Showing papers by "Mayo Clinic published in 1992"

Hip fractures in the elderly: A world-wide projection

Abstract: Hip fractures are recognized to be a major public health problem in many Western nations, most notably those in North America, Europe and Oceania. Incidence rates for hip fracture in other parts of the world are generally lower than those reported for these predominantly Caucasian populations, and this has led to the belief that osteoporosis represents less of a problem to the nations of Asia, South American and Africa. Demographic changes in the next 60 years, however, will lead to huge increases in the elderly populations of those countries. We have applied available incidence rates for hip fracture from various parts of the world to projected populations in 1990, 2025 and 2050 in order to estimate the numbers of hip fractures which might occur in each of the major continental regions. The projections indicate that the number of hip fractures occurring in the world each year will rise from 1.66 million in 1990 to 6.26 million by 2050. While Europe and North America account for about half of all hip fractures among elderly people today, this proportion will fall to around one quarter in 2050, by which time steep increases will be observed throughout Asia and Latin America. The results suggest that osteoporosis will truly become a global problem over the next half century, and that preventive strategies will be required in parts of the world where they are not currently felt to be necessary.

APC mutations occur early during colorectal tumorigenesis.

Abstract: HUMAN tumorigenesis is associated with the accumulation of mutations both in oncogenes and in tumour suppressor genes1–3 But in no common adult cancer have the mutations that are critical in the early stages of the tumorigenic process been defined We have attempted to determine if mutations of the APC gene play such a role in human colorectal tumours, which evolve from small benign tumours (adenomas) to larger malignant tumours (carcinomas) over the course of several decades Here we report that sequence analysis of 41 colorectal tumours revealed that the majority of colorectal carcinomas (60%) and adenomas (63%) contained a mutated APC gene Furthermore, the APC gene met two criteria of importance for tumour initiation First, mutations of this gene were found in the earliest tumours that could be analysed, including adenomas as small as 05 cm in diameter Second, the frequency of such mutations remained constant as tumours progressed from benign to malignant stages These data provide strong evidence that mutations of the APC gene play a major role in the early development of colorectal neoplasms

Streptozocin–Doxorubicin, Streptozocin–Fluorouracil, or Chlorozotocin in the Treatment of Advanced Islet-Cell Carcinoma

Abstract: Background. The combination of streptozocin and fluorouracil has become the standard therapy for advanced islet-cell carcinoma. However, doxorubicin has also been shown to be active against this type of tumor, as has chlorozotocin, a drug that is structurally similar to streptozocin but less frequently causes vomiting. Methods. In this multicenter trial, we randomly assigned 105 patients with advanced islet-cell carcinoma to receive one of three treatment regimens: streptozocin plus fluorouracil, streptozocin plus doxorubicin, or chlorozotocin alone. The 31 patients in whom the disease did not respond to treatment were crossed over to chlorozotocin alone or to one of the combination regimens. Results. Streptozocin plus doxorubicin was superior to streptozocin plus fluorouracil in terms of the rate of tumor regression, measured objectively (69 percent vs. 45 percent, P = 0.05), and the length of time to tumor progression (median, 20 vs. 6.9 months; P = 0.001). Streptozocin plus doxorubicin also ha...

MR-based hippocampal volumetry in the diagnosis of Alzheimer's disease.

Abstract: We evaluated a new magnetic resonance (MR)-based technique for performing volumetric measurements of temporal lobe structures. The technique was designed to assist in making the clinical diagnosis of dementia of the Alzheimer type (DAT). We chose specific anatomic regions of interest because of their known involvement in memory function and in the neuropathology of DAT and used a regression model to assess the effects of age on the volumes of the anterior temporal lobe (ATL) and the hippocampal formation (HF). These measurements were normalized by total intracranial volume (TIV). The volumetric measurements of both the normalized ATL and HF were significantly smaller (p less than 0.001) in DAT patients (N = 20) than in controls (N = 22), but the HF volumes provided much better separation between the two groups. Eighty-five percent of the DAT patients fell below the range of the HF/TIV measurement for the control subjects. This separation held up over the entire age range studied. Normalized volumes of both the HF and ATL decreased with age significantly for both the DAT patients and the controls. These results support the contention that MR-based HF volumetric measurements are accurate in differentiating DAT patients from cognitively normal elderly individuals. This technique may be a useful adjunct in making the clinical diagnosis of DAT.

Treatment of Postmenopausal Osteoporosis with Transdermal Estrogen

Abstract: ▪Objective:To evaluate the tolerance and effectiveness of transdermal estrogen for women with established postmenopausal osteoporosis and vertebral fractures. ▪Design:Double-blind, randomi...

The frequency of familial dilated cardiomyopathy in a series of patients with idiopathic dilated cardiomyopathy

Abstract: Background. Dilated cardiomyopathy is characterized by an increase in ventricular size and impairment of ventricular function. Most cases are believed to be sporadic, and familial dilated ...

A community-based study of the epidemiology of asthma. Incidence rates, 1964-1983.

Abstract: To determine whether the incidence of asthma had increased in Rochester, Minnesota, from January 1, 1964 through December 31, 1983, we used a population-based computer-linked medical diagnosis system to identify individual medical records with diagnosis of asthma or other conditions mimicking asthma. All records were reviewed using explicit predetermined diagnostic criteria; we identified 3,622 incident cases of asthma, including definite asthma (n = 1,547), probable asthma (n = 952), and single wheezing episodes (n = 1,123). The annual age- and sex-adjusted incidence of definite + probable asthma rose from 183 per 100,000 in 1964 to 284 per 100,000 in 1983. This rise was entirely accounted for by increased incidence rates in children and adolescents (age range, 1 to 14 yr); incidence rates for infants younger than 1 yr of age and for adults remained constant. For definite + probable asthma cases, the incidence rates for males were higher than for females from infancy through 9 yr of age and for persons older than 50; incidence rates for females were higher than for males from 15 through 49 yr of age. The median age at onset was 3 yr for males and 8 yr for females. We conclude that asthma begins in early childhood, with a higher incidence and earlier onset in males, and that the increase in incidence rates seen from 1964 to 1983 occurred only in children and in adolescents.

Regulation of fracture repair by growth factors.

Abstract: Fractured bones heal by a cascade of cellular events in which mesenchymal cells respond to unknown regulators by proliferating, differentiating, and synthesizing extracellular matrix. Current concepts suggest that growth factors may regulate different steps in this cascade (10). Recent studies suggest regulatory roles for PDGF, aFGF, bFGF, and TGF-beta in the initiation and the development of the fracture callus. Fracture healing begins immediately following injury, when growth factors, including TGF-beta 1 and PDGF, are released into the fracture hematoma by platelets and inflammatory cells. TGF-beta 1 and FGF are synthesized by osteoblasts and chondrocytes throughout the healing process. TGF-beta 1 and PDGF appear to have an influence on the initiation of fracture repair and the formation of cartilage and intramembranous bone in the initiation of callus formation. Acidic FGF is synthesized by chondrocytes, chondrocyte precursors, and macrophages. It appears to stimulate the proliferation of immature chondrocytes or precursors, and indirectly regulates chondrocyte maturation and the expression of the cartilage matrix. Presumably, growth factors in the callus at later times regulate additional steps in repair of the bone after fracture. These studies suggest that growth factors are central regulators of cellular proliferation, differentiation, and extracellular matrix synthesis during fracture repair. Abnormal growth factor expression has been implicated as causing impaired or abnormal healing in other tissues, suggesting that altered growth factor expression also may be responsible for abnormal or delayed fracture repair. As a complete understanding of fracture-healing regulation evolves, we expect new insights into the etiology of abnormal or delayed fracture healing, and possibly new therapies for these difficult clinical problems.

Epidemiology of osteoporosis

Abstract: Osteoporosis is a major public health problem through its association with age-related fractures. Although fracture risk at any skeletal site depends upon a complex interaction between bone strength and trauma, recent epidemiologic studies confirm that bone density is currently the best single predictor of future fracture. The increasing burden of osteoporotic fractures urgently requires effective preventive strategies aimed at maximizing peak bone density, preventing excessive bone loss, and reducing the risk of falls.

Incidence and risk factors for side effects of spinal anesthesia

Abstract: We prospectively studied 952 patients to identify the incidence of hypotension (systolic blood pressure < 90 mmHg), bradycardia (heart rate < 50 beats/min), nausea, vomiting, and dysrhythmia during spinal anesthesia. Historical, clinical, and physiologic data were correlated with the incidence of th

Aneurysmal bone cyst. A clinicopathologic study of 238 cases.

Abstract: Aneurysmal bone cyst (ABC) is a nonneoplastic expansile bone lesion that mainly affects children and young adults. Primary ABC is relatively rare, with an incidence one half that of giant cell tumor of bone. In 238 patients with ABC studied in the Mayo Clinic files, more than 80% of the lesions were in long bones, flat bones, or the spinal column. Of the lesions initially treated at the Mayo Clinic, 95% were typical ABC; the rest were "solid" variants. Except for the absence of obvious cavernous channels and spaces, there was no significant histologic difference between solid variant and typical ABC. Radiographically, ABC is an eccentric expansile lesion commonly located at the metaphysis of long bones. Computed tomography and magnetic resonance imaging may show multiple internal septations or fluid levels. In the 153 patients treated, 19% had recurrence after curettage (intralesional excision). Recurrence was most common during the first 2 postoperative years.

Left ventricular dysfunction due to atrial fibrillation in patients initially believed to have idiopathic dilated cardiomyopathy.

Abstract: Ten patients aged 22 to 80 years (median 57) with severe left ventricular (LV) dysfunction and atrial fibrillation (AF) with rapid ventricular response were evaluated after therapy. Because most patients were unaware of their arrhythmia, duration was usually unknown. All patients had heart failure symptoms; 9 presented with New York Heart Association class III or IV disability, and 1 with class II disability. Initial LV ejection fraction ranged from 12 to 30% (median 25). No patient had symptomatic coronary artery disease (4 underwent angiography). Myocarditis and infiltrative processes were excluded by biopsy in 5 patients. All patients were considered initially to have idiopathic dilated cardiomyopathy with secondary AF. Ventricular rate was controlled in all patients, with sinus rhythm restored in 5. At follow-up (median 30 months, range 3 to 56), all patients were asymptomatic. LV ejection fraction after treatment ranged from 40 to 64% (median 52). It is concluded that in some patients initially considered to have idiopathic dilated cardiomyopathy, AF with rapid ventricular response may be the primary cause rather than the consequence of severe LV dysfunction. LV dysfunction may be completely reversible with ventricular rate control.

Five- to fifteen-year follow-up after Fontan operation.

Abstract: BACKGROUNDThe purpose of this study was to estimate survival and quality of outcome and assess factors associated with outcome for patients out 5 to 15 years from their Fontan operation.METHODS AND RESULTSWe studied 352 patients who had the Fontan operation prior to 1985. The overall 1-, 5-, and 10-year survival was 77%, 70%, and 60%, respectively. The following factors were significantly associated with lower survival: univentricular heart or complex congenital anomalies other than tricuspid atresia, early calendar year of operation, heterotaxia syndromes, early age at operation, increased pulmonary artery pressure, atrioventricular valve dysfunction, and higher (worse) New York Heart Association class. Reoperations were necessary for 103 of the 352 patients. At least 20% of the survivors have or have had cardiac arrhythmias requiring antiarrhythmic medication or mechanical pacemaker insertion. Between 7% and 10% of the patients have had or had protein-losing enteropathy/hypoproteinemia. At 5 years posto...

The influence of HLA-DRB1 genes on disease severity in rheumatoid arthritis

Abstract: OBJECTIVE: To explore the role of HLA-DRB1 genes in determining disease severity in rheumatoid arthritis. DESIGN: Case series of patients with seropositive rheumatoid arthritis. SETTING: The outpatient clinic of the Division of Rheumatology, Mayo Clinic. PATIENTS: One hundred and two patients with seropositive, erosive rheumatoid arthritis and a minimum disease duration of 3 years. MEASUREMENTS: Patients were genotyped for both HLA-DRB1 alleles and were categorized according to the expression of one or two disease-linked HLA-DRB1 alleles. Identification of HLA-DRB1 alleles was done by the polymerase chain reaction and subsequent oligonucleotide hybridization. Homozygosity for allelic variants was confirmed by sequence analysis. Immunogenetically defined patient subgroups were retrospectively evaluated for joint destruction and patterns of disease manifestation, including rheumatoid organ disease. RESULTS: Of 102 patients, 98 (96%) expressed the disease-linked sequence polymorphism. Forty-seven patients (46%) carried a double dose of the relevant sequence stretch: Twenty-eight patients expressed HLA-DRB1*04 variants on both alleles, and 19 combined an HLA-DRB*04 variant with HLA-DRB1*0101 or DRB1*1402. Nodular disease was present in 100% of patients typed as HLA-DRB1*04/04 and in 59% of patients typed as HLA-DRB1*04 and who had inherited only a single dose of the disease-linked sequence polymorphism (P < 0.0001). Major organ systems were involved in 61% and 11% of these two patient groups, respectively (P < 0.0001); and joint surgery was required in 61% and 25% (P < 0.002), respectively. Patients typed as HLA-DR*04/01 had intermediate clinical courses. CONCLUSION: Genotyping patients with rheumatoid arthritis for both HLA-DRB1 alleles identifies clinical subsets with distinct profiles of disease manifestations.

Elbow subluxation and dislocation. A spectrum of instability.

Abstract: After sequential releases of the ligaments and capsules of 13 fresh autopsy specimen elbows, external rotation and valgus moments with axial forces resulted in posterior dislocations in 12 of the 13 with the anterior medical collateral ligament (AMCL) intact. Kinematic displacements measured with a three-dimensional electromagnetic tracking device showed that dislocation involved posterolateral rotation of 34 degrees-50 degrees and 5 degrees-23 degrees valgus at about 80 degrees flexion. Dislocation is the final of three sequential stages of elbow instability resulting from posterolateral rotation, with soft-tissue disruption progressing from lateral to medial. In each stage, the pathoanatomy correlated with the pattern and degree of instability. Testing for valgus stability of the elbow during simulated active flexion revealed no significant increase (-0.3 degrees-2.4 degrees) in valgus laxity after reduction compared with the intact specimens (p greater than 0.05, beta = 0.1, delta = 2.5 degrees). In no case did the digitized AMCL origin-to-insertion distance increase beyond normal during the dislocation (p less than 0.01). The mechanism of dislocation during a fall on the outstretched hand would involve the body "rotating internally" on the elbow, which experiences an external rotation/valgus moment as it flexes. Posterior dislocations should therefore be reduced in supination. If valgus stability in pronation is demonstrated, the AMCL can be assumed to be intact, and rehabilitation in a hinged cast-brace with the elbow in full pronation can be commenced immediately.

Nondiffracting X waves-exact solutions to free-space scalar wave equation and their finite aperture realizations

Abstract: The authors report families of generalized nondiffracting solutions of the free-space scalar wave equation, and specifically, a subset of these nondiffracting solutions, which are called X waves. These nondiffracting X waves can be almost exactly realized over a finite depth of field with finite apertures and by either broadband or bandlimited radiators. With a 25-mm diameter planar radiator, a zeroth-order broadband X wave will have about 2.5-mm lateral and 0.17-mm axial -6-dB beam widths with a -6-dB depth of field of about 171 mm. A zeroth-order bandlimited X wave was produced and measured in water by a 10 element, 50-mm diameter, 2.5-MHz PZT ceramic/polymer composite J/sub 0/ Bessel nondiffracting annular array transducer with -6-dB lateral and axial beam widths of about 4.7 mm and 0.65 mm, respectively, over a -6-dB depth of field of about 358 mm. Possible applications of X waves in acoustic imaging and electromagnetic energy transmission are discussed. >

Semiconstrained arthroplasty for the treatment of rheumatoid arthritis of the elbow.

Abstract: Fifty-four patients in whom a total of fifty-eight semiconstrained modified Coonrad elbow implants had been inserted for rheumatoid arthritis were followed for a mean of 3.8 years (range, two to eight years). At the latest follow-up, there was little or no pain in fifty-three elbows (91 per cent). The arc of motion was from an average point in flexion of 20 degrees to an average point in flexion of 129 degrees, representing an average increase of 12 degrees of extension and 11 degrees of flexion. The average arc of pronation was 78 degrees, an increase of 14 degrees, and the average arc of supination was 77 degrees, an increase of 18 degrees. An additional ten patients who had had insertion of ten modified Coonrad implants during the same period were followed for less than two years but were included in the assessment of complications. Fifteen (22 per cent) of the sixty-eight elbows had a complication: four, infection; eight, acute or delayed condylar or ulnar fracture; and one each, ulnar neuritis, avulsion of the triceps, and fracture of the implant. Radiographic evaluation was performed for fifty-four of the fifty-eight elbows; the other four were excluded from this evaluation because of infection. A satisfactory radiographic appearance of the cement--its extent and the absence of skip areas--was noted for all of the ulnar components and for fifty-one (94 per cent) of the humeral components. No patient had radiographic evidence of a loose implant. A reoperation was performed in six elbows (10 per cent of the fifty-eight; 9 per cent of the sixty-eight): four were done for infection; one, for insufficiency of the triceps; and one, for a fractured ulnar component. Of the fifty-eight elbows, forty (69 per cent) had an excellent result; thirteen (22 per cent), a good result; four (7 per cent), a fair result; and one, a poor result.

Flexor tendon forces: In vivo measurements

Abstract: S-shaped force transducers were developed for measurement of the forces along intact tendons. After calibration, the transducers were applied to the flexor pollicis longus and flexor digitorum superficialis and profundus tendons of the index finger in five patients operated on for treatment of carpal tunnel syndrome. The tendon forces generated during passive and active motion of the wrist and fingers were recorded. For pinch function, the amount of the applied load was measured with a special pinch meter. Tendon forces in the range of 0.1 to 0.6 kgf were measured during passive mobilization of the wrist. Tendon forces up to 0.9 kgf were present during passive mobilization of the fingers. Tendon forces up to 3.5 kgf were present during active unresisted finger motion. Tendon forces up to 12.0 kgf were recorded during tip pinch, with a mean applied pinch force of 3.5 kgf. These results have potential application in determining the amount of force that a tendon repair would have to resist during passive as well as active postsurgical mobilizations.

Onset and Disappearance of Gastrointestinal Symptoms and Functional Gastrointestinal Disorders

Abstract: Functional gastrointestinal disorders, including the irritable bowel syndrome, account for up to 40% of referrals to gastroenterologists, but accurate data on the natural history of these disorders in the general population are lacking. Using a reliable and valid questionnaire, the authors estimated the onset and disappearance of symptoms consistent with functional gastrointestinal disorders. An age- and sex-stratified random sample of 1,021 eligible residents of Olmsted County, Minnesota, aged 30-64 years were initially mailed the questionnaire; 82% responded (n = 835). In a remailing to responders 12-20 months later, 83% responded again (n = 690). The age- and sex-adjusted prevalence rates per 100 for irritable bowel syndrome, chronic constipation, chronic diarrhea, and frequent dyspepsia were 18.1 (95% confidence interval (CI) 15.1-21.1), 14.7 (95% CI 11.9-17.4), 7.3 (95% CI 5.3-9.3), and 14.1 (95% CI 11.5-16.8), respectively, on the second mailing. Symptoms were not significantly associated with nonresponse to the second mailing; moreover, the estimated prevalence rates were not significantly different from the first mailing. Among the 582 subjects free of the irritable bowel syndrome on the first survey, 9% developed symptoms during 795 person-years of follow-up, while 38% of the 108 who initially had the irritable bowel syndrome did not meet the criteria after 146 person-years of follow-up. Similar onset and disappearance rates were observed for the other main symptom categories. While functional gastrointestinal symptoms are common in middle-aged persons and overall prevalence appears relatively stable over 12-20 months, substantial turnover is implied by the observed onset and disappearance rates; several potential sources of bias do not seem to account for this variation.

Perioperative blood transfusion and determinants of survival after liver resection for metastatic colorectal carcinoma.

Abstract: The authors reviewed their institutional experience with liver resection for metastatic colorectal carcinoma to (1) determine whether perioperative blood transfusion affects survival; (2) identify prognostic determinants; and (3) estimate the patient requirement for a prospective randomized trial designed to demonstrate efficacy of liver resection. Two hundred eighty consecutive patients treated by potentially curative liver resection between 1960 and 1987 were included. Data were obtained for all but 10 patients for at least 5 years after operation or through 1990. Actuarial survival curves related to potential prognostic determinants were analyzed with the log-rank test. Overall, survival was 47 +/- 3% at 3 years and 25 +/- 3% at 5 years, including 4% 60-day operative mortality rate. Eighty-one patients who did not receive blood 7 days before to 14 days after operation had 60 +/- 6% 3-year and 32 +/- 6% 5-year survival compared with 40 +/- 4% and 21 +/- 3% survival rates for 183 patients who received at least one unit (p = 0.03, operative deaths excluded). Extrahepatic disease (p = 0.015), extrahepatic lymph node involvement (p = 0.002), satellite configuration of multiple metastases (p = 0.0052), and initial detection by abnormal liver enzymes (p = 0.0005) were associated with poor survival rates. Synchronous presentation of metastatic and stage B primary disease was associated with a favorable prognosis (p = 0.003). The requirement for a prospective randomized trial estimated by an exponential survival model would be 36, 74, 168, or 428 patients if 5-year survival without resection were 1, 5, 10, or 15%. We conclude that (1) perioperative blood transfusion may be adversely associated with survival; (2) extrahepatic disease, extrahepatic lymph node involvement, satellite configuration, and initial detection by clinical examination or a liver enzyme abnormality portend a poor prognosis; and (3) a prospective randomized trial of liver resection is impractical because of the large patient requirement, at least by a single institution.

Magnetic resonance image-based hippocampal volumetry : correlation with outcome after temporal lobectomy

Abstract: We developed a magnetic resonance imaging (MRI)–based technique for measuring the volume of the hippocampal formation. In this study, the relationship between volumes of the hippocampal formation and outcome (i.e., postoperative seizure control) after anterior temporal lobectomy for intractable epilepsy was analyzed in 50 consecutive patients in whom the surgical specimen did not contain an epileptogenic mass lesion. Outcome was classified as either satisfactory or unsatisfactory. A significant relationship was found between outcome and volume of the operated of hippocampal formation (p = 0.012), as well as a derived volumetric measure (nonoperated minus operated volume of the hippocampal formation) (p = 0.004). The association between outcome and nonoperated volume was borderline (p = 0.057). Thirty-four (97%) of 35 patients in whom the volumetric study and electroencephalography (EEG) concordantly lateralized the seizure disorder had satisfactory postoperative seizure control. Conversely, only 7 (42%) of 12 patients in whom the volume study was nonlateralizing and 1 (33%) of 3 in whom the EEG and volume study were discordant had a satisfactory outcome. We regard our MRI-based study of hippocampal formation volume as a noninvasive surrogate for the identification of moderate or severe mesial temporal sclerosis. The technique is a useful adjunct in a multidisciplinary, preoperative epilepsy evaluation when T2-weighted MRIs do not reveal an epileptogenic mass lesion. The reasons for the usefulness of this imaging technique are: (1) It is an independent source of information on seizure lateralization, (2) it will provide information as to expected postoperative outcome, and (3) it may aid in appropriately selecting patients for invasive preoperative monitoring studies.

Surgical margins for excision of primary cutaneous squamous cell carcinoma.

Abstract: Background: No guidelines for the margin of resection of cutaneous squamous cell carcinoma have been based on data measuring subclinical tumor extension, as have been formulated for basal cell carcinoma. Objective and methods: Guidelines for appropriate margins of excision of primary cutaneous squamous cell carcinoma were formulated on the basis of a prospective study of subclinical microscopic tumor extension. Results: Four millimeter margins were adequate for most squamous cell carcinomas. However, certain tumor characteristics were associated with a greater risk of subclinical tumor extension and included size of 2 cm or larger, histologic grade 2 or higher, invasion of the subcutaneous tissue, and location in high-risk areas. Conclusion: Minimal margins of excision of 4 mm around the clinical borders of the squamous cell carcinoma are proposed for all but the high-risk tumors, in which at least a 6 mm margin is recommended.