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Biomedical subjects

J Singer

Publications and source records attributed to J Singer.

At least 109 records · Page 6Linked to original sources
PubMed1980

Legionnaires' disease in Johannesburg.

Legionnaires' disease (LD) was first identified as an epidemic pneumonia occurring in the USA in 1976. Sporadic cases have since been identified in many countries. This report describes the first 2 cases in South Africa of LD with pneumonia in patients in whom the diagnosis was established by the finding in early acute and follow-up convalescent sera of a greater than fourfold rise in titre with the immunofluorescent antibody test. The microbiological investigations are discussed in some detail and the clinical, radiological and laboratory features of LD are briefly reviewed.

Complement Fixation Tests↗
PubMed1980

Physiologic timing of orthodontic treatment.

1. With the knowledge that certain facial bones respond in growth similarly to the growth of long bones, the hand-wrist film can be used as an indicator of the maturational status of the orthodontic patient. 2. Six stages of hand-wrist development have been advocated as guides in the timing of treatment with the stages geared to the individual patient rather than to statistical tables. 3. Stage 2 represented the important early prepubertal period when much growth was ignored but during which Class II correction could be effectively achieved without prolonged periods of mechanotherapy. 4. It was emphasized that the puberal growth spurt could be overlooked by the clinician. In addition, puberal spurt in the female may be of such a short duration that much growth may have already elapsed by the time this stage was recognized. 5. Stage 5 represented the period of residual growth during which posttreatment changes could occur. At the present state of the art these changes seem to be unpredictable but some warning may be possible with the use of the hand-wrist film taken prior to the termination of treatment. 6. The clinician is encouraged to utilize the hand-wrist film as another diagnostic aid. A few easily recognizable events can indicate the individual's maturational status.

Adolescent↗
PubMed1980

Different types of endotoxin-induced release of colony stimulating factors by adherent leucocytes in the presence of fresh and heat-inactivated autologous serum.

Human adherent leucocytes stimulate in vitro granulopoiesis by releasing colony stimulating factors (CSF), which promote the growth of myeloid committed stem cells (CFUC). The effect of lipopolysaccharide (LPS) on CSF generation by adherent leucocytes was studied with fresh and heat-inactivated autologous serum. Adherent leucocyte conditioned media were fractionated on Sephadex G-75. LPS, in the presence of fresh serum, caused a significant increase of CSF release by adherent leucocytes within 1 h. Heat inactivation of autologous serum abolished this effect. Adherent leucocyte CSF had 3 activity peaks at greater than 75 000, 23 000 and less than 4 000 daltons. LPS-fresh serum initiated CSF, harvested after culture periods of 1 and 24 h, disclosed identical elution profiles.

Cell Adhesion↗
PubMed1980

Marrow transplantation in thirty "untransfused" patients with severe aplastic anemia.

Thirty patients with severe aplastic anemia had no transfusions of blood products until just before marrow transplantation from HLA-identical family members. They were conditioned for grafting with cyclophosphamide, 50 mg/kg body weight on each of 4 successive days. All 30 had prompt initial marrow engraftment, which was sustained in 27. Twenty-five of the 30 are alive between 9 to 84 (median, 19.5) months. The actuarial projection of survival for 2 to 6 years is 75%. Twenty of the 25 surviving patients have no problems. Five have chronic graft-versus-host disease, resolving in two and active in three. Five patients died with infection or hemorrhage, four of whom had graft-versus-host disease. These data show that early transplantation should be carried out before transfusions are given for any patient with severe aplastic anemia who has an HLA-identical family member. If sensitization to minor transplantation antigens contained in blood products is avoided, the incidence of marrow-graft rejection will decrease, and survival will improve.

Adolescent↗
PubMed1979

Methylation of DNA in mouse early embryos, teratocarcinoma cells and adult tissues of mouse and rabbit.

The distribution and amount of 5-methylcytosine (5-MeCyt) in DNA was measured for early embryos of mouse strain CF1 (2 to 4 cell stage to blastocyst) and mouse teratocarcinoma cells. In each case, the pattern of methylation was examined by use of the restriction enzymes Hha I and HPA II HPA II, which cut DNA at the sites 5'GCGC and 5'CCGG respectively, when the cytosines at these sites are not methylated. Mouse embryo DNA was found to have the same level of methylation as adult mouse tissues, and no changes in methylation were seen during differentiation of the teratocarcinoma cells. The ratio of 5-MeCyt/Cyt in DNA was measured by high performance liquid chromatography for the differentiating teratocarcinoma cells and for several adult mouse and rabbit tissues. The variation between tissues or between teratocarcinoma cells at different stages of differentiation was less than 10 percent. These results are discussed in view of proposals that 5-MeCyt plays a role in differentiation.

Animals↗
PubMed1979

Methylation of mouse liver DNA studied by means of the restriction enzymes msp I and hpa II.

The restriction enzymes Hpa II and Msp I both recognize the sequence 5'-CCGG (C, cytosine; G, guanine). However, Hpa II cuts mouse liver DNA to fragments four times larger than does Msp I. The size of DNA cut by Msp I is close to that predicted from base composition and nearest neighbor analysis. The most probable explanation of these results is that in mouse the site 5'-CCGG is highly methylated.

Animals↗
PubMed1979

Antepartum determination of pre-ejection period of fetal cardiac cycle: its relation to newborn body weight.

Simultaneous recordings of the fetal electrocardiogram and ultrasound Doppler-cardiogram were used for the determination of the pre-ejection period (PEP) of the fetal cardiac cycles. All 50 fetuses selected for the present study experienced uneventful perinatal lives despite maternal antepartum complications which required hospitalization. A significant positive correlation between the PEP and gestational age of the fetuses was again demonstrated. The PEP of the fetus measured within one week prior to delivery was also found to be significantly correlated with the newborn body weights at birth. Statistical analysis demonstrates that fetal body weight was more closely related to the physiologic lengthening of the PEP.

Birth Weight↗
PubMed1979

Avoiding patient relation stress in an orthodontic practice.

1. Consumer rights apply to the practice of orthodontics as well as other areas of health care. 2. To avoid consumer complaints, the orthodontist must be prepared to deal with personality problems as well as treatment complications in his practice. 3. Only by careful questioning of the patient before treatment will the orthodontist be able to detect possible future problems. 4. An explanation of informed consent by the orthodontist and an acknowledgement of it in writing, signed by the parent or responsible party, is now regarded as essential to avoid misunderstandings and complaints. 5. An informed patient leads to a better relationship with the orthodontist as well as a healthier atmosphere in which to practice.

Communication↗
PubMed1979

Occult fractures in the production of gait disturbance in childhood.

Trauma to the lower extremities is the principal cause of gait disturbance in early childhood. Three cases are presented to emphasize the relative frequency of children hospitalized for diagnostic evaluation of altered gait who have occult fractures. The cases may refresh the primary physician of the variables that serve as obstacles to accurate diagnosis.

Child↗
PubMed1979

Postvaricella suppurative meningitis. Case reports and review of the literature.

Suppurative meningitis should be recognized as being a complication of varicella. The clinician must assiduously exclude suppurative meningitis that at times may be clinically indistinguishable from the typical postinfectious encephalomyelitis of varicella. Misdiagnosis of the cause of CNS alterations during the course of varicella is possible.

Chickenpox↗
PubMed1978

Chronic lymphocytic leukaemia: Clonal origin in a committed B-lymphocyte progenitor.

The glucose-6-phosphate dehydrogenase (G.-6-P.D.) types of isolated blood-cell populations and normal skin were determined in two patients with chronic lymphocytic leukaemia (C.L.L.) who were heterozygous at the G.-6-P.D. locus. Normal tissues from each patient manifested both A and B G.-6-P.D. types, but the C.L.L. B-lymphocyte preparation from one patient showed only a single enzyme type, and from the other patient it showed 95% activity of one G.-6-P.D. type. These observations confirm the supposition based on immunoglobulin-marker data that at the time of study C.L.L. has a clonal origin. In contrast to the B lymphocytes, granulocytes, erythrocytes, platelets, and T lymphocytes displayed both enzyme types in proportions similar to those found in skin. These findings indicate that C.L.L. involves committed B-lymphocyte progenitors. Thus, the disease stands in contrast to chronic myelocytic leukaemia and other myeloproliferative syndromes, all of which involve multipotent haemopoietic stem cells.

Aged↗
PubMed1978

Ectopic secretion of chorionic gonadotropin by a lung carcinoma. Pituitary gonadotropin and subunit secretion and prolonged chemotherapeutic remission.

The ability of tumor markers to improve cancer therapy is not established. We studied a man with a human chorionic gonadotropin (HCG)-secreting large cell carcinoma of the lung and gynecomastia. Preoperatively, levels of HCG (109 ng/ml), its alpha and beta subunits (3.2 and 21 ng/ml, respectively) and plasma estradiol were elevated. Despite apparently complete tumor resection and total resolution of gynecomastia, HCG titers remained elevated (3.3 ng/ml), heralding tumor recurrence three weeks later. Because the pathophysiologic consequences of the ectopic secretion of HCG on pituitary function are not established, we administered 100 microgram of gonadotropin-releasing hormone (LHRH) and observed a markedly delayed increase in pituitary gonadotropins. Early chemotherapy, guided by persistence of HCG, reduced HCG to undetectable levels, restored to normal the response to LHRH and resulted in a distinctly unusual 30-month complete remission. Use of HCG as a tumor marker levels is more sensitive than the symptom of gynecomastia and may permit detection of small, potentially curable tumor foci.

Carcinoma, Small Cell↗