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Biomedical subjects

M R Smith

Publications and source records attributed to M R Smith.

At least 235 records · Page 13Linked to original sources
PubMed1977

The snare method of laparoscopic sterilization: an analysis of 1,000 cases with 4 failures.

The snare method has proven to be an effective method of tubal resection for sterilization. In the most experienced hands, significant complications are indeed rare. However, the failure rate appears to be higher than that of the coagulation-alone method, at least in the postabortal patient. The necessity for pathologic confirmation, a tradition of surgery, is critically questioned. Additional coagulation of the tubal ends after resection is now recommended, especially in the patient seeking abortion as well as sterilization. The authors await the comparative long-term results of bipolar forceps and the newer mechanical methods of laparoscopic tubal sterilization. It is conceivable that the snare and other unipolar electrosurgical instruments designed for female sterilization will become obsolete.

Adolescent↗
PubMed1976

Salpingitis: a frequent response to intrauterine contraception.

Nonbacterial, chronic salpingitis was found in less than 1% of non-IUD users undergoing elective tubal sterilization, Nonbacterial, chronic salpingitis was found in 47% of IUD users undergoing elective sterilization. Speculation about the influence of this finding on inflammatory morbidity is presented.

Adult↗
PubMed1975

A radioimmunoassay for the estimation of serum dehydroepiandrosterone sulphate in normal and pathological sera.

A radioimmunoassay is described for the measurement of dehydroepiandrosterone sulphate in serum. The method requires 0.1 ml of serum that needs no purification other than a single ether extraction. It is both rapid and economical, procedural losses are small and precision and accuracy are acceptable for both normal and pathological sera. Normal values have been established for children and adults which show a relationship to chronological age, values rising steadily as puberty intevenes, peak values occurring between 20 and 27 years, with a decline thereafter. An empirical curve was fitted to the data and approximate normal limits were obtained. The mean value for pregnanat women in the age range 20-40 years, was statistically significantly lower than in non-pregnant, premenopausal women. The levels of dehydroepiandrosterone sulphate in cord and newborn blood, were higher than at any other time during childhood until signs of puberty were demonstrable. Elevated levels are reported in six patients with untreated congenital adrenal hyperplasia and in one patient with a tumour of the adrenal cortex. It is suggested that this assay provides a useful and precise index of adrenal androgen secretion.

Adolescent↗
PubMed1975

Nonobstructive hypertrophic cardiomyopathy mimicking mitral stenosis. Documentation by echocardiography, phonocardiography and intracardiac pressure and sound recordings.

The physical findings in hypertrophic cardiomyopathy with left ventricular outflow tract obstruction are well described. In the absence of outflow tract obstruction the findings are less distinctive. There have been several reported cases in which the cardiac findings have suggested the diagnosis of mitral stenosis, In this report we describe a patient whose auscultatory and roentgenographic findings more closely mimicked mitral stenosis. The patient had a loud first heart sound, mitral opening snap and an apical presystolic murmur; left atrial enlargement was present. Noninvasive studies, including phonocardiography, echocardiography and apex cardiography, strongly suggested the correct diagnosis of nonobstructive hypertrophic cardiomyopathy. The diagnosis and unusual auscultatory findings were confirmed by results of cardiac catheterization and intracardiac phonocardiography. The importance of recognizing this syndrome and the use of noninvasive methods to establish the diagnosis are stressed.

Angiocardiography↗
PubMed1975

Polypeptide nature of growth requirement in yeast extract for Thermoplasma acidophilum.

The active component(s) in yeast extract required by Thermoplasma acidophilum for growth is polypeptide in nature. A fraction from yeast extract was isolated and partially characterized as one or more peptides of molecular weight about 1,000 containing 8 to 10 amino acids. Although it was composed largely of basic and dicarboxylic amino acids, only one amino group per molecule was free. The polypeptide(s) appeared to bind avidly to cations. No other organic compounds except glucose were needed by Thermoplasma. Among several hundred known compounds tested, only glutathione plus Fe2+ or Fe3+, clostridial ferredoxin, and spinach ferredoxin elicited any growth response.

Amino Acids↗
PubMed1975

The role of C3 as an opsonin in the early stages of infection.

In order to investigate the role of C3 in host defense in vivo, normal AKR/J mice, genetically deficient in C5, were depleted of serum C3 by the injection of purified cobra venom factor (CoVF). Concurrent with their C3 depletion, their serum opsonizing activity decreased to a level less than 20% of normal. When these mice were challenged with an intraperitoneal injection of pneumococci 2 hr after the CoVF treatment, the LD50 was from 30 to 80 times lower than the LD50 in saline-treated control animals. When the CoVF was given only 6 hr after the pneumococcal challenge, the LD50 was the same as in the control mice. If the pneumococci were first preopsonized in vitro and then injected into CoVF-treated animals, the LD50 was the same as that in control animals. These experiments demonstrate that C3 plays a significant role in vivo in the host's defense against infection and that a major part of that role is through its action as an opsonin. Furthermore, these experiments demonstrate that the role of C3 is most significant during the early stages of bacterial invasion.

Animals↗
PubMed1975

Antibody-mediated suppression of grafted lymphoma. III. Evaluation of the role of thymic function, non-thymus-derived lymphocytes, macrophages, platelets, and polymorphonuclear leukocytes in syngeneic and allogeneic hosts.

Syngeneic or allogeneic mice pretreated with sublethal whole-body irradiation were rendered incapable of suppressing the growth of grafted tumor cells sensitized with alloantibody. The growth of sensitized tumor cells was suppressed when they were mixed with donor effector cells from mice syngeneic or allogeneic to the recipients and then were inoculated in irradiated recipients. Three donor-host combinations were used to study the suppression of the murine lymphoma 6C3HED indigenous to C3H mice. These were C3H donor cells in C3H recipients, C57BL/6 donor cells in C3H recipients, or C57BL/6 donor cells in C57BL/6 recipients. In all three combinations, macrophages obtained from an inflammatory exudate, exudate lymphocytes not bearing theta antigen, and platelets were, in descending order of effectiveness, consistently active in restoring antibody-mediated suppression of tumor growth in irradiated hosts. Prior irradiation of the transferred lymphocytes somewhat diminished their effectiveness. Freeze-thawed or heat-killed macrophages (but not freeze-thawed platelets or lymphocytes) were effective in restoration. Peripheral blood mononuclear leukocytes and splenic lymphoid cells were not active in the recipients syngeneic to the donor cells but were acitve in recipients allogeneic to the donor cells. Polymorphonuclear leukocytes isolated from peripheral blood or an inflammatory exudate were not active. Intact thymic function seems unimportant since antibody-mediated suppression took place as effectively in thymectomized mice as in normal controls.

Animals↗
PubMed1975

Heat labile opsonin system to pneumococcus.

Normal mammalian sera contain the heat labile opsonin system that promotes the phagocytosis of various microorganisms by polymorphonuclear leukocytes. Because the heat labile opsonin system is present in normal nonimmune sera and because it operates against various microorganisms in an apparently nonspecif manner, it is considered to play an important role during the early phase of an acute bacterial infection. The role of various factors participating in the heat labile opsonin system, and its in vivo significance are discussed.

Animals↗
PubMed1974

Isolation of an acidic surface antigen from a conventional strain of Staphylococcus aureus.

Staphylococcus aureus strain 7007, a prototype isolated from a hospital burn unit, was shown to exhibit a significant degree of resistance to ingestion by mouse polymorphonuclear leukocytes. An acidic surface antigen was isolated from strain 7007 by a combination of 10% trichloroacetic acid extraction, ion-exchange chromatography, and gel filtration. Chemical analysis indicated that the surface antigen consists of an unknown aminouronic acid and an amino sugar. Immunochemical analysis suggested that the 7007 antigen is a common feature of all the strains collected from the burn unit. No cross-reactivity was observed between the carbohydrate preparations of various hospital staphylococcal strains and the 7007 heteropolymer. These results suggested the possibility that the surface antigen of strain 7007 represents a strain- or type-specific antigen.

Agglutination Tests↗
PubMed1972

Serological typing of Staphylococcus epidermidis strains by the serum-soft agar technique.

Antisera to five different diffuse forms of Staphylococcus epidermidis were prepared in rabbits as a mean of serological differentiation of S. epidermidis strains. These antisera converted the growth types of the homologous strains from diffuse to compact form in serum-soft agar but did not convert the heterologous strains. The converting activities of the antisera were absorbed out with homologous organisms and not by heterologous strains, indicating the specific serological properties of these strains. Further, the converting activity was absorbable with cell surface substance extracted by sonic oscillation and was not absorbed with cells from which this surface substance had been removed. With these factor sera and the serum-soft agar technique, S. epidermidis strains were differentiated, and it was found that 102 of 116 strains or 87.9% were typable. Within the 102 typable strains, 49 and 53 typed as monovalent and polyvalent, respectively. No correlation between source and strain types of S. epidermidis was found.

Adsorption↗
PubMed1972

Platelets in early hyperacute allograft rejection in kidneys and their modification by sulfinpyrazone (Anturan) therapy. An experimental study.

Experiments were carried out on mongrel dogs to study the early ultrastructural changes in hyperacute rejection of kidney. Renal allografts were performed on dogs presensitized by three to five skin grafts. The animals were grouped in pairs, control and treated with sulfinpyrazone, a platelet inhibitor. The electron microscopic studies showed that the earliest change in the kidney was aggregation of platelets mainly in the peritubular capillaries and a few glomeruli. Later, platelets showed degranulation with vascular damage leading to rejection of kidney. Treated dogs showed less tendency for platelets to aggregate, and graft survival was prolonged. The role or platelets in the hyperacute rejection is discussed.

Animals↗