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Biomedical subjects

A Islam

Publications and source records attributed to A Islam.

At least 127 records · Page 7Linked to original sources
PubMed1985

Haemopoietic stem cell: a new concept.

It is generally accepted that morphologically recognizable bone marrow (BM) cells are derived from progenitor cells committed to a specific line of haematopoietic differentiation [51]. The origin and morphological identity of such progenitor cells is not yet known and the question, whether there is a single pluripotent haematopoietic stem cell (HSC) or a variety of stem cells each with a capacity of self-replication and maintenance is still unresolved [37]. Although progress has been made in segregating [43, 47, 49, 64] various progenitor cells from one another and functional assays [11, 17, 42] have significantly promoted the study of haemopoietic precursor cells, morphological investigations were less rewarding. Even after enrichment, the morphology of haemopoietic stem- and colony-forming cells only remained hypothetical, 'candidate stem cells' [3], because their precursor cell qualities could not be deduced from their morphology, but only retrospectively, and statistically from their function, i.e. in vitro colony-formation or in-vivo haemopoietic reconstitution from an enriched cell suspension [58]. We postulate from our studies on semi-thin sections of undecalcified BM from healthy human fetuses, normal adults and patients with acute myeloid leukaemia (AML) and chronic granulocytic leukaemia (CGL) that the endosteal cells are the precursors of all haematopoietic cells in the bone marrow and are also capable of transformation into either stromal (fibroblast-like cells) or bone-related cells (osteoblasts and osteoclasts).

Bone Marrow↗
PubMed1985

Chronic granulocytic leukaemia: a defect in cellular interactions between stromal and haemopoietic stem cells?

Chronic granulocytic leukaemia (CGL) is regarded as a myeloproliferative disorder; in the chronic phase, the disease is characterized by excessive proliferation of myeloid cells apparently in the absence of any physiological demand. The reason(s) why and how this purposeless proliferation of myeloid cells begins remains to be elucidated. Recent studies on cellular interaction between stromal and haemopoietic stem cells (HSC) suggests that the stromal cells exert some form of regulatory influence on the growth and differentiation of HSC. In this communication it is postulated that CGL may be the result of a defect in cellular interactions between the stromal and haemopoietic stem cells.

Animals↗
PubMed1985

Plastic embedding in routine histology. I: Preparation of semi-thin sections of undecalcified marrow cores.

The preparation of sections of bone marrow cores in a routine histology laboratory requires decalcification and paraffin embedding, which produces shrinkage and considerable loss of cellular detail. This may be avoided by using plastic embedding procedures. This report describes a simplified routine procedure for using methylmethacrylate as a plastic embedding medium for the preparation of semi-thin sections of undecalcified bone marrow cores. A modification of the May-Grunwald-Giemsa stain is also given which provides good colour differentiation of various haematopoietic cells in the marrow. The method is simple, reproducible, requires no expensive equipment, and is suitable for routine processing of bone marrow biopsy cores in any histopathology laboratory.

Bone Marrow Examination↗
PubMed1985

Bone marrow biopsy changes in acute myeloid leukaemia. I: Observations before chemotherapy.

Pretreatment bone marrow trephine biopsy sections (BMB) from 34 patients with acute myeloid leukaemia (AML) were studied in parallel with bone marrow aspiration smears and peripheral blood films. In four cases marrow aspiration was inadequate and in five cases it was unsatisfactory. In two other cases hypoplastic AML was diagnosed, the aspirate in one suggested hypercellularity and in another it was unsatisfactory. Trephine biopsy was superior to aspiration for the evaluation of fat and marrow cellularity, pattern and extent of blast cell infiltration, homogeneity of the leukaemic infiltrate, frequency of mitoses, residual haemopoietic activity and presence of inflammatory cells. Of the various features studied in the sections, the presence of an increased number of plasma cells and considerable myelodysplasia (MD) appeared to be unfavourable prognostic features. We conclude that trephine biopsies are essential for the diagnosis of hypoplastic AML and are most useful when marrow aspiration is either inadequate or unsatisfactory. They also provide additional information about the bone marrow changes in AML and suggest that some histological features may also have prognostic significance.

Biopsy↗
PubMed1984

Histomorphological study of cellular interactions between stromal and haemopoietic stem cells in normal and leukaemic bone marrow.

The interactions between haemopoietic and stromal elements are crucial for stem cell proliferation and differentiation. The bulk of this evidence is derived from experiments in rodents and in-vitro culture studies. We have studied the spatial relationships between the stromal and haemopoietic components and their cellular composition in histological sections of bone marrow (BM) from seven healthy fetuses, 10 normal adults and over 60 patients with acute myeloid leukaemia (AML) and chronic granulocytic leukaemia (CGL) at different stages of the disease. During the early developmental stage (16-18 weeks) fetal BM showed focal haemopoiesis with a characteristic spatial localization of haemopoiesis near bony trabeculae and around small blood vessels. In AML following the treatment-induced hypoplasia, large uniform unilocular fat cells arranged in groups designated 'structured fat' developed from scattered multilocular precursor fat cells. Early foci of haemopoietic regeneration were present almost exclusively in areas of structured fat. In the marrow of patients with CGL in blast transformation (BT) treated by intensive therapy and autografting with cryopreserved haemopoietic stem cells, the haemopoiesis was focal. Clusters of regenerating erythroid precursors or of megakaryocytes were seen in intimate contact with marrow sinusoids and granulopoietic precursors in intimate association with small blood vessels and also in close contact with the endosteal surface of bony trabeculae. We conclude that the endosteal cells, fat cells and the vascular endothelial cells comprise the critical non-haemopoietic stromal elements of human BM. The close associations observed between the regenerating haemopoietic cells and the stromal cells provide strong evidence in support of the existence of a permissive haemopoietic micro-environment in man and emphasize the structural and functional interrelationships that exists between bone, fat, the microvascular system and haemopoiesis in human bone marrow.

Adult↗
PubMed1984

Bone marrow fibre content in acute myeloid leukaemia before and after treatment.

Bone marrow fibre content was studied in 34 patients with acute myeloid leukaemia at presentation and subsequently after chemotherapy and at complete remission. The findings indicate that: some degree of marrow fibrosis is present in about one third of the patients with acute myeloid leukaemia at presentation; effective antileukaemia treatment may result in reversal of marrow fibrosis; and increase in marrow fibre content at diagnosis does not affect haemopoietic regeneration after treatment and achievement of complete remission.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Giardia lamblia infections in a cohort of Bangladeshi mothers and infants followed for one year.

Giardia lamblia infection in an endemic area was investigated by following a cohort of 33 lactating mothers and their infants in a semiurban community of Bangladesh for one year. Eighty-two percent of mothers and 42% of infants excreted Giardia at least once during the study period. Infants became infected as early as 3 months of age, and 86% of the infected infants had diarrhea, suggesting that the first exposure to the parasite results in disease. Only one of the infected mothers had diarrhea, indicating that with repeated exposure to Giardia, mothers in an endemic area may develop partial immunity that protects against disease but not infection. An interrelationship between maternal and infant colonization was not found. Local and systemic immune responses to Giardia correlated poorly with infection, but milk antibodies were a better reflection of infection than serum antibodies were. Infection with G. lamblia was significantly lower in infants younger than 6 months (9%), an age when many are totally breast-fed. However, we were unable to establish clear-cut protection related to human milk antibodies, and suggest that the lower infection rate in younger infants results mainly from decreased exposure to Giardia cysts.

Adolescent↗
PubMed1982

The therapeutic community: a critical reappraisal.

Any new concept or movement can be understood only when considered in light of the sociopolitical context in which it emerges. The authors critically assess the concept of the therapeutic community in such terms. They assert that the therapeutic community should be viewed as a protest movement itself, or as part of a greater protest against the dehumanizing conditions of mental hospitals in the early 20th century. As a protest movement it has achieved significant success. However, the author say, its therapeutic value has yet to be conclusively demonstrated and its practicability is also highly questionable. The authors suggest that the therapeutic community should be reassessed in light of changed social conditions, and a new and more pragmatic approach to organizing psychiatric hospitals be formulated.

Humans↗
PubMed1981

Single-dose ampicillin therapy for severe shigellosis in Bangladesh.

To evaluate a more economical regimen for severe shigella dysentery, treatment with single-dose (SD) ampicillin (100 mg/kg) was compared in a randomized trial with results obtained in a conventional five-day (100 mg/kg per 24 hr) multiple-dose (MD) course. Clinical relapse occurred in one of 23 SD children, no SD or MD adults, and none of 18 MD children. Bacteriologic failures were observed in six of 26 adults compared with one of 24 MD adults (P = 0.05). Four of 10 SD children younger than four years of age failed bacteriologically, compared with one MD child. In SD children, lower ampicillin levels were significantly associated with bacteriologic failure and younger age. Resistance of Escherichia coli to ampicillin, although transiently less in SD patients, was equal in MD and SD patients two weeks after therapy. Thus, in highly endemic areas SD ampicillin is clinically effective therapy for ampicillin-sensitive shigellosis in patients older than four years of age.

Adult↗
PubMed1981

Histological study of the bone marrow in chronic granulocytic leukaemia in blast transformation. I. Serial observations before and after autografting.

Sixteen patients with chronic granulocytic leukaemia (CGL) in blast cell transformation (BT) were studied by means of serial bone marrow trephine biopsies (BMB). The BMB were performed during the following stages of the disease: 1 at diagnosis of BT, 2 following ablative therapy and 3 during haematological recovery following autografting. In 10 of the 16 patients, BT was recognized by the presence of a distinctive infiltration with blast cells with a single large hyperchromatic nucleolus. In four of the 16 patients, the diagnosis of BT could only be made by BMB since simultaneous marrow aspiration yielded either a dry tap or no marrow fragments; in two of these four patients the BT was focal in the BMB specimen. Following ablative therapy and during haematological regeneration after autografting, BM aspirates were unsatisfactory in most cases and they were inadequate to assess cellularity or the presence of residual blasts. In contrast, sections of BMB showed clearly whether a decrease in cellularity took place or, in some, residual blasts were still present. BMB samples obtained 2 weeks after autografting showed haemopoietic regeneration consisting of discrete foci of either erythroid, granulocytic or megakaryocytic precursor cells. We conclude that BMB is essential for diagnosing CGL in BT, for monitoring the progress of these patients after therapy and in assessing the haemopoietic regeneration following autografting.

Blood Transfusion↗
PubMed1981

Histological study of the bone marrow in chronic granulocytic leukaemia in blast transformation. II. Bone marrow fibre content before and after autografting.

A serial study of the extent of bone marrow (BM) fibrosis was carried out in 14 patients with chronic granulocytic leukaemia (CGL) in blast transformation (BT) who received intensive treatment followed by autografts to restore marrow haemopoiesis. Some degree of marrow fibrosis (MF) was identified in 13 of the 14 patients when blast transformation was diagnosed. A transient increase in the amount of marrow fibrosis was observed in most cases immediately following intensive chemoradiotherapy or chemotherapy alone but this had regressed by 4-6 weeks when chronic phase haemopoiesis was established in the marrow. The presence of marrow fibrosis when blast transformation was diagnosed did not appear to impair the effectiveness of the autograft.

Antineoplastic Agents↗
PubMed1980

Oral therapy in children with cholera: a comparison of sucrose and glucose electrolyte solutions.

We performed a double-blind trial comparing sucrose electrolyte oral solution with glucose electrolyte oral solution in children less than 5 years of age with severe cholera-like diarrhea. Of 111 patients studied (102 with bacteriologically confirmed cholera), 55 received sucrose solution and 56 received glucose solution. The success rates, as defined by the absence of the need to give unscheduled intravenous therapy, were similar in the two groups (73% and 77% in the sucrose and glucose groups, respectively). There was no difference in purging rates between the two groups. The primary determinant of success for oral fluid regardless of the sugar was the purging rate. Sucrose malabsorption was responsible for oral therapy failure in one child. This study demonstrates that sucrose is an effective alternative to glucose in the oral therapy solution, but either must be used in conjunction with intravenous solution when treating severe dehydrating diarrhea.

Administration, Oral↗
PubMed1980

Haematological reconstitution after autografting for chronic granulocytic leukaemia in transformation: the influence of previous splenectomy.

Peripheral blood values and bone marrow appearances were monitored in eight patients treated for chronic granulocytic leukaemia in transformation by cytotoxic drugs with or without total body irradiation followed by autografting with cryopreserved-thawed peripheral blood nucleated cells. One of the patients was 'autografted' on two occasions. Five patients had been splenectomized early in the first chronic phase and the other three patients had their spleens intact. Recovery of peripheral blood values was more rapid in the splenectomized than in the non-splenectomized patients. CFUc were present in the circulation immediately after autografting in each case but subsequently the pattern of CFUc changes differed between patients. The bone marrow was hypocellular at the time of autografting but the rate at which it returned to a typical chronic phase picture varied. Peripheral blood nucleated cells collected at the time of diagnosis include stem cells with the capacity to repopulate the marrow after 'ablative' therapy for transformation. Elective splenectomy in the chronic phase may promote more rapid recovery of peripheral blood values but its long-term importance is unknown.

Blood Transfusion, Autologous↗