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Biomedical subjects

L Morris

Publications and source records attributed to L Morris.

At least 19 recordsLinked to original sources
PubMed1992

Changes in the precursor frequencies of IL-4 and IFN-gamma secreting CD4+ cells correlate with resolution of lesions in murine cutaneous leishmaniasis.

Limiting dilution analysis was used to estimate the frequency of clonogenic Ag-specific CD4+ T lymphocytes in draining lymph nodes of mice over the course of infection with Leishmania major, and to measure the production of IL-2, IL-3, IL-4, IFN-gamma, and TNF by the resultant clones. Infection of both genetically susceptible BALB/c ("non-healer") and resistant C57BL/6 ("healer") mice resulted in at least a fourfold increase in the frequency (to about 0.3%) and at least a 10-fold increase in the total number of lymph node CD4+ cells that formed clones when cultured with L. major Ag in vitro. At 1 wk after infection, the majority of clones from BALB/c mice secreted IL-4 (precursor frequency 0.15%) and fewer secreted IFN-gamma (0.05%); this pattern remained constant for at least 8 wk after infection. In C57BL/6 mice, however, a high precursor frequency of IL-4-secreting clones was measured in the first 1 to 2 wk when the mice had lesions, but resolution of infection was associated with a decrease in the frequency of IL-4-secreting clones (from 0.13% at 2 wk to 0.03% at 4 wk) and an increase in the frequency of IFN-gamma-secreting clones (from 0.08% to 0.22%). At all stages of infection, most clones from either mouse strain secreted IL-3 and very few secreted TNF. Analysis of PCR-amplified cDNA from draining lymph nodes of infected mice also revealed that IL-4 and IFN-gamma mRNA were expressed in both mouse strains early in infection. IL-4 mRNA was the major species at 2 and 6 wk after infection in BALB/c mice, but declined relative to IFN-gamma mRNA over this time in C57BL/6 lymph nodes. Precursor frequency estimates of lymphokine-secreting CD4+ cells in draining lymph nodes therefore correlated with lymphokine expression patterns in vivo. Analysis of a panel of individual short term clones derived from mice 1 wk after infection revealed marked heterogeneity in lymphokine production patterns. In BALB/c mice, 49% secreted IL-4 without IFN-gamma, 18% secreted IFN-gamma without IL-4, and 14% secreted both IL-4 and IFN-gamma. Similarly in C57BL/6 mice, 39% secreted IL-4, 20% secreted IFN-gamma, and 17% secreted both lymphokines. Many of the clones also produced IL-3 and/or IL-2. Together the data suggest that both IL-4 and IFN-gamma are synthesized early in infection of susceptible and resistant mice as assessed by mRNA and precursor frequency analyses.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1992

Sexual experience and use of contraception among young adults in Latin America.

Although a formal public health surveillance system has not yet been established in Latin America to document the attitudes of young people toward sex education, sexual activity, and contraception and their behaviors in these areas, representative data are available from 12 household-based Young Adult Reproductive Health Surveys conducted in seven countries since 1985. The surveys indicate that the rate of sexual experience before marriage or consensual union for males is much higher than that for females, and first sexual experience occurs at a younger age for males than for females. However, from 34% to 90% of females 20-24 years of age report having had premarital sexual relations. No more than 41% of females and 31% of males report that they or their partner used contraception at first sexual experience. Less than one-third of both young men and young women could identify the most fertile period during the menstrual cycle. The results of such surveys have provided program officials and policymakers with data to plan, implement, and evaluate interventions targeted for young adults.

Adolescent↗
PubMed1992

Alternative histochemical markers for skeletal muscle capillaries: a statistical comparison among three muscles.

Except in thin muscles, the analysis of muscle capillary depends on direct ultrastructural visualization or histochemical identification of the capillaries using stains for basement membrane or reactions for endothelial cell enzymes. The accuracy of existing histochemical methods for detecting capillaries has not been systematically tested, however. The purpose of the present study was to compare muscle capillarity determined by two methods currently in use, Griffonia simplicifolia I lectin (GSI) and ATPase, with two alternative capillary markers, Lycopersicon esculentum lectin (LEA) and MRC OX.43 antigen. Capillarity, expressed as capillaries around fibers (CAF), was determined in the soleus, extensor digitorum longus, and sternomastoid muscles from 4-month-old female rats. The GSI, LEA, and MRC OX.43 capillary markers gave identical results for each muscle, confirming their validity as cytochemical probes. In contrast, the capillary ATPase method gave significantly lower CAF determinations, with a differential effect of preincubations at pH 4.4 vs 4.0. These data suggest that capillary ATPase acid stability varies within the capillary bed. The use of one or more of the alternative capillary markers tested is suggested for studies of muscle capillarity to confirm that binding sites or enzyme activity used for a given probe is expressed under both control and experimental conditions.

Adenosine Triphosphatases↗
PubMed1992

Blue rubber bleb nevus syndrome: laser photocoagulation of colonic hemangiomas in a child with microcytic anemia.

This is a case report and review of the literature on the blue rubber bleb nevus syndrome. The clinical features of the syndrome are discussed, with emphasis on chronic gastrointestinal bleeding and resulting anemia. A new therapeutic modality, colonoscopy with laser photocoagulation, is recommended as a safe, effective, and less invasive method of controlling bleeding from colonic hemangiomas than surgical resection and repeated transfusions. This technique is less helpful for patients with prominent involvement of the small intestine.

Anemia↗
PubMed1992

Developmental regulation of sialoadhesin (sheep erythrocyte receptor), a macrophage-cell interaction molecule expressed in lymphohemopoietic tissues.

Stromal macrophages in lymphohemopoietic tissues express novel macrophage-restricted plasma membrane receptors involved in nonphagocytic interactions with other hemopoietic cells. One such receptor with lectinlike specificity for sialylated glycoconjugates on sheep erythrocytes and murine hemopoietic cells has been characterized immunochemically and termed sialoadhesin. We have examined sialoadhesin expression during mouse development to learn more about its regulation and function. Immunocytochemical, rosetting, and Western blot studies show that sialoadhesin is first detected on fetal liver macrophages on day 18 of development, 7 days after numerous F4/80+ macrophages are found within erythroblastic islands. In spleen and bone marrow, sialoadhesin appears between day 18 and birth, in parallel with myeloid development. Strongly labeled macrophages in the marginal zone of spleen, characteristic of adult lymphoid tissues, appeared gradually between 1-4 weeks after birth, as the white pulp became enlarged. Isolation of fetal liver macrophages at day 14 confirmed that sialoadhesin was not involved in the binding of erythroblasts, which is mediated by a distinct cation-dependent receptor (Morris et al., 1988, p. 649). Sialoadhesin could be expressed by isolated fetal liver macrophages after cultivation in adult mouse serum, a known source of inducer activity, but was not dependent on the presence of this inducer, unlike adult-derived macrophages. Fetal plasma contained inducing activity on day 13, but adult levels were not reached until 2 weeks postnatally. These studies show that sialoadhesin is differentially regulated compared with the erythroblast receptor and F4/80 antigen, that it is not required for fetal erythropoiesis, and that its induction on stromal macrophages is delayed until the onset of myeloid and lymphoid development. Sialoadhesin provides a marker to study maturation and functions of macrophages during ontogeny of the lymphohemopoietic system.

Animals↗
PubMed1992

Neuropsychological functioning of first-episode schizophreniform patients.

OBJECTIVE AND METHOD: This study compared 32 consecutively admitted first-episode schizophreniform patients, 26 patients with chronic schizophrenia according to the DSM-III-R criteria, and 25 normal comparison subjects on a comprehensive battery of neuropsychological tests to determine the degree of cognitive impairment existing at the onset of schizophrenic illness. Patients were tested within 2 weeks of admission to the hospital, after their medication had been stabilized. RESULTS: With age and education controlled, the first-episode and chronic patients performed significantly worse than the normal subjects on neuropsychological summary measures of executive function, verbal memory, spatial memory, concentration/speed, and global cognitive function and on left and right hemisphere function scales. The first-episode patients were as cognitively impaired as the chronic patients on all summary scales and many of the individual tests. Both groups showed relatively greater left than right hemisphere dysfunction. CONCLUSIONS: These findings suggest that substantial cognitive deficits, comparable to those of chronic patients, are present early in the course of psychotic illness.

Adult↗
PubMed1992

[Reproductive health survey of young adults in greater Santiago].

In 1988 a survey was carried out in order to obtain information on knowledge about reproduction, sexual activity, attitudes, and use of contraceptive methods among residents between 15 and 24 years of age in Greater Santiago. For this purpose, a multistage, self-weighted, non-replacement probability sample was chosen from the entire Santiago urban area. After 2,898 households were visited, 865 women and 800 men were selected and interviewed. For the interview, a questionnaire with 156 questions was developed; many questions were similar to those included in similar surveys in Brazil and Guatemala. The interviewers were professionals who had received prior training. Although 75% of the interviewees had attended sex education classes, they had erroneous ideas on various basic subjects. Sixty-nine percent of the women interviewed had undergone menarche before attending these classes. In addition, 35.4% of the women and 65.0% of the men had had sexual relations prior to marriage, and less than 20% had used any contraceptive method. More than 60% of the interviewees who had children had conceived them before marrying. These findings point up the necessity of offering sex education classes for children and young people, as well as facilitating their access to family planning services, in order to decrease the number of illegitimate and unwanted children that are born in Chile.

Acquired Immunodeficiency Syndrome↗
PubMed1992

A new, sensitive polynucleotide probe for distinguishing Candida albicans strains and its use with a computer assisted archiving and pattern comparison system.

The repetitive DNA sequence poly[d(GT).d(CA)],(polyGT) can be used to generate DNA fingerprints that distinguish different yeast genera. In this study we demonstrate that the probe can also be used to distinguish individual strains of clinical isolates of Candida albicans. Isolates were fingerprinted by probing Southern blots of restriction enzyme-cleaved DNA samples with radioactively labelled polyGT. The discrimination between strains was clearer than can be achieved by direct visualization of ethidium bromide stained gels and was comparable to that achieved with previous DNA probes. However, the advantage of this probe is that it is not limited to Candida species since polyGT sequences appear to be ubiquitous in eukaryotes. Fingerprints were also generated from Southern blots using a commercial (AMBIS) radioanalytical imaging computer system. A proprietary software package (MICRO PM) was effective in discriminating between the C. albicans strains. These preliminary results indicate the potential value of this probe for discrimination between Candida isolates in epidemiological studies of candidosis.

Blotting, Southern↗
PubMed1991

Congenital ossifying fibroma (osteofibrous dysplasia) of the tibia--a case report.

Ossifying fibromas of the long bones of the leg are benign lesions occurring in the pediatric age group identical in histological appearance to the similarly named tumor of the jaw in adults. Most frequently presentation occurs after minor trauma with symptoms of a swelling of the tibia or fibula which may be painful. Pathological fracture or limp are also occasional presentations. Congenital cases are extremely rare. We describe an otherwise normal male neonate who presented at birth with a bowed right lower leg. The limb was 1 cm shorter than the other side, with tibia vara and a firm mass situated anteriorly. X-ray showed a mixed lytic and sclerotic lesion in the proximal metaphysis of the tibia. Biopsy showed collagenous stroma containing spindle cells and irregular trabeculae of woven bone rimmed by plump osteoblasts. As the appearances were typical of an ossifying fibroma (osteofibrous dysplasia) no surgical treatment was given. The patient was well with no growth of the tumor and with radiological evidence of healing at 1 year follow up. This case is presented to draw attention to the clinicopathological features of this unusual lesion which must be considered in the differential diagnosis of congenital lesions of the tibia.

Bone Neoplasms↗
PubMed1991

Heterogeneity in lymphokine profiles of CD4+ and CD8+ T cells and clones activated in vivo and in vitro.

Analysis of lymphokine mRNA expression and protein secretion by about 100 short-term alloreactive T-cell clones revealed marked heterogeneity in the combinations of lymphokines synthesized. This finding argues against a simple model in which T cells express either an unrestricted (Th0) or a restricted (Th1 or Th2) lymphokine profile. Lymphokine titers appeared to be normally distributed, with the percentage of positive clones for any one product determined by the threshold of detection. Accordingly, the observation that CD4+ clones on average produced higher titers of most lymphokines than CD8+ clones indicated that apparent differences between the lymphokine profiles of these two subsets were quantitative rather than qualitative. Patterns of lymphokine gene expression detected in whole tissues or by analysis of single cells and clones were markedly influenced by in vivo priming. Relative levels of expression of IL-4, IFN-gamma and GM-CSF in lymphoid tissues differed in mice undergoing a GvHR or following contact sensitization with OX or immunization with KLH in adjuvant. Consistent with the finding that IL-4 was the major lymphokine mRNA detected in lymph nodes of KLH-primed mice, most short-term KLH-specific clones derived from such mice also expressed IL-4. A similar approach to the detection of lymphokine-secreting T-cell precursors activated late in L. major infection showed that most clones from the L. major-resistant strain, C57BL/6, secreted IFN-gamma without IL-4 whereas most clones from the susceptible strain, BALB/c, secreted IL-4 without IFN-gamma. Differences were also noted in anti-CD3-induced IL-3 production at the single-cell level between CD8+ cells activated in the GvHR or against a tumor allograft. Con A-induced, filler cell-dependent cloning of CD4+ T cells from unprimed mice gave rise both to IFN-gamma-producing and to IL-4-producing clones. A requirement for an undefined, filler cell-dependent signal for development of IL-4-secreting clones was suggested by the finding that clones of normal CD4+ and CD8+ T cells activated in an anti-CD3-induced, filler cell-free system exclusively produced IFN-gamma and IL-3 without detectable IL-4 or IL-6. With a view to developing a single-cell approach to the analysis of lymphokine profiles of in vivo-activated T cells, sensitive assays for IL-3 and other lymphokines were used to measure secreting cells activated in the GvHR or against a tumor allograft.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Macrophages in haemopoietic and other tissues of the developing mouse detected by the monoclonal antibody F4/80.

Macrophages are widely distributed in lymphohaemopoietic and other tissues of the normal and diseased adult, where they play an important role in host defence and repair. Although the development of haemopoiesis has been well studied in several species, the ontogeny of the mononuclear phagocyte system remains poorly understood. We have used a highly specific mAb, F4/80, to examine the distribution of mature macrophages in the developing mouse, with special reference to their presence in the haemopoietic microenvironment. Monocytes and macrophages were first seen in embryos on day 10 in the yolk sac and liver as well as in mesenchyme. In liver, spleen and bone marrow, there was expansion of this population associated with the initiation of haemopoiesis on days 11, 15 and 17, respectively. Macrophages in these sites formed part of the haemopoietic stroma and their extensively spread plasma membrane processes could be seen making intimate contacts with clusters of differentiating haemopoietic cells. F4/80+ cells were widely dispersed in undifferentiated mesenchymal tissue in organs such as lung, kidney and gut. Numbers of F4/80-labelled cells increased concomitantly with organ growth and local mitoses were evident, as well as actively phagocytic macrophages. Our studies establish that macrophages are among the earliest haemopoietic cells to be produced during development and that they are relatively abundant in fetal tissues in the absence of overt inflammatory stimuli. Their distribution is correlated with the sequential migration of haemopoiesis and they constitute a prominent component of the stroma in fetal liver, spleen red pulp and bone marrow. Apart from a role in haemopoietic cellular interactions, their highly developed endocytic and biosynthetic activities suggest that macrophages contribute major undefined functions during growth, turnover and modelling of fetal tissues.

Animals↗
PubMed1991

Expression of a divalent cation-dependent erythroblast adhesion receptor by stromal macrophages from murine bone marrow.

Stromal macrophages in haemopoietic organs express novel surface receptors that are implicated in trophic interactions with developing blood cells. Macrophages isolated from foetal liver bind erythroblasts (Eb) by a divalent cation-dependent receptor (EbR), whereas stromal macrophages in adult bone marrow and lymphoid organs express a lectin-like receptor, sialoadhesin, which interacts with sialylated structures on sheep erythrocytes and murine haemopoietic cells. In order to learn more about the regulation of these haemagglutinins, we examined binding of Eb by stromal macrophages that had been isolated from adult murine tissues or generated in Dexter-type cultures of bone marrow. Macrophages were purified from bone marrow by collagenase digestion, adherence to a substratum and detachment of clustered haemopoietic cells, and tested for their ability to bind Eb from foetal liver or anaemic adult spleen. Freshly isolated bone marrow macrophages bound Eb mainly by a divalent cation-dependent activity that was not inhibited by neuraminidase treatment of Eb or by specific anti-sialoadhesin monoclonal antibodies, although these macrophages express sialoadhesin and Eb bear a potential ligand for this receptor. Macrophages obtained by digestion from other adult lymphoid tissues also bound Eb by a divalent cation-dependent activity, whereas blood monocytes and lavaged peritoneal macrophages failed to do so. Peritoneal macrophages could be induced to express high levels of sialoadhesin by cultivation in homologous mouse serum, but such macrophages did not acquire sialoadhesin-independent EbR activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Survey of reproductive health in young adults, greater Santiago, 1988.

This article reports the results of an interview survey with 1,665 residents of Metropolitan Santiago 15-24 years old. The survey, which dealt with various aspects of reproductive health, indicated that the sex education received by 75% of the subjects generally failed to convey an accurate knowledge of the basic concepts of sexuality; that use of contraceptive methods was very limited; that approximately 25% of the 865 women interviewed had been pregnant at some time; and that 40% of all the pregnancies were unplanned. These findings demonstrate a need to begin effective sex education programs and to provide adolescent services commensurate with the circumstances of modern life.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Adhesion receptors involved in the erythroblastic island.

We have defined two receptors involved in the binding of erythroblasts and other developing hematopoietic cells to murine macrophages. With 14-day-old fetal liver macrophages, which exclusively interact with erythroid cells in vivo, a divalent cation-dependent adhesion receptor, EbR, is able to mediate reversible attachment of erythroblasts in vitro. With adult resident bone marrow macrophages, which naturally bind a mixture of myeloid and erythroid cells, two distinct receptors are involved. Most of the binding is mediated by an EbR-like divalent cation-dependent receptor. The remainder is mediated by a divalent cation-independent receptor, SER, which was originally discovered by its ability to bind unopsonized sheep erythrocytes. To date, the molecular nature of EbR is unknown, but the failure of certain antisera and specific inhibitors to block its activity indicates that EbR may be a novel macrophage adhesion receptor. SER has recently been characterized by means of a monoclonal antibody selected on the basis of its ability to block binding of sheep erythrocytes. SER is a 185-K plasma membrane glycoprotein expressed specifically by resident bone marrow macrophages. Inhibition experiments have demonstrated that SER is able to mediate binding of erythroid and myeloid cells via recognition of sialylated glycoconjugates. The possible functions of EbR and SER in macrophage-hematopoietic cell interactions are discussed.

Animals↗
PubMed1991

Clinical management of the cardiovascular complications of the Marfan syndrome.

The Marfan syndrome is an autosomal dominant disorder of connective tissue with manifestations throughout the body. Diagnosis is based on the cardinal effects on the skeletal, ocular, and cardiovascular systems. Long limbs and digits, thoracic cage deformity, dislocation of the ocular lens, mitral valve prolapse, and dilatation of the aortic root are typical signs. Before recent advances in management, valvular regurgitation and aortic dissection accounted for over 90 percent of deaths, often in the third through fifth decades of life. Echocardiography, introduced nearly 2 decades ago, and the recent enhancements of cardiovascular Doppler techniques have greatly improved the ability of identifying patients with Marfan syndrome and following their clinical courses. Cardiovascular surgery has progressed over the same period to provide Marfan patients relatively safe approaches to repair of the life-threatening complications, and surgery should be offered prophylactically. The ability to intervene effectively in the Marfan syndrome requires a clear understanding of its natural history throughout life. This review discusses the clinical course and current management of the cardiovascular complications of the Marfan syndrome in children, young adults, and women considering pregnancy. These approaches have relevance to valvular and aortic problems found in the general population.

Aortic Aneurysm↗