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Biomedical subjects

R Marcus

Publications and source records attributed to R Marcus.

At least 19 recordsLinked to original sources
PubMed1992

Unusual presentation of common acute lymphoblastic leukemia antigen-positive extramedullary disease in childhood. Two patients with isolated masseter muscle involvement.

Two children with unusual extramedullary common acute lymphoblastic leukemia antigen (CALLA)-positive (CD10) disease are reported. Isolated masseter infiltration with CD10/CD19-positive lymphoblasts was present in both patients with no other evidence of disease. One child had relapse of common acute lymphoblastic leukemia, and the other had primary disease. Disease may have spread from lymph nodes overlying the masseter muscle. Immunophenotyping and immunogenotyping provided a rapid and accurate diagnosis for both children.

Child↗
PubMed1992

Percutaneous injuries during surgical procedures.

OBJECTIVE: To study the numbers and circumstances of percutaneous injuries (eg, needle sticks, cuts) that occur during surgical procedures. Surgical personnel risk infection with blood-borne pathogens from percutaneous injuries; some injuries might also place patients at risk by exposing them to a health care worker's blood. DESIGN: Observers present at 1382 surgical procedures recorded information about the procedure, the personnel present, and percutaneous injuries that occurred. SETTING: Four US teaching hospitals during 1990. PARTICIPANTS: Operating room personnel in five surgical specialties. MAIN OUTCOME MEASURES: Numbers and circumstances of percutaneous injuries among surgical personnel and instances in which surgical instruments that had injured a worker recontacted the patient's surgical wound. RESULTS: Ninety-nine injuries occurred during 95 (6.9%) of the 1382 procedures. Seventy-six injuries (77%) were caused by suture needles and affected the nondominant hand (62 injuries [63%]), especially the distal forefinger. The risk of injury adjusted for confounding variables by logistic regression was higher during vaginal hysterectomy (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.6 to 7.5) and lower during certain orthopedic procedures (OR, 0.2; CI, 0.1 to 0.7) than during 11 other types of procedures (reference group; OR, 1.0). Use of fingers rather than an instrument to hold the tissue being sutured was associated with 35 injuries (35%). Eighty-eight injuries (89%) were sustained by resident or attending surgeons; in 28 (32%) of the 88 injuries in surgeons, the sharp object that caused the injury recontacted the patient. CONCLUSION: Percutaneous injuries occur regularly during surgery, placing surgical personnel and, to a lesser extent, patients at risk for infection with blood-borne pathogens. Many such injuries may be preventable with changes in devices, techniques, or protective equipment; all such measures require careful evaluation to determine their efficacy in reducing injury and their effect on patient care.

Accidents, Occupational↗
PubMed1992

New approaches for interpreting projected bone densitometry data.

Bone densitometry using dual-photon absorptiometry (DPA) or dual-energy x-ray absorptiometry (DXA) has become a standard method for assessing bone mineral content in the spine and other skeletal regions. A projected areal density, referred to as bone mineral density (BMD,g/cm2), is normally calculated to assess regional bone density and strength. We demonstrate that this measure can be misleading when used to compare bones of different sizes due to inherent biases caused by bone thickness differences. For example, assuming that volumetric bone density remains constant and bony linear dimensions are proportional to height, a 20% increase in height would result in a 20% increase in both the thickness and the BMD of any bone. We describe new analysis methods to reduce the confounding effect of bone size, and we introduce a parameter, bone mineral apparent density (BMAD, g/cm3), that better reflects bone apparent density. Using this parameter, we calculate a quantity that serves as an index of bone strength (IBS, g2/cm4) for whole vertebral bodies. These analyses were applied to lumbar spine (L2-4) DXA measurements in a population of women 17-40 years old and appear to offer advantages to conventional techniques.

Absorptiometry, Photon↗
PubMed1992

Effects of resistance and endurance exercise on bone mineral status of young women: a randomized exercise intervention trial.

A substantial body of cross-sectional data and a smaller number of intervention trials generally justify optimism that regular physical activity benefits the skeleton. We conducted an 8 month controlled exercise trial in a group of healthy college women (mean age = 19.9 years) who were randomly assigned to a control group or to progressive training in jogging or weight lifting. We measured the following variables: bone mineral density (BMD) of the spine (L2-4) and right proximal femur using dual-energy x-ray absorptiometry, dynamic muscle strength using the 1-RM method, and endurance performance using the 1.5 mile walk/run field test. A total of 31 women completed the 8 month study. For women completing the study, compliance, defined as the percentage of workout sessions attended, was 97% for the runners (range 90-100%) and 92% (range 88-100%) for the weight trainers. Body weight increased by approximately 2 kg in all groups (p less than 0.05). Weight training was associated with significant increases (p less than 0.01) in muscle strength in all muscle groups. Improvement ranged from 10% for the deep back to 54% for the leg. No significant changes in strength scores were observed in the control or running groups. Aerobic performance improved only in the running group (16%, p less than 0.01). Lumbar BMD increased (p less than 0.05) in both runners (1.3 +/- 1.6%) and weight trainers (1.2 +/- 1.8%). These results did not differ from each other but were both significantly greater than results in control subjects, in whom bone mineral did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

Bone mineral density, muscle strength, and recreational exercise in men.

Muscle strength has been shown to predict bone mineral density (BMD) in women. We examined this relationship in 50 healthy men who ranged in age from 28 to 51 years (average 38.3 years). BMD of the lumbar spine, proximal femur, whole body, and tibia were measured by dual-energy x-ray absorptiometry (Hologic QDR 1000W). Dynamic strength using one repetition maximum was assessed for the biceps, quadriceps, and back extensors and for the hip abductors, adductors, and flexors. Isometric grip strength was measured by dynamometry. Daily walking mileage was assessed by 9 week stepmeter records and kinematic analysis of video filming. Subjects were designated as exercisers and nonexercisers. Exercisers participated in recreational exercise at least two times each week. The results demonstrated that BMD at all sites correlated with back and biceps strength (p < 0.01 to p = 0.0001). Body weight correlated with tibia and whole-body BMD (p < 0.001); age negatively correlated with Ward's triangle BMD (p < 0.01). In stepwise multiple regressions, back strength was the only independent predictor of spine and femoral neck density (R2 = 0.27). Further, back strength was the most robust predictor of BMD at the trochanter, Ward's triangle, whole body, and tibia, although biceps strength, age, body weight, and leg strength contributed significantly to BMD at these skeletal sites, accounting for 35-52% of the variance in BMD. Exercisers and nonexercisers were similar for walking (3.97 versus 3.94 miles/day), age (37.8 versus 38.5) years, and weight (80.0 versus 77.7 kg). However, BMD and muscle strength were significantly greater in exercises than in nonexercisers.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

In vivo assessment of forearm bone mass and ulnar bending stiffness in healthy men.

The cross-sectional bending stiffness EI of the ulna was measured in vivo by mechanical resistance tissue analysis (MRTA) in 90 men aged 19-89 years. MRTA measures the impedance response of low-frequency vibrations to determine EI, which is a reflection of elastic modulus E and moment of inertia I for the whole ulna. EI was compared to conventional estimates of bone mineral content (BMC), bone width (BW), and BMC/BW, which were all measured by single-photon absorptiometry. Results obtained from the nondominant ulna indicate that BW increases (r = 0.27, p = 0.01) and ulnar BMC/BW decreases (r = -0.31, p < or = 0.005) with age. Neither BMC nor EI declined with age. The single best predictor of EI was BW (r2 = 0.47, p = 0.0001), and further small but significant contributions were made by BMC (r2 = 0.53, p = 0.0001) and grip strength (r2 = 0.55, p = 0.0001). These results suggest that the resistance of older men to forearm fracture is related to age-associated changes in the moment of inertia achieved by redistributing bone mineral farther from the bending axis. We conclude that the in vivo assessment of bone geometry offers important insights to the comprehensive evaluation of bone strength.

Absorptiometry, Photon↗
PubMed1992

Treatment of myelodysplastic syndromes (MDS) and high leukaemic risk with low-dose cytosine arabinoside (LD-AraC) plus granulocyte-macrophage colony-stimulating factor (rh GM-CSF). The EORTC Leukaemia Group.

Symptomatic patients with myelodysplastic syndromes (MDS) and 10-30% blasts in the bone marrow were treated with low-dose AraC (2 x 10 mg/m2 subcutaneously (sc) days 1-14) and GM-CSF (fully glycosylated, Sandoz/Schering-Plough, 2 x 150 micrograms protein/day sc) given either subsequently (days 15-21) or simultaneously (days 8-14 and one week rest). Evaluations were carried out after three courses (nine weeks); responding patients could be continued for two further cycles. Eighty-two patients with refractory anaemia and excess of blasts (RAEB), with (RAEBt) or without transformation, were evaluable: 45 RAEB and 37 RAEBt, mean age 64 years (range 17-80 years). A complete remission was achieved in 14 cases (17%), 11 had a good response (13%), and 12 a partial response (15%). Stable disease was found in 21 cases (26%). There were 12 cases of toxic death (15%), progression was noted in eight patients (10%), and death due to disease in three (4%). No difference existed between the two treatment arms with respect to response. Major adverse events during treatment were haemorrhage (25%), infections (23%), and fever with GM-CSF (21%). GM-CSF did not induce leukaemia nor contribute to haemorrhage induced by AraC, but gave rise to an overall response rate of 46% which is high and relatively durable as compared to other treatments in this disease.

Acute Disease↗
PubMed1992

Complex chromosomal rearrangements in an unusual variant of hairy cell leukemia.

An unusual case of variant HCL with multiple ribosomal lamellar complexes and complex chromosomal changes is described. The karyotype of the main cell clone is characterized by involvement of chromosome 5 at q13.3 and interstitial deletion of 7q. However, there is no other evidence of myelodysplasia and the abnormal cells are of lymphoid origin with a B-cell immunophenotype. The clonal chromosomal evolution involves rearrangements at sites known to be specifically altered in lymphoid tumors.

Aged↗
PubMed1992

Effects of conjugated estrogen on the calcitriol response to parathyroid hormone in postmenopausal women.

We evaluated the effects of estrogen on the calcitriol response to the active peptide, human PTH(1-34), in postmenopausal women. Fifteen women were studied before and again after at least 1 month of treatment with conjugated equine estrogens, 1.25 mg/day. Six women received two series of four graded peptide infusions, each with the sequence 200, 400, 800, and 1600 USP U hPTH(1-34). Nine women received only one dose of peptide, either 200 or 800 U, before and while taking estrogen. Baseline values and the incremental and percent changes in circulating calcitriol 24 h after the 20-min infusions were evaluated. Estrogen treatment resulted in significant reductions in blood levels of calcium (2.26 +/- 0.03 mmol/L vs. 2.16 +/- 0.02, P less than 0.05) and phosphorus (1.23 +/- .05 mmol/L vs. 1.14 +/- 0.03, P less than 0.005), a rise in serum calcitriol concentrations (42.2 +/- 3.9 pg/mL vs. 28.6 +/- 3.1, P less than 0.005), and no change in circulating PTH. The rise in calcitriol after 200 U hPTH(1-34) was significantly greater on estrogen (17.6 +/- 2.0 pg/mL vs. 9.5 +/- 1.8, P less than 0.01), but estrogen did not alter incremental responses to larger doses. When results were normalized for differences in baseline values, the estrogen-related change in response to 200 U was no longer significant. hPTH(1-34) acutely increased urinary clearance of cAMP and phosphorus, but estrogen did not affect this response. We conclude that exogenous estrogen does not increase renal sensitivity to PTH in postmenopausal women.

Calcitriol↗
PubMed1992

Age-dependent effect of resistance exercise on growth hormone secretion in people.

We measured serum GH responses to a standardized circuit of resistance exercise in 12 young subjects (6 men and 6 women; 27 +/- 1.6 yr old) and in 11 elders (6 men and 5 women; 72 +/- 0.8 yr old). Initial assessment of strength [1 repetition maximum (1RM)] was made of 12 muscle groups using Nautilus equipment. One week later, subjects carried out the exercise protocol, 3 sets of 8 repetitions for each of the 12 exercises, at 70% of predetermined 1RM values. Venous blood was drawn at baseline, after each exercise, and every 2 min during 10 min of recovery. In young subjects serum immunoreactive GH rose by completion of the second exercise, increased and remained elevated through the remainder of the exercise period, and decreased toward baseline by 10 min of recovery. In the elderly subjects, baseline GH values were similar to those in the young (1.76 +/- 0.41 vs. 2.61 +/- 0.73 micrograms/L) and did not increase above 6 micrograms/L at any time during or after exercise. Exercise increased GH in both groups, but peak values (14.9 +/- 3.5 micrograms/L in young; 2.44 +/- 0.6 micrograms/L in old) and integrated (198 +/- 47 in young; 37.8 +/- 0.8 in old) were significantly greater in the young subjects (P less than 0.05). GH responses showed no gender difference in either group. Brief increases in pulse rate were observed during individual exercises, but sustained elevations did not occur. To assess the effect of exercise intensity on GH response, we compared responses to exercise at 70% and 85% of 1RM in 7 young and 11 older people. In the young subjects, GH responses were nonsignificant at 60% and increased progressively at 70% and 85% of 1RM. No significant effect of exercise intensity was observed in the older subjects. We conclude that resistance exercise promptly elevates circulating GH concentrations in healthy young adults. This response is related to the intensity of the resistance stimulus, although a small contribution of aerobic stress cannot be excluded. The GH response to resistance activity is grossly diminished in healthy elderly men and women.

Adult↗
PubMed1992

The pre-ulcerative phase of carrageenan-induced colonic ulceration in the guinea-pig.

The pre-ulcerative phase of carrageenan-induced colonic ulceration was investigated in guinea-pigs supplied 3% degraded carrageenan as an aqueous solution as drinking fluid for 2 or 3 days during which no ulceration of the bowel was observed with the naked eye or dissecting microscope. Mucosal microscopic changes, from caecum to rectum, were multifocal and included cellular infiltrates, dilatation of glands, crypt abscesses, micro-ulcers and sulphated polysaccharide in the lamina propria. Sulphated polysaccharide was also demonstrated histologically for the first time within the surface epithelium and showed ultrastructural features similar to carrageenan. The results indicate that colonic epithelium in the guinea-pig is capable of macromolecular absorption. Carrageenan, a highly active polyanionic electrolyte, within the surface epithelial cells is most likely a primary factor in the breakdown of mucosal integrity. Macromolecular absorption causing enteropathy of the large bowel is a new pathophysiological concept which may have implications in man, particularly in the pathology of large bowel disease.

Animals↗
PubMed1992

Multiple primary cutaneous plasmacytomas.

BACKGROUND: Cutaneous plasmacytoma is an uncommon tumor and is mostly seen in the context of end-stage multiple myeloma. Only 20 cases of primary cutaneous plasmacytoma have been documented. A significant proportion of these patients went on to develop systemic disease with a poor prognosis. In a number of patients, however, the abnormal clone of plasma cells may arise in the skin and never progress to multiple myeloma involving the bone marrow. OBSERVATIONS: We describe a patient who developed multiple primary cutaneous plasmacytomas after a possible insect bite reaction. The monoclonality of the tumor cells is demonstrated using immunohistochemical techniques. He has been treated vigorously with chemotherapy and local radiotherapy and remains well 3 years after diagnosis. Bone marrow has been harvested for use as an autologous bone marrow transplant in the event of systemic relapse. CONCLUSIONS: Unlike previous reports of this rare entity, this case documents the monoclonality of tissue plasma cells with immunohistochemical techniques. As cutaneous plasmacytomas have been reported with an early significant mortality, unlike extramedullary plasmacytomas elsewhere, we have advocated combination chemotherapy and cryopreservation of uninvolved bone marrow for future autologous bone marrow transplantation should systemic myelomatosis develop in the patient.

Adult↗
PubMed1991

Growth hormone therapy in hypophosphatemic rickets.

The effects of growth hormone therapy on the biochemical measures of bone metabolism were studied in 11 children aged 3.5 to 17 years who had familial hypophosphatemic rickets; five were male. Subjects were maintained on a regimen of stable doses of conventional therapy (calcitriol and phosphate). Subjects were studied at baseline receiving conventional therapy and during three sequential treatment periods: no therapy (4 weeks), growth hormone only (0.05 mg/kg per day for 4 weeks), and conventional therapy plus growth hormone (2 weeks). The nine youngest subjects were continued on a regimen of triple therapy for an additional 24 weeks. Serum phosphate averaged 0.93 +/- 0.13 mmol/L (mean +/- SD) at entry and decreased when the subjects were not receiving any therapy. During the 4 weeks of growth hormone only treatment, phosphate rose in all 11 subjects (0.70 +/- 0.08 mmol/L to 0.83 +/- 0.08 mmol/L). With triple therapy, phosphate remained higher than with no therapy. Calcitriol, osteocalcin, and parathyroid hormone increased as the subjects received growth hormone alone. Insulinlike growth factor I z scores rose significantly in response to growth hormone therapy alone. All nine subjects receiving 6 months of triple therapy increased their growth rate z scores. Exogenous growth hormone therapy may be useful in familial hypophosphatemic rickets.

Adolescent↗
PubMed1991

Noninvasive assessment of ulnar bending stiffness in women.

The load-carrying capacity of cortical bone is closely related to its geometry and to its fundamental material properties, including mineral content (BMC). Together these determine the bending stiffness EI, where I is the cross-sectional moment of inertia and E is Young's modulus of elasticity. To assess the relationship of BMC and bone width (BW) to EI in healthy women, we used mechanical response tissue analysis (MRTA), a noninvasive method that involves analysis of tissue responses to ulnar vibration. A total of 48 healthy women were enrolled into an older (64 +/- 1y, n = 25) and a younger (25 +/- 0.6y, n = 23) group. BMC and BW of the dominant ulna were measured by single-photon absorptiometry (SPA). EI was determined by MRTA. BMC (0.75 +/- 0.02 versus 0.63 +/- 0.02 g/cm), BMC/BW (0.75 +/- 0.02 versus 0.63 +/- 0.02 g/cm2), and EI (27.7 +/- 1.3 versus 21.3 +/- 1.1 N.m2) were significantly greater (p less than 0.005) in the young subjects. BW did not change with age (1.00 +/- 0.01 versus 1.01 +/- 0.01 cm). In young women, simple correlations of BMC and BW with EI were both significant. By multiple regression analysis only BW independently predicted EI (EI = -0.35 + 39.1 x BMC, R2 = 0.52). In older women BMC and BW correlated with EI, but in multiple regression only BMC was significant (EI = -34.5 + 62.1 x BW; R2 = 0.45). When this analysis of older women included only those whose BMC values were within 2 SD of the young mean, BMC remained the only significant predictor of EI.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1991

Effects of voluntary exercise on bone mineral content in rats.

We used a voluntary running model to explore the relationship between average daily running distance and bone mineral status of rats. A total of 60 male Sprague-Dawley rats were randomly assigned at 6 weeks of age to a sedentary control group (n = 22) or to a group with unlimited access to a running wheel (n = 38). The running distance of exercising rats was monitored daily, and steady-state running levels ranged from 3.2 to 18.1 km/day. At the end of the experimental period, femora and tibiae were dissected and bone mineral content (BMC, g/cm) and bone mineral density (BMD, g/cm2) were measured by single-photon absorptiometry. Cross-sectional morphometry was examined by taking a transverse section of the femoral middiaphysis. Hindlimb percentage fat was significantly higher in controls than in runners (20.0 +/- 1.2 versus 11.1 +/- 0.6, p less than 0.001), and soleus mass was greater in runners than in controls (371 +/- 8.1 versus 320 +/- 0.8 mg, p less than 0.001). Femoral and tibial lengths, weights, and volumes were significantly higher in runners than in controls (p less than 0.005). BMC and BMD were higher in runners than in controls at all sites apart from the distal femur. Cross-sectional areas at the femoral midshaft were greater in running rats than in sedentary controls (6.26 +/- 0.1 versus 5.45 +/- 0.3 mm2, p less than 0.02), as was the polar moment of inertia (15.6 +/- 0.6 versus 12.7 +/- 0.2 mm4, p less than 0.05). No positive correlation was found between distance run and BMC, BMD, cross-sectional area, or polar moment of inertia.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1991

Estrogens and progestins in the management of primary hyperparathyroidism.

One of the common dilemmas in clinical endocrine practice is the management of patients with hyperparathyroidism (HPT) who either cannot or will not undertake definitive surgical treatment. Therapeutic decisions would be simplified by the availability of a nonsurgical approach to control biochemical abnormalities and forestall the consequences of this condition. In the short term, oral phosphorus salts can be safe and effective. For chronic therapy, only estrogens and progestins have been examined in sufficient detail to merit discussion. Estrogens normalize serum and urinary calcium in the majority of older women with HPT. Biochemical control is generally maintained for as long as patients continue treatment. The data support the view that estrogen inhibits the actions of PTH, particularly on bone, but does not reduce the abnormal PTH secretion. Androgenic progestins may also lower serum and urinary calcium in HPT, but current data suggest that normalization of serum calcium levels is more likely to occur with estrogen. Although reduction in urinary calcium excretion should prove effective in preventing nephrolithiasis, it is unclear whether hormone therapy provides protection against fracture. Whether or not hormone replacement is prescribed, nonsurgical management requires a highly committed patient who is willing to undergo extensive and prolonged follow-up.

Administration, Oral↗