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Biomedical subjects

R Marcus

Publications and source records attributed to R Marcus.

At least 217 records · Page 12Linked to original sources
PubMed1989

Laboratory diagnosis of primary hyperparathyroidism.

Although considerable effort has gone into the development and modernization of indirect parathyroid function tests, recent experience indicates that they do not possess adequate diagnostic specificity or sensitivity to provide a definitive diagnosis of HPT when they are most needed, that is, in mild or intermittent hypercalcemia. Conversely, in most research and some commercial laboratories, the combination of hypercalcemia and an elevated mid-molecule or intact PTH level will be diagnostic in more than 90% of patients.

Cyclic AMP↗
PubMed1989

Estrogens and progestins in the management of primary hyperparathyroidism.

Although surgery remains the only curative treatment for primary hyperparathyroidism, interest continues in developing alternative therapy for patients who reject or cannot undergo an operation. For the majority of patients (who are menopausal women), estrogen or progestin therapy may control hypercalcemia and calciuria and reduce the rate of bone turnover. Whether the long-term clinical outcome of hyperparathyroidism is improved by hormone replacement remains to be established.

Estrogens↗
PubMed1989

Transmission of human immunodeficiency virus (HIV) in health-care settings worldwide.

Based on the information available, transmission of human immunodeficiency virus (HIV) can and does occur in health-care settings. No cases of such transmission have been reported from an infected health-care worker to a patient. Transmission of HIV from an infected patient to a health-care worker has been documented after parenteral or mucous-membrane exposure to blood. However, this risk is less than 1%, is limited to exposure to blood, and can be further minimized through adherence to routine infection control measures. Patient-to-patient transmission through invasive equipment or through HIV-infected blood, blood products, organs, tissues, or semen also occurs but can be prevented by proper sterilization of instruments and through donor-deferral, donor screening, and heat treatment of Factors VIII or IX to inactivate the HIV. In health-care settings, prevention of HIV transmission requires education of all health-care workers and ancillary staff, provision of necessary equipment, and strict adherence to general infection control practices.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Rapid diagnosis of leukaemia: a three-stage immunophenotyping technique.

We have developed a three-stage avidin-biotin alkaline phosphatase system (ABAP) for immunophenotyping acute and chronic leukaemias. Air-dried blood and bone marrow films or cytospins were fixed in acetone, methanol-acetone, or methanol-acetone-formalin. A primary monoclonal antibody layer was employed with a corresponding biotinylated anti-species second layer. The third stage was avidin-conjugated alkaline phosphatase and visualisation was achieved with Fast Red TR as diazo salt. This was compared using a limited range of primary antibodies with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method, routinely performed as a five-stage technique. The ABAP technique provided a 2.5 h, reliable, three-stage immunophenotyping procedure without the need for amplification steps. A wider range of first layer monoclonals of any species could be utilised by using the appropriate secondary antibody. Preservation of cell morphology was very good. Smaller amounts of expensive monoclonal antibodies could be used compared to the quantity required with other slide techniques. This approach to immunophenotyping can consequently be employed by any general haematology laboratory to provide a sensitive and inexpensive service. The technique has been in routine diagnostic use for the last 2 years, and consistently good results have so far been achieved in a national external immunophenotyping quality assurance scheme.

Acute Disease↗
PubMed1988

Remission induction in non-Hodgkin lymphoma with reshaped human monoclonal antibody CAMPATH-1H.

A genetically reshaped human IgG1 monoclonal antibody (CAMPATH-1H) was used to treat two patients with non-Hodgkin lymphoma. Doses of 1-20 mg daily were given intravenously for up to 43 days. In both patients lymphoma cells were cleared from the blood and bone marrow and splenomegaly resolved. One patient had lymphadenopathy which also resolved. These effects were achieved without myelosuppression, and normal haemopoeisis was restored during the course of treatment, partially in one patient and completely in the other. No antiglobulin response was detected in either patient. CAMPATH-1H is a potent lympholytic antibody which might have an important use in the treatment of lymphoproliferative disorders and additionally as an immunosuppressive agent.

Aged↗
PubMed1988

Surveillance of health care workers exposed to blood from patients infected with the human immunodeficiency virus.

Since 1983, we have conducted national surveillance of health care workers exposed to blood or body fluids from persons infected with the human immunodeficiency virus (HIV), to assess the risk of HIV transmission by such exposures. As of July 31, 1988, 1201 health care workers with blood exposures had been examined, including 751 nurses (63 percent), 164 physicians and medical students (14 percent), 134 laboratory workers (11 percent), and 90 phlebotomists (7 percent). The exposures resulted from needle-stick injuries (80 percent), cuts with sharp objects (8 percent), open-wound contamination (7 percent), and mucous-membrane exposure (5 percent). We concluded that 37 percent of the exposures might have been prevented. Of 963 health care workers whose serum has been tested for HIV antibody at least 180 days after exposure, 4 were positive, yielding a seroprevalence rate of 0.42 percent (upper limit of 95 percent confidence interval, 0.95 percent). Three subjects experienced an acute retroviral syndrome associated with documented seroconversion; serum collected within 30 days of exposure was not available from the fourth person. Two exposures that resulted in seroconversion were caused by coworkers during resuscitation procedures. We conclude that the risk of HIV infection after exposure to the blood of a patient infected with HIV is low, but at least six months of follow-up is recommended. Many exposures can be prevented by careful adherence to existing infection-control precautions, even during emergencies.

Accidents, Occupational↗
PubMed1988

Transbrachial arteriography: techniques and complications.

A study of 72 patients angiographically examined by the percutaneous transbrachial technique with 4-5F catheters is reported. Even though the patients were preselected to reduce the risk of the technique, an unacceptably high incidence (7%) of major complications, including 3 patients requiring surgery for brachial thrombosis, was encountered. Although transbrachial catheterization with single 4F catheter midstream injections as reported in the literature may be safe, this technique is unwarranted when selective studies are planned and the alternative transfemoral approach is available.

Ambulatory Care↗
PubMed1988

Hyperfractionation of whole-abdomen radiation therapy: salvage treatment of persistent ovarian carcinoma following chemotherapy.

Whole-abdomen radiation therapy has been utilized as primary adjunctive therapy in the management of epithelial ovarian carcinomas with encouraging results. The results reported when using standard fractionation protocols in patients with recurrent or persistent ovarian carcinoma have been poor and treatment-related toxicities have been severe. There are reported theoretical and clinical advantages of hyperfractionation of ionizing radiation in treating malignancies. Fifteen patients have been treated with a twice-a-day whole-abdomen, open-field radiation technique delivering 80 cGy per fraction, to a total dose of 3040 cGy in 19 treatment days. All patients had Stage III epithelial ovarian carcinoma with persistent disease detected at pretreatment laparotomy after cis-platinum-based chemotherapy. All patients had moderately to poorly differentiated tumors with residual disease less than 1 cm. Acute side effects of treatment included mild to moderate nausea and diarrhea. Thrombocytopenia (less than 50,000) was noted in five patients. No bleeding or infectious complications were noted, and no patient required hospital admission for side effects. Disease recurred in nine patients with two still alive 13 and 52 months after starting irradiation. Six patients are currently alive without evidence of disease at follow-up, ranging from eight to 48 months. The mean survival to date is 20 months with four patients alive more than 2 years, and two patients alive for greater than 3 years from their radiation therapy. Patient tolerance has been acceptable, and both the short and long-term toxicities are minimal. Late side effects of treatment have not been noted. This technique offers a chance for a long, disease-free interval and possible cure in well-defined cases of chemotherapy-treated patients with persistent ovarian carcinoma.

Abdomen↗
PubMed1988

Noninvasive determination of ulnar stiffness from mechanical response--in vivo comparison of stiffness and bone mineral content in humans.

An approach referred to as Mechanical Response Tissue Analysis (MRTA) has been developed for the noninvasive determination of mechanical properties of the constituents of the intact limb. Of specific interest in the present study is the bending stiffness of the ulna. The point mechanical impedance properties in the low frequency regime, between 60 and 1,600 Hz are used. The procedure requires a proper design of the probe for good contact of the skin at midshaft and proper support of the proximal and distal ends of the forearm to obtain an approximation to "simple support" of the ulna. A seven-parameter model for the mechanical response is then valid, which includes the first mode of anterior-posterior beam bending of the ulna, the damping and spring effect of the soft tissue between probe and bone, and the damping of musculature. A dynamic analyzer (HP3562A) provides in seconds the impedance curve and the pole-zero curve fit. The physical parameters are obtained from a closed-form solution in terms of the curve-fit parameters. The procedure is automated and is robust and analytically reliable at about the five percent level. Some 80 human subjects have been evaluated by this mechanical response system and by the Norland single photon absorptiometer, providing for the first time in vivo, a comparison of elastic bending stiffness (ulna) and bone mineral content (radius). Three functional parameters of potential clinical value are the cross-sectional bending stiffness EI, the axial load capability Pcr (Euler buckling load) and the bone "sufficiency" S, defined as the ratio of Pcr to body weight. The correlation between EI and bone mineral (r = 0.81) is only slightly less than previous in vitro results with both measurements on the same bone (r = 0.89). When sufficiency is taken into consideration, the correlation of Pcr and bone mineral content is improved (r = 0.89). An implication is that "quality" of bone is a factor which is not indicated by bone mineral content but which is indicated by stiffness. Bone mineral is necessary for proper stiffness but not sufficient. Therefore mechanical measurement should provide a new dimension to be used toward a better understanding of the factors related to bone health and disease.

Biomechanical Phenomena↗
PubMed1988

Intravenous immunoglobulin may lessen all forms of infection in patients receiving allogeneic bone marrow transplantation for acute lymphoblastic leukemia: a pediatric oncology group study.

Fifty patients with refractory acute lymphoblastic leukemia underwent allogeneic bone marrow transplantation after conditioning with high-dose cytosine arabinoside and fractionated total body irradiation. Twenty-nine received intravenous immunoglobulin (i.v.Ig) infusion, primarily to prevent cytomegalovirus infection, and 21 did not. The two groups were biologically comparable. Seven (24.5%) of the i.v.Ig-treated and 14 (66.7%) of the non-i.v.Ig-treated patients developed systemic viral, fungal or bacterial infections and/or interstitial pneumonitis (p less than 0.005), which were fatal in three and 12 cases respectively (p less than 0.001). Currently, 23 (79.3%) of the 29 i.v.Ig-treated and eight (38.1%) of the 21 non-i.v.Ig-treated patients are alive and well (p less than 0.01). We conclude that prophylactic i.v.Ig infusions may reduce the frequency of all forms of serious infection in patients with acute lymphoblastic leukemia undergoing allogeneic marrow transplantation, and thereby improve their survival expectation.

Bone Marrow Transplantation↗
PubMed1987

Age-related rise in parathyroid hormone in man: the use of intact and midmolecule antisera to distinguish hormone secretion from retention.

Circulating levels of parathyroid hormone (PTH) rise with age in normal men and women. To resolve the basis for this observation we measured iPTH in 137 normal men and women, age 23 to 85 years, using two antisera which responded to different portions of the PTH molecule. A midmolecule assay (Mid-PTH) employed antiserum NG-5, which recognizes mid- and carboxy-terminal portions of hPTH, whereas antiserum CK-67, which recognizes determinants in the 1-34 hPTH sequence, was used to measure intact PTH (NH2-PTH). Two-hour fasting urine was collected for measurement of creatinine clearance and excretion indices of phosphorus and cyclic AMP. Serum was analyzed for 25-hydroxyvitamin D (25-OHD) in addition to iPTH. Mid-PTH rose significantly with age in the 72 women (r = 0.38, p less than 0.001) and in the 65 men (r = 0.40, p less than 0.001). NH2-PTH rose with age in women (r = 0.23, p less than 0.05), but a change in men was not significant (r = 0.19, n.s.). Cyclic AMP excretion rose significantly with age in both women (r = 0.42) and men (r = 0.41), whereas phosphorus excretion rose significantly in women only (r = 0.32, p less than 0.01). 25-OHD levels were 27.5 +/- 1.3 ng/ml for women and 26.1 +/- 1.2 ng/ml for men. No change in 25-OHD was observed with age in women, and a significant decrease in men was due entirely to extremely high values in three young subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗