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Biomedical subjects

D J Quint

Publications and source records attributed to D J Quint.

At least 73 records · Page 4Linked to original sources
PubMed1990

Amyloidosis of the spine in a patient on long-term hemodialysis.

A 54-year-old man with a history of renal failure treated with hemodialysis for over 10 years presented with clinical signs and symptoms and plain radiographic, computed tomographic and magnetic resonance imaging features of cervical vertebral osteomyelitis with spinal cord compression. Decompressive surgery revealed amyloid deposition. In the setting of chronic hemodialysis, differentiation between amyloid deposition and osteomyelitis may not be possible on an imaging basis necessitating biopsy for diagnosis.

Amyloidosis↗
PubMed1990

In vitro and in vivo studies with purified recombinant human interleukin 5.

The functional activities of highly purified recombinant human IL 5 (hIL 5) have been characterized on a number of cell types in vitro and in BALB/c mice in vivo. In vitro, hIL 5 could induce the differentiation of eosinophils from precursors in both human and mouse bone marrow with approximately the same efficiency. A mouse IL 5/3-dependent B cell line, LyH7.B13, was found to proliferate in response to hIL 5 but not human interleukin 1 (IL 1), interleukin 2 (IL 2), interleukin 3 (IL 3), interleukin 4 (IL 4), interleukin 6 (IL 6), interferon-gamma (IFN-gamma), or granulocyte macrophage-colony stimulating factor (GM-CSF) and was at least 10-fold more sensitive than BCL1 mouse lymphoma cells. We have successfully used this cell line to demonstrate the production of IL 5 by human T cell clones. In marked contrast to its effects on murine B cell lines, hIL 5 had no demonstrable activity on CD23 expression, anti-mu costimulated proliferation or IgM, IgG, or IgE production by tonsillar B cells and did not influence such responses triggered by IL 4. BALB/c mice injected with hIL 5 for 7 consecutive days were shown to develop an eosinophilia comparable to that induced by infection with the parasite Mesocestoid corti.

Animals↗
PubMed1990

Magnetic resonance demonstration of vertebral artery dissection. Report of two cases.

Vertebral artery dissection may be spontaneous or related to some traumatic event. Diagnosis has usually been made by angiography, an invasive procedure with certain well-known risks. The authors describe the magnetic resonance (MR) appearance (both on conventional spin-echo and on gradient refocused "flow" sequences) in two patients with vertebral artery dissection confirmed by angiography. It is proposed that the less invasive MR imaging might be the imaging modality of choice for initial evaluation of suspected vertebral artery dissection.

Adult↗
PubMed1990

Immunoregulation in the common marmoset, Calithrix jaccus: functional properties of T and B lymphocytes and their response to human interleukins 2 and 4.

Non-human primates have been used to study immune function to a much lesser extent than readily available strains of inbred rodents. Nevertheless, in situations where it might be desirable, but impossible, to study human immune responses in vivo, lower primates could provide an acceptable alternative. In order to extent the knowledge of T- and B-lymphocyte function in lower primates, the common marmoset Callithrix jaccus was used as an experimental model. The functional similarities between this species and humans at the level of T-B co-operation in the antibody response were examined, and xenoreactive T-lymphocyte clones were obtained from marmoset spleen cells using Epstein-Barr virus (EBV)-transformed human B cells as stimulators. These clones could act as helper cells when co-cultured with human B lymphocytes, inducing the secretion of both IgM and IgG. Lymphokine production by mitogen-stimulated marmoset T-cell clones was also examined. Interleukins (IL) 2 and 4 activities were detected in clone supernatants using bioassays and interferon-gamma (IFN-gamma) was detected using a solid-phase ELISA system. However, SDS-PAGE analysis of biosynthetically labelled marmoset and human T-cell clone supernatant proteins revealed major differences between the soluble T-cell products of the two species. The proliferative responses of marmoset T and B cells to recombinant human IL-2 and IL-4 were also examined. Stimulation of [3H]thymidine uptake was detected in both T cell- and anti-IgM-stimulated B-cell cultures with both of the lymphokines. These results suggests that the key components of the antibody response are functionally conserved between lower primates and man and that the common marmoset may be useful as an in vivo model of immune function, particularly with regard to the role of interleukins such as IL-2 and IL-4.

Animals↗
PubMed1989

Functional and phenotypic properties of T-cell clones which regulate IgE synthesis.

We have generated a panel of T-lymphocyte clones from a patient suffering from the hyper IgE syndrome, and have attempted to correlate the ability of each to help IgE responses in vitro with the profile of lymphokines secreted after mitogenic stimulation. Clones which showed positive IgE helper activity released larger amounts of interleukin-4 (IL-4) than the non-helpers, which tended to release more interleukin-2 (IL-2). Surprisingly, all clones released moderate amounts of gamma interferon (IFN), which has been shown to inhibit the action of IL-4 on B cells. The clones were analysed by indirect immunofluorescence using monoclonal antibodies to CDw29 and CD45R (4B4 and 2H4 respectively). Those T cells which could provide strong helper activity for all isotypes, expressed high levels of CDw29 and low CD45R. These data suggest that these CD4-positive T cells expressing surface antigen of the 'memory' subset i.e. CDw29, are involved in IgE isotype regulation by virtue of their ability to secrete IL-4 upon antigenic stimulation.

Antigens, Differentiation↗
PubMed1989

Intraluminal clot in the vertebrobasilar circulation: clinical and radiologic features.

We studied 15 patients with angiographically documented intraluminal clot in the vertebrobasilar (VB) circulation and ischemic stroke. Progressive brainstem signs were the most common presentation; the neurologic deficit was maximum at stroke onset in 4. Seven experienced their first symptoms during sedentary activities. Thirteen of the initial 15 CTs revealed infarcts in the VB territory, 7 with multiple foci. Intraluminal clot was present in the vertebral artery in 7 patients (2 bilateral), basilar artery in 7, posterior cerebral artery in 5, and superior cerebellar artery in 1. Multiple clots were seen in 5 patients. Stroke risk factors were present in the majority of cases. Although cardiac source embolism was the most common single etiology (4 patients), most patients had other causes including migraine, coagulopathy associated with malignancy and nephrotic syndrome in systemic lupus erythematosus, vertebral artery dissection with local embolism, delayed irradiation arteriopathy, and a fusiform, ectatic basilar artery. Six (40%) died within 5 months of follow-up. Intraluminal clot in the posterior circulation is a marker for multiple stroke mechanisms, not all of which are embolic. Intraluminal clot should prompt investigations into occult risk factors when no cause appears obvious.

Adult↗
PubMed1989

Functional and phenotypic analysis of human T-cell clones which stimulate IgE production in vitro.

Peripheral blood mononuclear cells (PBMC) from a patient suffering from the hyper IgE syndrome were used to generate phytohaemagglutinin (PHA)-expanded T-cell clones (all CD4+, CD8-, CD23-). A selection of the clones was tested for their ability to help IgE secretion by culturing with normal B cells in the presence of solid-phase antibody to CD3. Supernatants were harvested on Day 7 and assayed by ELISA for IgE, IgG and IgM. Lymphokine secretion by the clones was assessed by culturing clones for 24 hr with solid-phase antibody to CD3 followed by assay of the supernatants for IL-2, IL-4 and interferon-gamma (IFN-gamma) production. In addition, clones were analysed by flow cytometry for CDw29 and CD45R expression. Initial experiments with seven clones indicated that those clones that could help IgE secretion also stimulated optimal IgG and IgM responses. All clones appeared to secrete IL-2, IL-4 and IFN-gamma, although the amounts of each varied. These results confirm recent findings that human T-cell clones do not fall into Tinf (Th1) and Th (Th2) type subsets as described in the mouse. There was no clear correlation between the lymphokines secreted by the clones and their capacity to help IgE production. However, the helper function of the clones for all isotypes, including IgE, appeared to be related to the level of expression of the surface antigen CDw29.

Antigens, Differentiation↗
PubMed1988

Epidural lipomatosis.

The authors report six new cases of epidural lipomatosis--a rarely described entity characterized by increased extradural fat within the spinal canal causing compression of the spinal cord and neurologic deficits. Five of the six patients had a history of chronic steroid use. Myelography of the thoracic spine, followed by computed tomography (CT), was performed in five patients, and magnetic resonance (MR) imaging was done in three. Myelographic findings were abnormal in three patients and normal in two, compared with those of postmyelography CT, which revealed increased accumulation of extradural fat in all five patients. In the three patients in whom it was performed, MR imaging also showed the increased spinal canal fat. Four patients underwent surgery, which revealed an increased amount of histologically normal, unencapsulated fat in all cases. The diagnosis of epidural lipomatosis should be based on a combination of clinical, imaging, surgical, and histologic findings. If the clinical suspicion is high, even if results of myelography are normal, further evaluation with post-myelography CT or MR imaging should be considered.

Adult↗
PubMedDate not supplied

Importance of absence of CSF pulsation artifacts in the MR detection of significant myelographic block at 1.5 T.

MR imaging was performed on 21 patients who had high-grade myelographic block due to various diseases in all spinal compartments (extradural, intradural/extramedullary, and intramedullary) and in all portions of the spinal canal (cervical, thoracic, and lumbosacral). Loss of CSF pulsation artifacts due to significant compression of the spinal cord was demonstrated on non-motion-compensated T2-weighted examinations in each case. We believe that the absence of such artifacts on these sequences indicates significant spinal cord compression in patients without classic signs and symptoms of cord compression but with intraspinal disease identified on T1-weighted studies.

Adolescent↗
PubMedDate not supplied

MR of myelomatous meningitis.

In a 56-year-old woman with multiple myeloma involving the leptomeninges diffusely, MR of the spine showed multiple vertebral compression fractures and marked enhancement of the cauda equina region. Intracranial MR showed pathologic enhancement of the left third and fifth cranial nerves.

Cauda Equina↗
PubMedDate not supplied

Posttraumatic rhinolith.

Rhinolith, calcified concretion of a nidus within the nasal cavity, is a possible diagnosis for certain patients with densely mineralized lesions that appear benign and without bone destruction.

Aged↗
PubMedDate not supplied

Multiple sclerosis presenting as Parinaud syndrome.

The authors report a patient presenting with a 1-week history of paresis of upward gaze as his initial manifestation of demyelinating disease. They stress that: 1) multiple sclerosis can present as Parinaud syndrome (paralysis of upward gaze); and 2) it is important to rule out a non-contour-deforming intraaxial midbrain lesion if a posterior third ventricle or pineal region mass is not identified on screening studies in these patients.

Humans↗