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Biomedical subjects

D Green

Publications and source records attributed to D Green.

At least 217 records · Page 12Linked to original sources

The effects of local anesthetics containing epinephrine on digital blood perfusion. 1978.

Digital perfusion research was conducted with two local anesthetics, lidocaine and bupivacaine. The studies were performed utilizing both anesthetic agents, plain and with various concentrations of epinephrine. The drugs' effects on blood perfusion over a 24-hr. period were recorded and discussed. The onset and duration of anesthesia were also compared.

Anesthesia, Local↗

Sclerotherapy for varicose and telangiectatic veins.

Varicose veins of the lower extremities are present in approximately 20 percent of adults. They are often symptomatic and may contribute to the development of cutaneous changes of venous insufficiency. Sclerotherapy is a nonsurgical procedure to eradicate varicosities. It can be performed in the office and is more cost-effective than traditional surgical vein stripping, which requires hospitalization and a recuperation period. Sclerotherapy is relatively safe and effective and may be used to treat both varicose veins and telangiectatic "spider" veins of the lower extremities.

Contraindications↗

Pressure sore anemia: response to erythropoietin.

Anemia in patients with grade IV pressure sores is usually refractory to therapy with iron salts, and red cell transfusions are commonly required when reconstructive surgery is performed. The anemia is characterized by hypoferremia, reticulocytopenia, and normal-to-increased serum ferritin. Five patients with this anemia were treated with recombinant human erythropoietin (rHuEPO) in doses of 50 to 100 U/kg, given subcutaneously three times per week. The hemoglobin increased in every patient; the mean (+/- SD) value at the initiation of treatment was 8.8 +/- 1.0 g/dL, and after a median of 4 weeks of therapy, it was 12.4 +/- 1.6 g/dL (p less than .001). No adverse effects of treatment were observed. It is concluded that rHuEPO is a promising new agent for pressure sore anemia, but randomized, controlled clinical trials will be required to firmly establish its place in the management of patients with this type of anemia.

Adult↗

Deep vein thrombosis and pulmonary embolism: prevention, diagnosis, and treatment.

Pulmonary embolism (PE) is a significant cause of mortality in the elderly. More than 90% of pulmonary emboli originate from a thrombus in the deep veins of the legs. Proper diagnosis and treatment of deep vein thrombosis (DVT) are thus essential to prevent PE. Diagnosis of new or recurrent DVT is based on the results of one or more tests, including impedance plethysmography (IPG) or duplex venous scan; venography can often be avoided, based on results of initial testing. For suspected PE, perfusion lung scanning is the initial test of choice, followed by IPG/duplex or venography. Pulmonary angiography is indicated for patients with decreased cardiorespiratory reserve. Decisions governing prophylaxis of DVT are based on individual relative risk; prophylactic therapies include intermittent compression, low-dose heparin, and oral anticoagulants. Management of thromboembolism requires IV and oral anticoagulant therapy.

Angiography↗

Antigen-specific therapy of experimental allergic encephalomyelitis by soluble class II major histocompatibility complex-peptide complexes.

Experimental allergic encephalomyelitis is a T-cell-mediated, major histocompatibility complex (MHC) class II gene-linked autoimmune demyelinating disease of the central nervous system. To develop therapies that will specifically inactivate only the autoantigen-reactive T cells, mice were treated with soluble MHC class II molecules that had been complexed with encephalitogenic peptides. Intravenous injections of 300 micrograms of complexes consisting of encephalitogenic peptide 91-103 of myelin basic protein plus I-As protein on day 0, 4, and 7 were effective in preventing experimental allergic encephalomyelitis. Similarly, administration of 45 micrograms of I-As protein complexed to peptide 139-151 from proteolipoprotein on day 1, 4, and 7 prevented mortality and significantly reduced paralysis induced by immunization with the encephalitogenic proteolipoprotein peptide. Histological examination of sections of animal brains revealed that treatment with I-As protein plus myelin basic protein 91-103 peptide prevents the development of inflammatory lesions characteristic of experimental allergic encephalomyelitis. Thus, treatment with MHC-self-peptide complexes could serve as a highly specific therapeutic modality in treating autoimmune disease when the putative autoantigen and the MHC restricting elements are known.

Animals↗

Cytotoxic suppression of acquired factor VIII:C inhibitors.

Autoantibodies directed against factor VIII:C (FVIII:C) are associated with serious and often fatal bleeding. Efforts to suppress or abolish these antibodies with cytotoxic agents are frequently successful if antibody titer is not too high or there is an associated disease that undergoes remission. Corticosteroids alone may hasten antibody disappearance in almost half of patients, and cyclophosphamide is useful in those who are resistant to steroids administered alone or in combination. Patients refractory to these regimens may respond to a more aggressive approach using combination chemotherapy with cyclophosphamide, prednisone, and vincristine. Unfortunately, because of the rarity of this disorder, randomized, controlled trials have not been conducted either to compare treatments directly or to examine the factors presaging favorable outcomes. Recently, however, a multicenter trial comparing prednisone, cyclophosphamide, and the combination has been initiated, and some preliminary data from this investigation are presented. Approaches to the recognition and clinical management of this disorder also are described.

Autoantibodies↗

CD4 cells in HIV-1 infected hemophiliacs: effect of factor VIII concentrates.

The goal of this study was to determine the long-term clinical outcome of Human Immunodeficiency Virus (HIV) infection in a group of HIV-seropositive hemophiliacs for whom the dates of seroconversion were known and to investigate whether the use of monoclonal antibody purified factor (high purity) concentrate and treatment with zidovudine may alter the effect of HIV infection in seropositive hemophiliacs. Twenty-eight hemophiliacs were followed for up to 9 years after seroconversion. In addition, 13 seropositive patients who elected to receive (high purity) factor VIII concentrate for up to 1.5 years were compared to a contemporaneous concurrent control group of 8 seropositive patients treated with intermediate purity factor VIII concentrate, and then both groups were followed for an additional 1.5 years while receiving zidovudine. The acquired immunodeficiency syndrome (AIDS) developed in 9 of 28 patients (33%) from 1 to 9 years following seroconversion. CD4 cell count declined at a rate of 13.5% per year for the cohort but for persons 25 years and above the rate was significantly higher (17.5 +/- 9.2% per year vs. 9.5 +/- 4.7%, mean +/- SD, p less than 0.05) than in those under 25. All three patients who had undergone splenectomy developed AIDS. Subjects treated with high purity concentrates, with the exception of one patient who developed the nephrotic syndrome secondary to amyloidosis, had stable CD4 cell counts. On the other hand, all patients receiving intermediate purity concentrates had a decline in CD4 cells, and the difference from initial levels was highly significant (p = 0.01). The CD4 cell concentrations in these patients were stable after treatment with zidovudine.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

HLA-D region antigens in patients with rheumatoid arthritis.

We studied the distribution of HLA-D region antigens in 2 groups of rheumatoid arthritis (RA) patients: those with mild, nonprogressive disease, and those with severe disease. The results demonstrate that DR4 was significantly increased in both RA patient populations. The frequencies of DR1 and DR4-associated DQw7 alleles, however, were different in these 2 groups of patients. DR1 was significantly increased only in patients with mild RA, and DR4-associated DQw7 was significantly increased only in patients with severe disease. The results of the present study, together with previous data from our laboratory and from other investigators on the incidence of HLA-D region antigens in RA, suggest that both DR and DQ (A and B) genes may be important in conferring susceptibility to RA; DR in the mild forms of the disease, and DQ in severe RA.

Alleles↗

Prevention of thromboembolism after spinal cord injury.

Thromboembolism is a major cause of morbidity and mortality in patients with spinal cord injury. The prevalence of DVT approaches 100%, and 1 to 2% will die of PE. Following injury, there is hypercoagulability as reflected by an increase in von Willebrand factor activity and antigen, and increased platelet reactivity to collagen. Thrombosis usually occurs 1 to 3 weeks after injury, with a peak between days 7 and 9. Intermittent calf compression boots reduce the frequency of thrombosis to 40%, and the addition of aspirin, 300 mg twice daily, and dipyridamole, 75 mg thrice daily, decrease this further to 25%. In an attempt to provide more effective prophylaxis, a further trial was conducted using heparin. Twenty-nine patients were randomized to receive 5000 U subcutaneously every 12 hours and compared with an equal number of patients treated with doses of heparin adjusted to prolong the APTT to 1.5 times control values; the mean dose was 13,200 U every 12 hours. Thromboembolism occurred in 9 (31%) of those on the fixed dose (6 DVT and 3 PE) and only 2 (7%) on the adjusted dose (p less than 0.05); however, 7 (24%) of the patients receiving the higher doses of heparin had bleeding compared with none of those on the fixed dose (p less than 0.02). Most recently, we have compared the safety and effectiveness of a low molecular weight heparin (Logiparin, Novo) with standard heparin. The former was given once daily in a dose of 3500 anti-Xa units, and the latter was 5000 U every 8 hours, both given subcutaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Anticoagulants↗

Coronary thrombosis in a patient with May-Hegglin anomaly.

May-Hegglin anomaly (MHA) is a rare hereditary condition that is characterized by cytoplasmic inclusions in leukocytes and giant platelets. Many patients have some degree of thrombocytopenia. Most individuals with MHA are asymptomatic, but 25-43% of patients previously reported have had a hemorrhagic tendency. The authors describe a patient with MHA who had no history of hemorrhage but who developed complete coronary thrombosis after attempted angioplasty despite an apparent platelet count of 24,000 per mm3. Laboratory investigations revealed a normal bleeding time, normal platelet aggregation, and an increase in the size of approximately two-thirds of the platelets. The calculated platelet mass was near normal, which probably explains the thrombosis despite a decrease in platelet numbers. The authors conclude that in some patients with MHA platelets are functionally active both in vivo and in vitro.

Blood Platelets↗

A comparative study of ethamsylate and mefenamic acid in dysfunctional uterine bleeding.

The effects of ethamsylate and mefenamic acid on menstrual blood loss were compared in a double-blind trial in 34 women with menorrhagia. Both drugs produced statistically significant reductions in blood loss during the 3 months of treatment; the overall reduction was 20% in the ethamsylate group and 24% in the mefenamic acid group. Compared with pretreatment values, blood loss was significantly less in each of the 3 treatment months in the mefenamic acid group, but only in the second and third months of treatment in the ethamsylate group. However, more women had a clinically useful reduction in blood loss (greater than 40%) in the ethamsylate group. The onset of effect of mefenamic acid was rapid but ethamsylate showed a comparatively greater effect as the trial progressed. Cessation of treatment was followed by an increase in blood loss, more pronounced in mefenamic acid group who reverted to pre-treatment levels. A greater number of side-effects were reported with mefenamic acid.

Adolescent↗

Nuclear mutation restores the reduced CO2/O2 specificity of ribulosebisphosphate carboxylase/oxygenase in a temperature-conditional chloroplast mutant of Chlamydomonas reinhardtii.

The Chlamydomonas reinhardtii temperature-sensitive mutant 68-4PP results from a mutation within the chloroplast gene that encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase. When grown at the permissive temperature (25 degrees C), the mutant has a reduced level of holoenzyme protein, and the purified enzyme has a lower CO2/O2 specificity than the wild-type enzyme. At the nonpermissive temperature (35 degrees C), the holoenzyme level is greatly reduced, and the mutant is unable to grow photosynthetically. When photosynthesis-competent revertants of 68-4PP were selected at 35 degrees C, a nuclear mutation was identified that suppresses the temperature-sensitive phenotype by enhancing both the activity and amount of the mutant enzyme. More significantly, the reduced CO2/O2 specificity of the 68-4PP enzyme is restored to the wild-type value. However, the nuclear suppressor mutation alone does not produce a phenotype different from wild type, and the CO2/O2 specificity of the suppressor strain's enzyme is normal. We have cloned and completely sequenced the two small-subunit genes from the suppressor strain, but no mutation has been found. These results suggest that some other nuclear-encoded protein is able to influence the structure of the holoenzyme, which in turn influences the CO2/O2 specificity factor.

Base Sequence↗