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Biomedical subjects

A Ammar

Publications and source records attributed to A Ammar.

At least 91 records · Page 5Linked to original sources
PubMed1991

Excessive sweating: an uncommon sign of basilar artery occlusion.

Excessive sweating of the face and, to a lesser degree, of the thorax and limbs, occurred after basilar artery occlusion in a 15 year old Saudi boy. Magnetic resonance imaging (MRI) showed a limited bilateral paramedian infarction of the rostral ventral pons. Basilar artery occlusion in children and adolescents is a rarity. Excessive sweating following such a stroke is rare in any age group. Clinico-anatomical correlations are discussed.

Adolescent↗
PubMed1991

Biological and biochemical characterization of a factor produced spontaneously by adherent cells of human immunodeficiency virus-infected patients inhibiting interleukin-2 receptor alpha chain (Tac) expression on normal T cells.

Adherent cells from human immunodeficiency virus (HIV)-infected subjects but not from normal blood donors, patients with Gram-positive or -negative bacteremia, active tuberculosis, toxoplasmosis, pulmonary aspergillosis, and cytomegalovirus infection produce spontaneously an activity which inhibits alpha chain of interleukin-2 (Tac) expression and interleukin 2 (IL-2) production by normal activated T cells and IL-2 production by these cells. A similar biologic activity was detected in culture supernatants of in vitro HIV-I-infected normal adherent and leukemic U937 cells. Tac-inhibitory activity is not cytotoxic and it could be detected in serum-free conditioned media. Recombinant granulocyte/macrophage colony-stimulating factor and phorbol myristate acetate stimulation of patients' and normal adherent cells did not enhance specifically the production of the Tac inhibitor. Biologically active conditioned media did not contain infectious virus as well as secreted p24, gp120 viral proteins; the biologic activity could not be abolished by anti-p24, anti-gp120, and anti-nef monoclonal antibodies or human purified polyclonal anti-HIV IgG. Gel filtration of conditioned media followed by anion exchange chromatography resulted in a 1,200-fold degree of purification and revealed that the biologically active molecule was cationic. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of this fraction and gel elution of the proteins showed that the biologic activity was associated with a 29-kD protein which was distinct from alpha- or gamma-interferon, tumor necrosis factor-alpha, and prostaglandin E2. The above findings demonstrate the production of inhibitory factor(s) during HIV infection, which might be involved in the pathogenesis of the patients' immune defect.

Cell Adhesion↗
PubMed1991

[Hoffmann-Zurhelle superficial cutaneous lipomatous nevus. Apropos of a case].

The authors report a case of lipomatous naevus present for 35 years, and therefore probably congenital, in a 48 year old female patient. This bulging lesion was 2.5 cm in diameter with a slightly encephaloid appearance. The authors reviewed the limited literature on the subject in order to more clearly define this hamartomatous lesion which has a constant histological appearance, but very variable clinical and macroscopic features.

Diagnosis, Differential↗
PubMed1991

Production of a tac inhibitory activity by adherent cells of HIV-infected subjects at different clinical stages.

Studying the mechanisms of the impaired T-cell colony growth from HIV-infected subjects, we have demonstrated that depletion of adherent cells from some patients' peripheral blood mononuclear cells enhanced the plating efficiency of T colony-forming cells. We report here that media conditioned by patients' cells but not normal adherent cells could inhibit the expression of the interleukin-2 receptor alpha (IL-2R alpha) chain but not the IL-2R beta chain in a dose-dependent manner. This inhibitory activity was produced by macrophage-monocyte cells since they displayed the My9+ My7+ OKM1+ phenotype and since adherent cell depletion by complement-mediated cytotoxicity with the My9 monoclonal antibody completely abrogated production of the inhibitory activity. A similar inhibitory activity, which could not be recognized by anti-p24 or anti-gp 120 monoclonal antibody or purified human anti-HIV immun]gobulin G in Western blot assays, could also be detected in culture supernatants of in vitro HIV-infected normal adherent and U937 leukemic cells. Production of IL-2R alpha chain inhibitory activity was associated with a decreased mitogen-induced expression of IL-2R alpha chain on patients' PBMC in 8 of 10 studied cases. Its production could be detected in 82, 58, and 91% of media conditioned by adherent cells from stage II, III, and IV patients, respectively. The amount of IL-2R alpha chain inhibitor released by patients' adherent cells increased during the deterioration of the patients' clinical status, and zidovudine treatment completely abrogated its production in all patients. These findings strongly suggest that production of IL-2R alpha chain inhibitory activity is involved in the pathophysiology of the impaired T-cell responses during HIV infection and could be of clinical relevance during the patients' follow-up.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Neural tissue compatibility of Teflon as an implant material for microvascular decompression.

Teflon is utilized in neurosurgery as well as in plastic, vascular and heart surgery. Although the effect of Teflon on different types of cells and tissues has been previously studied, we are not aware of any study in which the effect of Teflon was tested on cells of the central nervous system. We have therefore examined the tissue compatibility of spongy and fibrous Teflon by directly exposing the Teflon to dissociated cerebellar cells containing both glia and neurons in tissue culture. Daily examination of the growth of the cells adjacent to Teflon fibers using an inverted phase contrast microscope revealed that Teflon has little or no effect on the growth of these cells. When the cells are fixed after 7 days in culture and stained by the Jenner-Giemsa method, adhesion of both glia and neurons to the surface of the Teflon was seen. Attachment of neural cells to the Teflon was not extensive, as was shown by indirect immunofluorescence technique in connection with double-label staining with antiGFAP as glia marker and anti-M6 as mouse neuron marker. Thus, these experiments show that Teflon is relatively inert when used as an implant in the central nervous system.

Biocompatible Materials↗
PubMed1990

Brain abscess in Saudi Arabia.

There are significant variations among countries in the incidence of brain abscess. We report here 26 cases of brain abscess treated at the Neurosurgery Department of King Faisal University and Dammam Central Hospital Saudi Arabia over a six year period (1982-1988). This is 2.3% of total admissions to the two neurosurgery departments serving a population of approximately 1.2 million in the same period. Young males were most often affected (M/F ratio 3.3:1; 31% were less than 15 years old, 46% aged between 15-39 years, and 23% older than 40 years). Streptococcus was found to be the most common microorganism (38.4%). Mixed infection was seen in 15.3%, and sterile abscesses were found in 11.5% of the patients after aerobic and anaerobic cultures of the pus. Chronic otitis media and paranasal sinusitis predisposed the patients to abscess formation in 57.6% of the cases. The temporo-parietal area was the commonest site. Epilepsy was a complication in 30.7% of our patients, and the mortality rate was 15.3%.

Brain Abscess↗
PubMed1990

Seroprevalence of HIV-2 infection in Greece (Crete).

The seroprevalence of HIV-2 was evaluated in 20,407 consecutive normal blood donors, 100 homo- and/or bisexuals, and 7,020 heterosexuals presenting for an HIV test using an EIA test. Sixty-seven sera were revealed to be repeatedly positive. Analysis by Western blot confirmed the infection in four cases, an indeterminate (antibodies against only the gag-encoded proteins) pattern was revealed in 25 cases, whereas 38 sera were negative. Three of the four HIV-2-positive sera also reacted with two distinct, but close, synthetic peptides homologous to viral gp36. The fourth serum, which did not display antibodies against gp36 on Western blot, did not react with gp36-derived synthetic peptides. None of these sera reacted with native HIV-1 antigens or synthetic peptides homologous to gp41. Sera with an indeterminate HIV-2 Western blot did not react with gp36-derived synthetic peptides. Although 10 of them also displayed an indeterminate HIV-1 Western blot, no serum sample reacted with two gp41-derived synthetic peptides or proved to be positive when they tested for p24 antigen. One bisexual and one heterosexual HIV-2 positive subject reported sexual contacts with West Africans, whereas two other heterosexuals had had multiple sexual partners from different countries.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Impaired in-vitro proliferation of hemopoietic precursors in HIV-1-infected subjects.

Patients with acquired immunodeficiency syndrome (AIDS) and persistent lymphadenopathy syndrome (LAS) display significant hematological abnormalities of one or more cell lineages. In order to understand the pathophysiologic mechanisms leading to these abnormalities we studied the proliferation capacity of pluripotent and committed hemopoietic precursors using in-vitro colony assays. Anemia, leukopenia and thrombopenia were relatively frequent findings in HIV-infected subjects irrespectively of the patients' clinical status. The colony growth capacity of AIDS patients' GM-CFU and BFU-E was significantly decreased whereas no GEMM-CFU colonies could be obtained. There was no correlation between the number of BFU-E and GM-CFU colony number and the hemoglobin or the absolute number of polynuclear cells, respectively. The plating efficiency of both committed and pluripotent hematopoietic precursors from HIV infected patients could not be enhanced when additional exogenous recombinant GM-CSF, human interleukin 3 or erythropoietin were added in contrast to normal patients' cells. In addition, the impaired colony growth of these precursors could not be restored after adherent or T-cell depletion or the addition of normal allogenic irradiated adherent or/and T cells. Since this colony growth abnormality was also detected in HIV seropositive asymptomatic subjects our findings strongly suggest that the in-vitro growth of hematopoietic precursors is affected early after HIV-1 infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

The outcome of head injury: the Saudi experience.

The outcome in 159 cases of head injury was evaluated in terms of the Glasgow Coma Scale (GCS) score, age, and computed tomographic (CT) findings. Children below the age of 10 accounted for 30% of the head-injured patients, and 69% were Saudis. 81% of the patients had a GCS score of 8 or higher, and in this group the outcomes were favorable. In contrast, 19% had an initial GCS score of 7 or less, tended to be older, and had worse outcomes, with a mortality rate of 68%. The initial GCS score, age, presence or absence of associated injuries, and the degree of midline shift according to CT were useful prognostic indices in patients with head injury.

Adolescent↗
PubMed1989

The outcome of head injuries: the Saudi experience.

One analysis of the outcome of 159 cases of head injuries was based on patients' admission Glasgow Coma Scale (GCS), score, age, CT scan findings and uniform protocol of management. Fifty-three percent of the patients were children below the age of 10 years and 70% of all patients were Saudis. Eighty-point-five percent (80.5%) of the patients had a GCS score of 8 or more and their outcome was favorable. By contract, the 19.5% who had an initial GCS score of 7 or less tended to be older and had a worse prognosis (mortality 68%). A high initial GCS score, old age, associated multiple injuries and a shift of more than 4 mm of the midline structures on CT scan of the brain are useful prognostic indices in predicting the outcome of head injury.

Adolescent↗
PubMed1988

Prognostic value of blood and bone marrow T-colony-forming cells (T-CFC) in patients with lymphadenopathy syndrome (LAS).

The in vitro proliferation capacity of peripheral blood committed T-cell precursors (T-CFC) from LAS patients was studied in order to define whether this parameter could be associated with transition to AIDS. In all patients a significantly (P less than 0.0001) decreased plating efficiency was detected. However, the lowest T-cell colony growth (less than 50 colonies/5 x 10(4) cells) was observed in the 23 patients who subsequently developed the full-blown disease within 150-570 days. Conversely, only one patient (n = 107) whose T-CFC generated greater than 50 colonies/5 x 10(4) cells developed AIDS after a mean follow-up of 867 days (range 120-1260 days). T-CFC from these patients displayed an impaired in vitro differentiation and self-renewal capacity which was independent of the clinical evolution of the disease. In 5 out of 12 AIDS patients, adherent cell-depletion of peripheral blood mononuclear cells (PBMC) enhanced the plating efficiency. Moreover, patients' but not normal adherent cells could inhibit normal T-cell colony growth in a dose-dependent manner. Media conditioned by patients' unstimulated adherent cells (LCM-A+p) also inhibited normal T-cell colony formation. In addition, LCM-A+p were capable of inhibiting interleukin 2-receptor (IL 2-R) expression and interleukin 2 (IL 2) production by normal mitogen-stimulated T-cells. These findings suggest that adherent cell-derived inhibitory activity(ies) could be responsible for the low T-cell colony formation observed in some AIDS patients.

AIDS-Related Complex↗
PubMed1987

Peripheral blood adherent cells from AIDS patients inhibit normal T-colony growth through decreased expression of interleukin 2-receptors and production of interleukin 2.

Adherent cells display an important accessory role on normal T-cell colony formation. Since the in-vitro proliferation of T colony-forming cells (T-CFC) from AIDS patients is extremely impaired we studied the effect of patients' adherent cells on T-CFC growth. Patients' peripheral blood mononuclear cells (PBMC) were fractionated on the basis of rosette formation with sheep red blood cells and complement-mediated cytotoxicity with OKT3 monoclonal antibody (E-T3-). Both mature (E+) T cells and E-OKT3- cell fractions failed to generate T-cell colonies although colony growth could be obtained from unfractionated PBMC. In five out of 12 AIDS patients, adherent cell-depletion of PBMC enhanced the plating efficiency. Moreover, patients' but not normal adherent cells could inhibit normal T-cell colony growth in a dose-dependent manner. Media conditioned by patients' unstimulated adherent cells (LCM-A+p) also inhibit normal T-cell colony formation. In addition, LCM-A+p were capable of inhibiting interleukin 2-receptor (IL2-R) expression and interleukin 2 (IL2) production by normal mitogen-stimulated T cells. These LCM-A+p did not contain detectable reverse transcriptase activity nor could they infect the CEM T-cell line which is permissive to human immunodeficiency virus (HIV). Conversely, this adherent cell-derived inhibitory activity could be abrogated by heating or treatment with proteolytic enzymes. These findings indicate that the low T-cell colony formation in some AIDS patients could be due to adherent cell-derived inhibitory activity(ies).

Acquired Immunodeficiency Syndrome↗
PubMed1986

[Treatment of cerebral aging disorders with Ginkgo biloba extract. A longitudinal multicenter double-blind drug vs. placebo study].

The effectiveness of Ginkgo biloba extract in the treatment of cerebral disorders due to ageing was evaluated in a multicentric, double-blind, drug versus placebo trial involving 166 patients. In this study carried out under strict methodological conditions a specially devised geriatric clinical evaluation scale was used. The results confirmed that Ginkgo biloba extract is effective against cerebral disorders due to ageing. The difference between control and treatment groups became significant at 3 months and increased during the following months. These results were concordant with the overall clinical assessment made by the specialist in charge.

Aged↗
PubMed1986

Potential ganglioside antigens associated with human gliomas.

Gangliosides in human gliomas were investigated and found to have an altered composition and concentration as compared to normal grey and white matter of brain. The major gangliosides GM1, GD1a, and GT1b were markedly reduced in the tumour tissue and in contrast there was an increase of gangliosides GM3 and GD3, which often appeared as the dominating ones. Moreover, the tumours contained gangliosides, both mono- and oligosialylated, which could not be detected in the normal brain. The concentration of gangliosides, 0.7 +/- 0.4 mumol sialic acid/g, was significantly lower as compared to normal brain grey (p less than 0.001) and white matter (p less than 0.01), which contained 3.5 +/- 0.3 and 1.2 +/- 0.3 mumol sialic acid/g respectively. The tumour tissue concentration of phospholipids was 14 +/- 8 and of cholesterol 19 +/- 12 mumol/g. The appearance in glioma tissue of gangliosides that are not found in normal brain tissue suggests that these are tumour associated and might serve as surface antigens detectable by specific monoclonal antibodies.

Adult↗
PubMed1984

Tissue compatibility of different intracranial implant materials: in-vivo and in-vitro studies.

Tissue compatibility of different intracranial implant materials was studied by a tissue culture method using fibroblasts. The same materials were implanted in the crania of rabbits for two months. Undecalcified sections of rabbit crania, including the materials, were stained with Fuchsin and Methylene Blue and Masson-Goldner methods. Soft X-ray was used to detect new bone formation. The materials used were alumina ceramics, hydroxy apatite ceramics, titanium, methylmethacrylate, Sugita aneurysm clip, silicon shunt tube and lyophilized human dura mater (Lyo-dura). Both alumina ceramics and hydroxy apatite ceramics showed an excellent tissue compatibility in-vivo experiments. Although alumina ceramics showed an excellent tissue compatability in in-vitro experiments, hydroxy apatite ceramics showed less compatibility. Methylmethacrylate prepared one week before the experiment showed excellent compatibility, but the same material prepared at the time of experiment showed only fair compatibility. The titanium and silicon shunt tube showed excellent compatibility. The Sugita aneurysm clip, made from elgiloy, showed fair compatibility, while Lyo-dura showed excellent compatibility in in-vitro experiments, but less compatibility in in-vivo experiments. The reasons for the differences between the results of in-vivo and in-vitro experiments are discussed.

Animals↗
PubMed1983

Studies of polyarthritis caused by Mycoplasma arthritidis in rats. I. Detection of the persisting Mycoplasma antigen by the enzyme immune assay (EIA) and conventional culture technique.

Investigations on Mycoplasma (M.) arthritidis polyarthritis of the rat produced by intravenous inoculation of M. arthritidis ISR 1 with special reference to the persistence of the inoculated mycoplasma antigen were performed in a total of 145 rats. The mycoplasmas were demonstrated by the conventional culture technique as well as by an enzyme immune assay (EIA). M. arthritidis was cultured from liver, kidney, spleen, and thymus up to 4 days, from trachea and uterus up to 4 weeks, and from lung, heart, brain, and lymph nodes up to 2 months after infection. It could be recovered from the joints in 70-80% of the animals up to 28 days and in the remaining 20-30% up to 200 days after infection. Using the EIA the mycoplasmal antigen could be demonstrated generally, also in the joints of infected rats which had no longer been positive by culture (10-20 weeks after inoculation). The investigations using EIA also showed a positive reaction between antiserum against M. arthritidis and joint homogenates of control rats, indicating the presence of common antigens to M. arthritidis and to joint tissues of the rat.

Animals↗