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Biomedical subjects

A Islam

Publications and source records attributed to A Islam.

At least 37 records · Page 2Linked to original sources
PubMed1993

Vocal affect in three-year-olds: a quantitative acoustic analysis of child laughter.

Recordings were obtained of the laughter vocalizations of four 3-year-old children during three sessions of spontaneous free-play between mother and child in a laboratory playroom. Acoustic analysis was used to determine laughter durations, laughter events, F0, and harmonic characteristics, and to suggest a taxonomy of laughter types. Melodic contours were assessed from patterns of F0 change during laughter. Mean duration of laughs ranged from 200 ms to 2.0 s, but events within a laugh were usually about 200-ms duration. Laughs were intuitively classified into four major types, and, following the acoustic analyses, were further defined and classified into types and subtypes of exclamatory and dull comment; chuckle; basic, variable, and classical rhythmical; and squeal. Melodic contours included more rising contours than previously reported for cry, but there was great variability in the types of contours produced especially for rhythmical laughs. The results of the acoustic analyses are discussed in relation to (a) the development of a taxonomy of laughter and (b) different features of the vocal affect characteristics of high-intensity emotion.

Child Behavior↗
PubMed1993

Treatment of typhoid fever with ceftriaxone for 5 days or chloramphenicol for 14 days: a randomized clinical trial.

To compare the therapeutic efficacy of ceftriaxone given once daily for 5 days and chloramphenicol given four times daily for 14 days, a controlled trial was carried out with 59 patients who were culture positive for Salmonella typhi. Ceftriaxone was given to 28 patients in once-daily intravenous doses of 75 mg/kg of body weight to children and 4 g to adults for 5 days; chloramphenicol was given to 31 patients at a dosage of 60 mg/kg/day until defervescence and then at 40 mg/kg/day to complete 14 days of treatment. All Salmonella isolates were susceptible to both antibiotics. Clinical cures (defervescence without complications, no relapse, and no need for further treatment) occurred in 79% of the patients treated with ceftriaxone and 90% of those treated with chloramphenicol (P = 0.37). On the third day of treatment, blood cultures were positive for S. typhi for 60% of the patients in the chloramphenicol group and 0% of the ceftriaxone group (P = 0.001). Defervescence occurred in half the patients in both groups during the first 7 days, but on days 9 to 13 after the start of treatment, nine patients in the ceftriaxone group, compared with six patients in the chloramphenicol group, remained febrile (P = 0.4). The median hematocrit and total leukocyte counts at day 14 were significantly lower for the chloramphenicol group than those for the ceftriaxone group (P = 0.01 and P = 0.02, respectively). These results indicate that the effects of therapy with ceftriaxone for typhoid fever differed from those of chloramphenicol therapy in that blood cultures became negative earlier, prolonged fever persisted in some patients, and bone marrow suppression was reduced. We conclude that a short, 5-day course of ceftriaxone is a useful alternative to conventional 14-day chloramphenicol therapy in the treatment of typhoid fever.

Adolescent↗
PubMed1993

Abnormal norepinephrine metabolism in rat brain synaptosomes in phosphate depletion.

Abnormalities in the function of the central nervous system exist in phosphate depletion (PD). It is possible that this is due to an adverse effect of PD on the metabolism of neurotransmitters, such as norepinephrine (NE), in brain synaptosomes. We examined the effects of PD, produced by restriction of dietary phosphate intake on NE metabolism of brain synaptosomes. Synaptosomes from PD rats had significantly reduced NE content, uptake and release, elevated Km, but normal Vmax of tyrosine hydroxylase, normal Km and Vmax of monoamine oxidase, elevated resting levels of cytosolic calcium ([Ca2+]i), higher delta [Ca2+]i in response to KCl, higher delta [Ca2+]i/basal [Ca2+]i ratio, lower ATP content and reduced activity of Na(+)-K(+)-ATPase as compared to synaptosomes from pair-weighed rats. Treatment of PD rats with verapamil corrected all the synaptosomal derangements except for the elevated Km of tyrosine hydroxylase and NE content. Verapamil did not affect the metabolism of PW rats. The data demonstrate that PD causes significant derangements in NE metabolism of brain synaptosomes. Observations in the present study and in others indicate that these derangements in NE metabolism are due to the PD-induced abnormalities in the homeostasis of synaptosomal [Ca2+]i, ATP and phospholipids and in the activities of Na(+)-K(+)-ATPase and Ca(2+)-ATPase.

Animals↗
PubMed1993

Common diarrhea pathogens and the risk of dehydration in young children with acute watery diarrhea: a case-control study.

The role of common diarrheal pathogens in dehydration was examined in children with acute watery diarrhea who attended the treatment center of the International Centre for Diarrhoeal Disease Research, Bangladesh, in Dhaka. Two hundred sixty-nine children with moderate or severe dehydration were matched with 700 children with no dehydration. Vibrio cholerae O1 infections were 5.5 times more likely to be associated with dehydration than in cases without this agent. No significant association could be found between the presence of enterotoxigenic Escherichia coli. Campylobacter jejuni, or rotavirus infection and dehydration. These results were obtained after simultaneously controlling for age, lack of oral rehydration therapy (ORT) at home, protein energy malnutrition, withdrawal of breast-feeding during diarrhea at home, poor housing, longer duration of diarrhea at home, and delay in reaching the treatment center. The cholera isolation rate was only 4.5% and thus explains only a small proportion of the cases of dehydration. In cholera-endemic areas, a strategy to prevent dehydration in small children is needed to ensure correct use of ORT at home, prompt referral, and the use of a suitable antibiotic when cholera is clinically suspected.

Acute Disease↗
PubMed1993

Systemic allergic reaction and diarrhoea after pineapple ingestion.

Some foods may initiate allergic reactions. Anaphylaxis due to mangoes, oranges, nuts and other foods has been reported earlier. We report the clinical and laboratory features of 32 patients who became symptomatic shortly after they had eaten pineapples. Seventeen patients were males and 15 females with ages ranging from 5 to 70 years. Most of the patients complained of intense itching and urticarial rashes, followed by abdominal pain, vomiting and diarrhoea. Sixty-eight percent of the patients became symptomatic within half an hour of eating the pineapple. On examination 18 patients had an urticarial rash and a flushed face. Although none of the patients were severely dehydrated, 20 patients presented with shock. Their peripheral pulse and blood pressure were low or absent suggesting an anaphylactoid reaction. The median total eosinophil count was 1850 (250-6375/mm3). The serum IgE level measured in 4 patients was raised. The patients were treated with intravenous fluids and antihistamine. Some patients also received steroid and adrenaline. All patients recovered uneventfully. Our findings suggest that ingestion of pineapple may occasionally cause an anaphylactoid reaction.

Adolescent↗
PubMed1992

Endothelial cells and hematopoiesis: a light microscopic study of fetal, normal, and pathologic human bone marrow in plastic-embedded sections.

The origin and morphological identity of hematopoietic progenitor cells, as well as their precursor, the pleuripotential hematopoietic stem cell (HSC), has not been established. Our studies of 2 microns sectioned undecalcified plastic-embedded bone marrow (BM) from healthy human fetuses; normal adults; patients with acute myeloblastic leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic granulocytic leukemia (CGL) in various stages (chronic, accelerated, acute blastic phase, and after autografting); and patients recovering from therapy-induced marrow hypoplasia suggest that proliferative hematopoietic zones exist near the endosteum (endosteal marrow) and the vascular endothelium (capillary and sinus-lining endothelium) and a maturational zone distal to these regions. In some of these areas, morphologically recognizable hematopoietic cells were seen and interpreted as emerging and maturing in a sequential progression, suggesting an origin from the endosteal or endothelial progenitors. In other loci, early hematopoietic cells were seen in close contact with the endosteal or vascular endothelial (VE) cells. This latter relationship suggested that these areas of cellular contact were important and represented sites of cell to cell interaction that may be associated with the liberation of growth factors by endosteal and endothelial cells and their action on hematopoietic progenitor cells. Following treatment-induced hypoplasia, the endosteal and VE cells were seen to modulate, transform, and migrate into the surrounding empty and edematous marrow space as fibroblasts. Later, as hemopoietic regeneration began, clusters of regenerating hematopoietic cells were seen adjacent to bone trabecule (BT) and near the vascular endothelium. We postulate that endosteal and VE cells are the equivalent of embryonal-stage, undifferentiated mesenchyme and, under the appropriate regulatory influence, are capable of modulation and transformation (differentiation) into stromal (fibroblast-like) cells and precursors of hematopoietic cells in normal (physiologic) and stressed (pathologic) conditions. Recently, human endothelial cells have been shown to express a large number of cell surface antigens in common with hematopoietic (myeloid and lymphoid) cells. It is also possible that, in some situations, the VE cells act to establish a microenvironment and liberate growth factor(s), enabling pleuripotential and progenitor cell differentiation into mature hematopoietic cells adjacent to the vascular endothelium. Indeed, vascular endothelium has been shown to elaborate growth factors that participate in normal hematopoiesis.

Adult↗
PubMed1992

The origin and spread of human leukemia.

The human leukemias are a group of hematologic neoplasms characterized by uncontrolled proliferation of cells concerned with blood cell production. The cause(s) of human leukemia remains unknown. Bone marrow (BM) is believed to be the site of origin of human leukemias, although the specific locus(i) and/or cell(s) from which it arises have not been definitively identified. Generally, human leukemias and related proliferative diseases are thought to be clonal in nature; affecting a single hematopoietic stem cell, which then proliferates and replaces the marrow of normal hematopoietic stem cell systems. The condition is believed to be malignant in nature. Results of our current morphologic studies on well-fixed, ideally-stained thin sections of plastic-embedded bone marrow biopsies (BMB) from a large number of acute (AML, ALL) and chronic (CGL, CLL) leukemia patients suggest that human leukemias may not be clonal diseases. Instead, a large population of other resident cells--'endosteal cells'--appears to become involved in the process and it is possible that all members of this group enter the activity simultaneously. This change (transformation) in the endosteal cell population might be due to an abnormality (qualitative or quantitative) of diffusable, humoral factors (yet to be identified) that are responsible for the growth and proliferation of these hematopoietic precursor cells. In this context, the human leukemias may be considered not as malignant, but rather the result of an aberration of factor(s) that control hematopoiesis. In this respect, the human leukemias, particularly AML, ALL and CML, might be analogous to pernicious anemia (megaloblastic anemia) as it was understood 40-50 years ago.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow↗
PubMed1992

Breast feeding and oral rehydration at home during diarrhoea to prevent dehydration.

In a case-control study we evaluated the role of maternal behaviour, as reflected in maintenance of breast feeding and the use of oral rehydration therapy (ORT) at home during acute diarrhoea, in preventing dehydration in infants and young children. A systematic 5% sample was taken of all children aged 1-35 months attending the treatment centre of the International Centre for Diarrhoeal Disease Research, Bangladesh, with acute watery diarrhoea of six days or less between August 1988 and September 1989. There were 285 children with moderate or severe dehydration as cases and 728 with no dehydration as controls in the study. In a multivariate analysis using a logistic regression model we showed that withdrawal of breast feeding during diarrhoea was associated with a five times higher risk of dehydration compared with continuation of breast feeding during diarrhoea at home. Lack of ORT with either complete formula or a salt and sugar solution at home was associated with 57% higher risk of dehydration compared with receipt of a reasonable amount of ORT after controlling for several confounders. The confounding variables--that is, lack of maternal education, history of vomiting, high stool frequency, young age and infection with Vibrio cholerae 01--were also shown to be risk factors of dehydration. Health education programmes should promote continued breast feeding and adequate oral rehydration therapy for infants with acute diarrhoea at home.

Bangladesh↗
PubMed1992

Effect of chronic renal failure with and without secondary hyperparathyroidism on the activities of synaptosomal tyrosine hydroxylase and monoamine oxidase.

Norepinephrine (NE) content, release and uptake by brain synaptosomes are reduced in chronic renal failure (CRF), and this has been attributed to the state of secondary hyperparathyroidism. The decrease in NE content in CRF could not be explained by changes in NE uptake or release since in normal circumstances, NE content usually remains unchanged despite fluctuation in NE uptake and release. Since NE content is determined by its production and degradation, we examined the effect of CRF with and without excess parathyroid hormone (PTH) on the Michaelis-Menton constant (Km) and Vmax of tyrosine hydroxylase (TH), the rate-limiting enzyme for NE production, and monoamine oxidase (MAO), an enzyme involved in NE degradation of brain synaptosomes. Brain synaptosomes from rats with a 21-day CRF have a significantly (p less than 0.01) lower Vmax of TH (39.5 +/- 5.3 pmol tritiated H2O/mg protein/min) than that of normal rats (61. +/- 7.5 pmol tritiated H2O/mg protein/min) and a higher Km of MAO (59 +/- 2.9 nM tyramine) than normal animals (46 +/- 1.7 nM tyramine). Parathyroidectomy (PTX) in CRF rats normalized Vmax of TH (54 +/- 4.5 pmol tritiated H2O/mg protein) and Km of MAO (48.4 +/- 2.3 nM tyramine). Cytosolic calcium, [Ca2+]i, in brain synaptosomes is significantly (p less than 0.01) higher in rats with CRF (488 +/- 8.5 nM) than in normal (355 +/- 6.0 nM) or PTX-CRF (360 +/- 8.1 nM) rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Dietary risk factors associated with acute and persistent diarrhea in children in Karachi, Pakistan.

Feeding practices may have an important impact on diarrheal diseases in developing countries. This study evaluated feeding practices in three groups of male children aged 6-36 mo: 100 with persistent diarrhea (PD), 79 with acute diarrhea (AD), and 86 in a comparison group (CG). The children came from comparably poor socioeconomic settings in Karachi, Pakistan, except that the literacy rates were higher in mothers of the CG (P = 0.0001). Although greater than 95% of all infants were breast-fed, delayed initiation of breast-feeding was more common in the diarrhea groups. Children with diarrhea were also more likely to receive supplemental milk (PD = 92%, AD = 87%) than were children in the CG (69%, P less than 0.05). Feedings were not withheld during diarrhea but changes were made in the nature of foods given. These results indicate that several feeding practices may be important risk factors for diarrhea in Pakistan.

Acute Disease↗
PubMed1991

New sternal puncture needle.

The needles most commonly used for obtaining bone marrow aspirates from the sternum are the Salah and Klima needles. They were designed in the 1930s, and except for the introduction of different kinds of stops and guards there has been no change in their basic structure and design. These instruments are small, do not fit properly in the operator's hand, and the lack of a T-bar handle often makes them difficult to manoeuvre; their introduction into the sternum by twisting or rotary movement of the hand can be cumbersome. To overcome all of these disadvantages an instrument was designed which is larger, provides better grip, and offers improved maneuverability. The stilette of this aspiration needle has a domed handle which rests snugly in the operator's hand and affords operator comfort, while the specially shaped large T-bar handle at the proximal end of the needle provides adequate and firm grip and also ensures precise control during the sternal puncture procedure.

Biopsy, Needle↗
PubMed1991

Reduced phospholipid contents of brain synaptosomes in phosphate depletion.

The effects of 6 wk phosphate depletion (PD) and pair-weight feeding (PW) without and with treatment with verapamil (PD-V and PW-V, respectively) on phospholipid (PL) and cholesterol content and on resting levels of cytosolic calcium concentration ([Ca2+]i) of brain synaptosomes of rats were examined. PD was associated with significantly (P less than 0.01) lower synaptosomal content of total PL, phosphatidylinositol (PI), phosphatidylserine (PS), and phosphatidylethanolamine (PE) and with significant (P less than 0.01) elevation in [Ca2+]i. Verapamil treatment of PD rats prevented the rise in [Ca2+]i of brain synaptosomes and the fall in PI and caused significant (P less than 0.01) improvement in the synaptosomal content of PS and PE; values of PS and PE in PD-V rats, however, were still significantly (P less than 0.01) lower than those of PD rats. Verapamil treatment of PW rats did not affect synaptosomal content of the various PL or resting levels of [Ca2+]i. Cholesterol content of brain synaptosomes of the various groups was not significantly different, but cholesterol-to-total PL ratios were significantly (P less than 0.01) higher in PD and PD-V rats than in PW or PW-V animals. Results indicate that PD affects metabolism of total phospholipids, PI, PS, and PE of brain synaptosomes, and these derangements are due to reduced availability of phosphorus and to the rise in [Ca2+]i. The data are consistent with the proposition that PD-induced changes in PL render the synaptosomal membrane more permeable to calcium, an event that may lead to a rise in [Ca2+]i.

Animals↗
PubMed1991

A traditional diet as part of oral rehydration therapy in severe acute diarrhoea in young children.

Recently, the role of feeding as treatment of acute diarrhoea has received increasing attention. To assess the efficacy of early feeding in acute diarrhoea, we conducted a randomised, clinical trial of a traditional legume-based weaning diet khitchri in boys 9 to 48 months old with moderate to severe dehydration. Khitchri is composed of rice and lentils cooked with cottonseed oil. Children were randomly allocated to 2 groups: group A received only WHO ORS but no food for the first 24 hours and then khitchri and half-strength cow's milk formula freely; group B received khitchri and the half-strength formula in addition to ORS after the initial rehydration period of 4 to 6 hours. The mean period of evaluation was 3 days. 69 patients were admitted into the study, 33 in group A and 36 in group B. The initial mean purging rate for the children was greater than 200 g/kg/day. Six children did not complete the study because they developed intercurrent infections or were removed by their parents for non-medical reasons. Of the 63 patients who were evaluated, 44 (70%) were successfully treated, 21 in group A and 23 in group B. There were no significant differences in the 2 groups in mean stool output, number of stools, or weight gain, although a trend toward earlier improvement was seen in group B. These data indicate that early feeding of khitchri and WHO/ORS may be as well tolerated as WHO/ORS alone in the first 24 hours treatment of severe acute diarrhoea in young children.

Acute Disease↗
PubMed1990

Bone lining (endosteal) cells and hematopoiesis: a light microscopic study of normal and pathologic human bone marrow in plastic-embedded sections.

Human trabecular bone that encloses the bone marrow (BM) is covered by a single layer of thin, sometimes inconspicuous, flat, elongated (spindle-shaped) endothelium-like cells with a round or oval nucleus. These "bone lining" cells, or endosteal cells (EC), form a continuous membrane (endosteum) over the trabecular bone surfaces. In most cases, the composition and thickness of these cells do not vary unless the cells are in intimate contact with hematopoietic tissue. In that instance, they are seen as a single layer adjacent to hematopoietic tissue or as a zone of tightly packed or loosely arranged mononuclear (hematopoietic) cells, some apparently originating from the endosteum. In a reparative process, such as following BM harvest, during which bony trabeculae (BT) are mechanically fractured, these cells are seen giving rise to osteoprogenitor (osteoblasts and osteoclasts) cells. Occasionally, the EC appear similar to BM stromal cells (morphologically and by their association with collagen/reticulin fibers) and are best seen at or near the BT that are cut tangentially. Short processes extending from the EC towards the underlying osteocytes have also been observed, suggesting that a channel of communication exists between them and osteocytes. Our observations, coupled with the experimental findings of others (i.e., that hematopoietic stem cells are concentrated near the endosteum, that cells responsible for BM and stroma regeneration are derived from the endosteal layer, and that high concentrations of hematopoietic colony-stimulating factors are produced there), indicate that, in addition to functioning as a simple membranous covering layer for BT, the endosteum helps to support osteocytes and maintains mineral homeostasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Marrow↗
PubMed1990

Sea snake (Microcephalophis gracilis) hemoglobin: primary structure and relationships to other forms.

The hemoglobin of the sea snake Microcephalophis gracilis was purified and the primary structure of the alpha and beta chains determined. This is the first sea snake hemoglobin structure characterized, and apparently also the first complete structure of any snake hemoglobin (an alpha chain of a viper was known), allowing judgments of reptilian variants. Variations between the sea snake form and other reptilian forms are large (52-65 differences for the alpha chains), of similar order as those between the sea snake and avian (56-65 differences) or human (58 differences) forms. Functionally, 19 residues at alpha/beta contact areas and 7 at heme contacts are exchanged in relation to the human alpha and beta chains. Four positions of the sea snake hemoglobin contain residues thus far unique to this form. However, all replacements appear compatible with conserved overall functional properties.

Amino Acid Sequence↗