

Limitations of the countershock dose response: a study of transthoracic current.

Dose response assessment of countershock efficacy has been widely determined with respect to energy but not current. The purpose of this study was to examine the utility of the dose response method in a current-based model of transthoracic defibrillation (pentobarbital anesthetized dogs, n = 8). Ventricular fibrillation induction lasting 15 seconds was separated by 5-minute intervals. Current defibrillation threshold (DFT; the lowest current that successfully defibrillated) was determined by decreasing current on successive trials. Energy DFT equaled the energy value of the corresponding current DFT. Subsequent data were expressed in normalized terms with each DFT assigned a normalized value of 1.00. Three shocks were delivered in random order at each of seven normalized current nodes (total of 21 shocks): 0.55, 0.70, 0.85, 1.00, 1.15, 1.30, and 2.00 x DFT (early testing). Randomization was repeated, and a second set of 21 trials were performed (late testing). Composite plots were made relating normalized current and energy to the percent successful defibrillation. The dose response expressed in normalized energy demonstrated an overall shift to the left compared to current. The difference was significant at every node value below the estimated DFT. Ninety percent of successful trials with respect to current and energy occurred at or above 0.85 DFT and 0.55 DFT, respectively. Significant changes in impedance occurred between early testing (60 +/- 6 ohms) and late testing (47 +/- 5 ohms), n = 8, mean +/- SD. Current, compared to energy, is a more accurate parameter in the dose response assessment of transthoracic defibrillation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Hyperthyroidism in children and adolescents.

Hyperthyroidism in infants and children usually is caused by Graves' disease; however, several other diseases can also produce hyperthyroidism in these age groups. Because the pathophysiology and clinical course of these conditions differ, optimal treatment depends on precise diagnosis.

Adolescent↗
PubMed1990

Late juvenile-onset Krabbe's disease.

Krabbe's disease is an autosomal recessive leukodystrophy characterized by a lack of galactocerebroside beta-galactosidase activity. In contrast to the classic early infantile-onset form of Krabbe's disease, less recognized, late-onset variants exist. The authors present a case of late juvenile-onset Krabbe's disease, including the associated magnetic resonance imaging (MRI) findings. Most patients with late-onset Krabbe's disease present with visual loss due to optic atrophy. Associated gait abnormalities and parental consanguinity should increase the clinician's suspicion that a child may have late-onset Krabbe's disease. Because of the prolonged survival in late-onset Krabbe's disease, the recent development of bone marrow transplantation for these patient makes diagnosis of this disorder particularly important.

Adolescent↗
PubMed1989

Medullary carcinoma in children. Results of early detection and surgery.

Early diagnosis and surgical treatment of medullary carcinoma of the thyroid (MCT) in children is essential to decrease the likelihood of metastatic spread. To determine the optimal timing of screening and surgery, we reviewed all children younger than 16 years old who were undergoing surgical treatment. From 1970 to 1988, 33 children 6 months old to 15.9 years old (mean, 9 years old) with MCT or C-cell hyperplasia or both underwent total thyroidectomy. Follow-up was 4 months to 15 years after surgery (mean, 9 years). Six of 31 patients presented with a neck mass. Basal immunoreactive calcitonin level was increased in 3 of 7 patients with C-cell hyperplasia alone, in 10 of 18 patients with nonmetastatic MCT, and in all 5 patients with metastatic MCT. At the time of surgery, 7 patients had C-cell hyperplasia, 19 patients had MCT without metastasis, and 7 patients had MCT with metastases. All children with metastasis were more than 12 years old. Medullary carcinoma of the thyroid was seen as early as age 6 months in a child with multiple endocrine neoplasia type IIb (MEN-IIb) and age 3 years in a child with MEN-IIa. At follow-up, 25 patients were free of disease and 8 had had recurrent disease. Two of the 8 patients with MEN-IIb had died. All 6 children with a neck mass at presentation had recurrent disease. Of 27 patients diagnosed by screening, 25 had no evident disease and 2 had persistent disease. Thus, in children with MEN-II syndromes, screening studies are highly effective in detecting MCT. All children with MEN-IIb should be studied shortly after birth, and those with MEN-IIa should be studied by 1 year old.

Adolescent↗
PubMed1989

Nursing home case mix in Wisconsin. Findings and policy implications.

Along with many other states, Wisconsin is considering a case mix approach to Medicaid nursing home reimbursement. To support this effort, a nursing home case mix model was developed from a representative sample of 410 Medicaid nursing home residents from 56 facilities in Wisconsin. The model classified residents into mutually exclusive groups that were homogeneous in their use of direct care resources, i.e., minutes of direct care time (weighted for nurse skill level) over a 7-day period. Groups were defined initially by intense, Special, or Routine nursing requirements. Within these nursing requirement categories, subgroups were formed by the presence/absence of behavioral problems and dependency in activities of daily living (ADL). Wisconsin's current Skilled/Intermediate Care (SNF/ICF) classification system was analyzed in light of the case mix model and found to be less effective in distinguishing residents by resource use. The case mix model accounted for 48% of the variance in resource use, whereas the SNF/ICF classification system explained 22%. Comparisons were drawn with nursing home case mix models in New York State (RUG-II) and Minnesota. Despite progress in the study of nursing home case mix and its application to reimbursement reform, methodologic and policy issues remain. These include the differing operational definitions for nursing requirements and ADL dependency, the inconsistency in findings concerning psychobehavioral problems, and the problem of promoting positive health and functional outcomes based on models that may be insensitive to change in resident conditions over time.

Activities of Daily Living↗
PubMed1988

Cardiorenal endocrine dynamics during volume expansion in hypothyroid dogs.

To address the role of atrial natriuretic factor (ANF) in hypothyroidism in the control of cardiorenal-endocrine function during volume loading, the relationships between atrial pressure, ANF, the renin-angiotensin-aldosterone system, and renal hemodynamic and excretory function were examined during and after acute 10% body wt saline volume infusion in pentobarbital-anesthetized hypothyroid dogs (n = 8). Hormonal changes before and after thyroidectomy were also evaluated. Four to 6 wk after thyroidectomy, ANF decreased and arginine vasopressin (AVP) and plasma renin activity (PRA) increased. Acute saline volume expansion caused an increase in ANF and decreases in AVP and PRA. Atrial pressure increased throughout volume expansion. Despite the absence of an increase in glomerular filtration rate (GFR) during volume expansion, urinary sodium excretion increased due to a marked rise in fractional excretion of sodium. These studies demonstrate that in hypothyroidism 1) ANF is decreased; 2) despite the decrease in basal ANF, increases in atrial pressure can stimulate relase of ANF; 3) despite the absence of an increase in GFR during volume expansion, fractional excretion of sodium increases associated with an increase in ANF; and 4) a lack of an increase in GFR during volume expansion is not related to an inability to increase ANF.

Aldosterone↗
PubMed1988

Papillary thyroid carcinoma in children and adults: long-term follow-up of 1039 patients conservatively treated at one institution during three decades.

Fifty-eight children (18 boys, 40 girls) less than 17 years of age, undergoing initial surgery because of papillary thyroid carcinoma (PTC) at Mayo Clinic from 1946 through 1975 and followed up for a median time of 27.6 years were compared with 981 adults (323 men, 658 women) treated during the same period and followed up for a median period of 19.5 years. At initial evaluation, mean tumor size (+/- SD) was greater in children (3.1 +/- 1.7 cm) than in adults (2.1 +/- 1.7 cm) (p less than 0.001); tumor DNA content was nondiploid in 10% of 39 children and in 25% of 110 adults (p = 0.047). Neck node metastases at diagnosis were detected in more children (89.7%) than adults (34.7%) (p less than 0.0001), but extrathyroidal invasion was not significantly more frequent in children (24.1%) than adults (15.8%) (p = 0.095). Distant metastases at diagnosis were detected in more children (6.9%) than adults (2.1%) (p = 0.022). Postoperatively, neck node metastases recurred more frequently in children (30%) than in adults (7%) (p less than 0.001), but local neck recurrences were not significantly more frequent in children (12%) than in adults (5%) (p = 0.083). Postoperative distant metastases occurred with similar frequency in children (6%) and adults (5%) (p = 0.98). Survival (all causes of death) for both adults and children up to 30 years after the initial surgery was no different from expected survival rates. Only adults aged more than 40 years had a significantly higher mortality from PTC than did children (p less than 0.0001). Fourteen percent of children had died of PTC by 15 years after diagnosis of distant metastases, whereas 68% of similarly affected adults were dead at 15 years (p = 0.014). PTC was more often metastatic to neck nodes and lungs before initial surgery and more often recurrent in neck lymph nodes postoperatively. However, PTC tended to be less fatal in children, and this may be related to the infrequency of nondiploid DNA content in the childhood PTC tumors.

Adolescent↗