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Biomedical subjects

G W Modin

Publications and source records attributed to G W Modin.

15 recordsLinked to original sources
PubMed2003

Daily treatment with parathyroid hormone is associated with an increase in vertebral cross-sectional area in postmenopausal women with glucocorticoid-induced osteoporosis.

Daily treatment with hPTH (1-34) is associated with a significant increase in bone formation which results in large gains in lumbar spine bone mass. However, bone formation is known to occur on trabecular, endocortical and periosteal surfaces. The purpose of this study was to determine whether daily treatment with hPTH (1-34) for 1 year was associated with a change in vertebral cross-sectional area, or vertebral size, as measured by serial quantitative computed tomography scans. Fifty-one postmenopausal women treated chronically with both glucocorticoids and hormone replacement therapy (HRT) were randomized to either daily hPTH (1-34) for 1 year and HRT or to a control group treated with only HRT. Measurements of bone density of the spine were obtained every 6 months by dual-energy X-ray absorptiometry (DXA) and annually by QCT of the L1 and L2 vertebrae. Vertebral cross-sectional area (VCSA) was obtained from the QCT scans. In addition, we estimated the vertebral compressive strength (VSFOM, g(2)/cm(4) = trabecular BMD(2) x VCSA). After 1 year of hPTH (1-34) treatment, VCSA increased 4.8% (p < 0.001), and 1 year after treatment was discontinued VCSA was still 2.6% higher than the baseline value (p < 0.05). The control group had no change in VCSA. In addition, estimated vertebral compressive strength increased more than 200% over baseline levels in the hPTH (1-34) treatment group and no change was observed in the control group. In summary, daily treatment with hPTH (1-34) for 1 year increased vertebral size as measured by VCSA and this increase was maintained after hPTH (1-34) was discontinued. Since vertebral fracture risk is related to both bone size and bone mass, we cautiously speculate that the increase in vertebral size associated with hPTH (1-34) treatment is at least partially responsible for increased vertebral bone strength and reduction of fracture risk associated with this therapy in postmenopausal osteoporosis.

Absorptiometry, Photon↗
PubMed2001

Atypical right atrial flutter patterns.

BACKGROUND: The purpose of our study was to define the incidence and mechanisms of atypical right atrial flutter. METHODS AND RESULTS: A total of 28 (8%) of 372 consecutive patients with atrial flutter (AFL) had 36 episodes of sustained atypical right AFL. Among 24 (67%) of 36 episodes of lower loop reentry (LLR), 13 (54%) of 24 episodes had early breakthrough at the lower lateral tricuspid annulus, whereas 11 (46%) of 24 episodes had early breakthrough at the high lateral tricuspid annulus, and 9 (38%) of 24 episodes showed multiple annular breaks. Bidirectional isthmus block resulted in elimination of LLR. A pattern of posterior breakthrough from the eustachian ridge to the septum was observed in 4 (14%) of 28 patients. Upper loop reentry was observed in 8 (22%) of 36 episodes and was defined as showing a clockwise orientation with early annular break and wave-front collision over the isthmus. Two patients had atypical right AFL around low voltage areas ("scars") in the posterolateral right atrium. CONCLUSIONS: Atypical right AFL is most commonly associated with an isthmus-dependent mechanism (ie, LLR or subeustachian isthmus breaks). Non-isthmus-dependent circuits include upper loop reentry or scar-related circuits.

Aged↗
PubMed2000

Quantitative effects of functional bundle branch block in patients with atrioventricular reentrant tachycardia.

Changes in the retrograde conduction time (ventriculoatrial [VA]) interval during functional bundle branch block (BBB) have been used to separate septal from free wall accessory pathways (APs), but different values of the VA interval prolongation (deltaVA) have been described in different reports. A total of 95 patients with single nondecremental APs who developed BBB during atrioventricular reentrant tachycardia were studied. Free wall APs were found in 60 patients, and 35 had septal APs. For patients with free wall APs, complete and incomplete BBB ipsilateral to the atrial insertion site of APs were observed in 39 of 60 patients (65%) and 31 of 60 patients (52%), respectively. For patients who had both complete (QRS > or = 120 ms) and incomplete (QRS <120 ms) BBB during atrioventricular reentrant tachycardia, deltaVA for patients with complete BBB was significantly greater than in those with incomplete BBB, 59 +/- 19 ms versus 30 +/- 11 ms, p <0.001. For patients with septal APs and complete and incomplete BBB during tachycardia, the mean deltaVA for those with complete BBB was 31 +/- 20 ms and was significantly longer than in patients with incomplete BBB (14 +/- 6 ms), p <0.001. There was no significant difference in deltaVA between those with free wall APs and incomplete BBB compared with those with septal APs and complete BBB. The criteria of QRS > or = 120 ms associated with deltaVA > or =40 ms served to best separate free wall from septal APs with a sensitivity of 88% and a specificity of 89%. Left anterior fascicular block was associated with marked lengthening of deltaVA for those with left free wall APs, whereas a left posterior fascicular block pattern resulted in a marked increase in the deltaVA for patients with posteroseptal APs. In the absence of fascicular block patterns, a deltaVA > or =40 ms provides strong evidence of a free wall AP, with a sensitivity of 95% and a specificity of 100%. The left posterior fascicle appears to provide predominant innervation of the posterior septum.

Adolescent↗
PubMed2000

Bone mass continues to increase at the hip after parathyroid hormone treatment is discontinued in glucocorticoid-induced osteoporosis: results of a randomized controlled clinical trial.

Glucocorticoid-induced osteoporosis is the most common secondary cause of osteoporosis. In this 24-month study, we report changes in bone turnover and bone mass after 12 months of daily injections of human parathyroid hormone 1-34 [hPTH(1-34)] and 12 months off treatment in postmenopausal women (mean age, 63 years) with osteoporosis treated with glucocorticoid and hormone replacement therapy. Response to the treatment was assessed with bone mineral density (BMD) measurements of the lumbar spine by quantitative computed tomography (QCT); BMD measurements of the lumbar spine, hip, and forearm by dual-energy X-ray absorptiometry (DXA); and biochemical markers of bone turnover. The mean (+/-SEM) change in BMD of the lumbar spine by QCT and DXA in the PTH group at 24 months was 45.9+/-6.4% and 12.6+/-2.2% (p < 0.001). The change in total hip and femoral neck BMD was not significant at 12 months but increased to 4.7+/-0.9% (p < 0.01) and 5.2+/-1.3% at 24 months, respectively, as compared with a relatively small change of 1.3+/-0.9% and 2.6+/-1.7% in the estrogen-only group. The mean percent differences in BMD of the lumbar spine by QCT and DXA between the groups at 24 months were 43.1% and 11.9%, respectively (p < 0.001). The mean percent differences over the estrogen-only group in hip BMD were 3.4% for total hip (p < 0.01) and 2.6% for femoral neck at 24 months. Biochemical markers of bone turnover increased to more than 150% during the first 6 months of therapy, remained elevated throughout the 12-month treatment period, and returned to baseline values within 6 months of discontinuing the PTH treatment. These results suggest that PTH dramatically increases bone mass in the lumbar spine and hip in postmenopausal women with glucocorticoid-induced osteoporosis who are taking hormone replacement therapy. However, the maximum effect of this anabolic agent on bone mass at the hip after 12 months of treatment requires at least 6-12 months after the PTH treatment is discontinued.

Absorptiometry, Photon↗
PubMed1999

Prevention of glucocorticoid-induced osteoporosis: provider practice at an urban county hospital.

PURPOSE: We sought to determine the frequency and types of prophylaxis for osteoporosis that were prescribed to outpatients who were receiving chronic glucocorticoid treatment and to identify the patient and provider characteristics that were associated with the use of prophylaxis. SUBJECTS AND METHODS: We identified 215 adult outpatients at San Francisco General Hospital who had received a prescription for prednisone (or its equivalent) at a daily dose of at least 5 mg for at least 1 month. Patient demographic characteristics, the diagnosis for which glucocorticoids were prescribed, comorbid illnesses, and medications were determined by chart review. Characteristics of the patients who were prescribed prophylaxis were compared with those of patients who were not prescribed prophylaxis. RESULTS: Prophylaxis for glucocorticoid-induced osteoporosis was prescribed to 58% of patients. Patients prescribed prophylaxis were older (mean [+/-SD] age of 50.0 +/- 13.9 versus 44.5 +/- 13.6 years, P = 0.004), more likely to be female (69% versus 40%, P <0.0001), postmenopausal if female (84% versus 56%, P = 0.002), have more comorbid illnesses (63% versus 29%, P = 0.001), and take multiple medications (66% versus 45%, P = 0.002). Patients attending the rheumatology clinic were 1.6 times more likely to receive prophylaxis than those attending other clinics (P <0.0001). The strongest predictor of prophylaxis was postmenopausal state. In premenopausal women, the independent predictors of prophylaxis were being treated in the rheumatology clinic and the presence of comorbid illnesses, whereas comorbid illnesses was the only independent predictor of prophylaxis in men. CONCLUSIONS: Educational efforts should be directed toward increasing awareness of the importance of glucocorticoid-induced osteoporosis and its prevention.

Adult↗
PubMed1998

Parathyroid hormone treatment can reverse corticosteroid-induced osteoporosis. Results of a randomized controlled clinical trial.

Corticosteroid-induced osteoporosis is the most common secondary cause of osteoporosis. We conducted a 12-mo, randomized clinical trial of human parathyroid hormone 1-34 (hPTH 1-34) in postmenopausal women (mean age was 63 yr) with osteoporosis who were taking corticosteroids and hormone replacement therapy. Response to the treatment was assessed with bone mineral density (BMD) measurements of the lumbar spine by quantitative computed tomography (QCT); BMD measurements of the lumbar spine, hip, and forearm by dual-energy x-ray absorptiometry (DXA); and biochemical markers of bone turnover. The mean (+/-SE) changes in BMD of the lumbar spine by QCT and DXA in the PTH group were 35+/-5.5% and 11+/-1.4%, respectively, compared with a relatively small change of 1.7+/-1.8% and 0+/-0.9% in the estrogen-only group. The differences in mean percentage between the groups at 1 yr were 33.5% for the lumbar spine by QCT (P < 0.001) and 9.8% for the lumbar spine by DXA (P < 0.001). The changes in the hip and forearm were not significantly different between or within the groups. During the first 3 mo of PTH treatment, markers of bone formation increased to nearly 150%, whereas markers of bone resorption increased only 100%, suggesting an early uncoupling of bone turnover in favor of formation. These results suggest that parathyroid hormone dramatically increases bone mass in the central skeleton of postmenopausal women with corticosteroid- induced osteoporosis who are taking hormone replacement.

Absorptiometry, Photon↗
PubMed1997

Not all postmenopausal women on chronic steroid and estrogen treatment are osteoporotic: predictors of bone mineral density.

Chronic steroid use results in osteoporosis, and postmenopausal women are believed to be at a high risk for steroid-induced bone loss. The purpose of this study was to determine predictors of bone mineral density (BMD) in postmenopausal women on both chronic steroid and hormone replacement therapy. Seventy-six postmenopausal women (> or = 3 years postmenopausal, > or = 2 years of steroid treatment of > or = 5 mg/day of prednisone, and > or 1 year of hormone replacement therapy) were recruited into this study. Measurements of BMD of the lumbar spine and femoral neck were obtained in all subjects. Risk factors for osteoporosis were obtained by questionnaire. Discriminant analysis was performed to determine predictors of BMD. Osteoporosis, defined by a T score of < -2.5, was present in the lumbar spine or femoral neck in 34 of the 76 subjects. Based on these criteria, women with osteoporosis were significantly older, were more years postmenopausal, and had a lower body mass index (BMI) than women who did not have osteoporosis. Predictors of osteoporosis for both the femoral neck and spine included a low BMI (P < 0.05), more years postmenopausal (P < 0.01), and more years on steroids (P < 0.01). Low BMI was the only significant predictor of osteoporosis in the lumbar spine (P < 0.05), whereas for the femoral neck both years on steroids (P < 0.05) and BMI (P < 0.05) were significant predictors of low BMD. In summary, not all postmenopausal women on chronic steroid and hormone replacement therapy are osteoporotic but a low BMI, more years on steroids, and more years postmenopausal were significant predictors of osteoporosis in these subjects.

Absorptiometry, Photon↗
PubMed1995

Identification of patients with acute lung injury. Predictors of mortality.

A recent North-American-European Consensus Conference proposed new, uniform criteria for the definition of acute lung injury, in part to facilitate earlier identification of patients for clinical trials. However, these criteria have not been evaluated prospectively. We designed a prospective cohort study of 123 consecutive patients with acute lung injury prospectively identified on admission to the adult intensive care units of a tertiary care university hospital. The objectives were to determine if selection of patients using the new criteria for acute lung injury results in a significant change in the clinical characteristics, risk factors, or predictors of mortality when compared with prior studies of patients with adult respiratory distress syndrome (ARDS); and to determine if a quantitative index of the severity of acute lung injury has prognostic value in identifying nonsurvivors of acute lung injury. We used three methods: (1) prospective identification of patients with acute lung injury using a PaO2/FIO2 ratio < 300 and bilateral infiltrates on chest radiograph in the absence of left heart failure; (2) evaluation of the severity of lung injury using a four-point scoring system; and (3) stepwise logistic regression analysis to identify variables significantly associated with hospital mortality. Overall hospital mortality was 58%. Sepsis was the most common clinical disorder (50/123 or 41%) associated with the development of acute lung injury. Using the new definition for acute lung injury, 66 of the 123 patients were enrolled with a PaO2/FIO2 ratio between 150 and 299; 57 of the 123 patients had a PaO2/FIO2 < 150 at the time of entry into the study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

New algorithm for the localization of accessory atrioventricular connections using a baseline electrocardiogram.

OBJECTIVES: In this study, we propose a new algorithm for accessory atrioventricular pathway localization using a 12-lead electrocardiogram (ECG). BACKGROUND: Radiofrequency catheter ablation produces a very discrete lesion, and ECG localization based on surgical dissection is obsolete. METHODS: Stepwise discriminant analysis was used to assess the relation of 18 pre-excited ECG (QRS duration > 100 ms) variables to the site of successful ablation in 93 patients. The most discriminating variables were combined to form rules for each location. The ECGs were retested by these rules to determine predictive accuracy. RESULTS: If the precordial QRS transition was at or before lead V1, the pathway had been ablated on the left side. If it was after lead V2, the pathway had been ablated on the right side. If the QRS transition was between leads V1 and V2 or at lead V2, then if the R wave amplitude in lead I was greater than the S wave by > or = 1.0 mV, it was right-sided; otherwise, it was left-sided (p < 0.0001, sensitivity 100%, specificity 97%). Right-side pathways. If the QRS transition was between leads V2 and V3, the pathway was right septal; if after lead V4, it was right lateral. If it was between leads V3 and V4, then if the delta wave amplitude in lead II was > or = 1.0 mV, it was right septal; otherwise, it was right lateral (p < 0.0001, sensitivity 97%, specificity 95%). In right lateral locations, if the delta wave frontal axis was > or = 0 degrees, or if it was < 0 degrees but the R wave amplitude in lead III was > or = 0 mV, it was anterolateral; otherwise, it was posterolateral (p < 0.0001, sensitivity 100%, specificity 87.3%). Anteroseptal pathways had a sum of delta wave polarities in leads II, III and aVF > or = +2(p < 0.0001, sensitivity 100%, specificity 100%). Posteroseptal pathways (inferior delta wave sum < or = -2) were less well discriminated from right midseptal pathways (inferior delta wave sum < or = 1 > or = -1) (p < 0.0001, sensitivity 76.5%, specificity 71%) [corrected]. Left-sided pathways. Two or more positive delta waves in the inferior leads or the presence of an S wave amplitude in lead aVL greater than the R wave, or both, discriminated left anterolateral pathways from posterior pathways (p < 0.001, sensitivity and specificity 100%). If the R wave in lead I was greater than the S wave by > or = 0.8 mV, and the sum of inferior delta wave polarities was negative, the location was posteroseptal; otherwise, it was posterolateral (p < 0.05, sensitivity 71.4%, specificity 100%). CONCLUSIONS: Using the algorithm derived, a right-sided accessory pathway can be reliably distinguished from one that is left-sided, right free wall from right septal, right anterolateral from posterolateral and anteroseptal from other right septal pathways. Left anterolateral pathways can be distinguished from left posterior pathways and left posterolateral pathways from left posteroseptal pathways.

Algorithms↗
PubMed1993

Transfusion significantly increases the risk for infection after splenic injury.

OBJECTIVES: To determine if splenectomy results in an increased risk for perioperative infection when analyzed against splenic repair and to identify factors associated with perioperative infection, respiratory complication, and admission to the intensive care unit following surgery for splenic trauma. DESIGN: Data were collected retrospectively from hospital records and analyzed using stepwise multiple logistic regression. SETTING: San Francisco (Calif) General Hospital, an urban level 1 trauma center. PATIENTS: All patients (n = 252) undergoing operation for traumatic splenic injury at San Francisco General Hospital from 1984 through 1990. Patients who died within 24 hours of presentation were excluded from the study. MAIN OUTCOME MEASURES: Perioperative infection, respiratory complications, and admission to the intensive care unit. RESULTS: Infection rates and the types of organisms yielded in cultures were similar between patients who underwent splenectomy and repair. Gram-negative and gram-positive organisms were found in equal numbers, and in no group did encapsulated organisms predominate. Splenectomy had no independent impact on any of the three outcome measures. Total blood transfusion was found to be the only independently significant variable associated with perioperative infection and respiratory complication. Total blood transfusion of more than 2 U and Injury Severity Score of greater than 25 were independently significantly associated with admission to the intensive care unit. CONCLUSIONS: The choice between splenectomy and splenic repair does not affect the risk for perioperative infection following injury, whereas blood transfusion significantly increases the risk for perioperative infection, respiratory complication, and admission to the intensive care unit.

Adult↗
PubMed1991

Natural history of disseminated Mycobacterium avium complex infection in AIDS.

This study sought to better characterize the natural history of AIDS-associated disseminated Mycobacterium avium complex (MAC) infection. Towards that end two retrospective studies were done: a case-control survival study and a MAC respiratory colonization study. Among 137 consecutive patients who had a sterile body site cultured for mycobacteria within 3 months of their first AIDS-defining episode of Pneumocystis carinii pneumonia, median survival was significantly shorter in those with disseminated MAC infection (107 days; 95% confidence interval [CI] 55-179) than those with negative cultures (275 days; 95% CI 230-318; P less than .01), even after controlling for age, absolute lymphocyte count, and hemoglobin concentration. Among 34 patients with AIDS and respiratory MAC colonization, 22 later developed disseminated infection (65% predictive value for subsequent MAC dissemination). Disseminated MAC infection was associated with significantly shorter survival for patients with AIDS, and the presence of MAC in respiratory specimens has substantial predictive value for subsequent disseminated infection.

Acquired Immunodeficiency Syndrome↗
PubMed1987

Coronary artery bypass graft patency: noninvasive evaluation with MR imaging.

A noninvasive means of determining coronary artery bypass graft (CABG) patency in symptomatic patients would be an important clinical asset. The accuracy of magnetic resonance (MR) imaging was evaluated for this purpose. Multiphasic electrocardiographically gated MR imaging examinations were performed in 25 patients with a total of 72 grafts. Transverse images of the heart at ten anatomic levels were obtained at five or six phases of the cardiac cycle. The MR images were read blindly to determine CABG patency versus occlusion, and these results were compared with those of coronary angiography performed within 2 months before the MR imaging. MR imaging correctly disclosed 43 patent grafts and 13 occluded grafts (predictive accuracy, 78%). Patency and occlusion were incorrectly diagnosed from MR imaging findings in five and four CABGs, respectively. CABG status could not be determined in seven (10%) grafts because the grafts were visualized at only one anatomic level. Thus, the accuracy of a definitive MR imaging evaluation was 91% (43 of 47 grafts) for patency determination and 72% (13 of 18 grafts) for occlusion determination. MR imaging appears to be a useful method for the noninvasive evaluation of CABGs.

Adult↗
PubMed1986

A rapid method of theophylline assay in the physician's office.

A competitive fluorescent enzyme immunoassay for theophylline is described which employs a theophylline monoclonal antibody. Fifty-two samples were assayed by this method and by high pressure liquid chromatography. The coefficient of correlation contrasting the methods equaled 0.979. The coefficient of determination was 0.959. The standard error of the correlation coefficient was 1.392. The bias of the immunoassay method versus high pressure liquid chromatography was 0.8 with 95% confidence limits of 0.4 to 1.2. In the same 52 patients, the precision of 1.6 with 95% confidence limits of 1.3 to 1.9 was obtained. There are numerous advantages of this new method compared with high pressure liquid chromatography. For the practicing physician, the rapid immunoassay for theophylline described here is proper for office application.

Asthma↗
PubMed1984

Antigen recognition in Chinese and Caucasians.

Five hundred ninety-two allergic subjects from two different groups (Caucasian and Chinese) were skin tested to detect sensitivity to grass and tree pollens. Chinese reacted five times more often to trees than Caucasians. Chinese were 2.3 times more likely to be sensitive to grass pollens than were Caucasians (P less than .01). In both groups, subjects sensitive to grass pollens were more likely to be sensitive to tree pollens (P less than .001 for both populations). Grass sensitive Chinese were 21.7 times more likely to react to trees than those not grass sensitive. Grass sensitive Chinese were 10.8 times more likely to be sensitive to trees than Caucasians. Several hypotheses are presented to explain these results. This if the first report of a racial difference in antigen recognition. Physicians who test and treat Chinese patients with allergies may wish to more carefully evaluate the possible role of cedar, cypress, and juniper in their patients' allergic condition.

Adolescent↗