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Biomedical subjects

D M Williams

Publications and source records attributed to D M Williams.

At least 325 records · Page 18Linked to original sources
PubMed1982

Malignant lymphoma occurring in a family.

Three patients, a 57-year-old man, his 60-year-old sister, and 81-year-old mother, developed non-Hodgkin's lymphoma within an interval of 12 months. There were histologic similarities of the biopsy material from these patients, but the clinical response was variable. Two patients achieved a sustained remission, and one expired after similar chemotherapy. Studies revealed slightly decreased numbers of circulating T lymphocytes in both surviving patients, and decreased cellular reactivity to mitogens in the man. HLA typing was not conclusive; HLA haplotypes were not the same as those reported in other families with non-Hodgkin's lymphoma. Electron microscopy of biopsy material revealed no viral inclusions. Except for the familial relationship, no common etiologic factors were identified.

Aged↗
PubMed1982

The role of antibody in host defense against the agent of mouse pneumonitis.

Athymic nude (nu/nu) mice, which are more susceptible to the agent of mouse pneumonitis (MoPn) (murine Chlamydia trachomatis) than are their heterozygous littermates (nu/+), do not develop significant IgG or IgA antibody to the MoPn agent. Nu/+ mice develop significant titers of both specific IgG or IgA antibodies after either intranasal or intrauterine challenge. Prior intranasal or intrauterine immunization protects nu/+ but not nu/nu mice against subsequent intranasal challenge with the MoPn agent. Resistance to pneumonia due to the MoPn agent can be transferred to nu/nu mice by nu/+ mouse immune serum (with high titers of IgG and IgA antibodies to the MoPn agent) but not by nu/+ mouse normal serum (with undetectable titers of IgG and IgA antibodies to the MoPn agent). Serum components, probably specific antibodies, are important in host defense against the MoPn agent.

Animals↗
PubMed1982

Treatment of murine cryptococcosis with liposome-associated amphotericin B.

Liposomes were prepared to incorporate large amounts of amphotericin B. BALB/c mice were challenged with Cryptococcus neoformans and given liposome-associated amphotericin B (AMBL) or amphotericin B-deoxycholate (AMBD) intravenously. Mice that were treated with AMBL survived longer and had lower tissue counts of cryptococci than mice treated with AMBD or untreated control mice. The reduced acute toxicity of AMBL permitted much larger doses of amphotericin B to be given than were possible with AMBD. AMBL is a novel vehicle of administration that reduces toxicity and concentrates the drug in the appropriate target organs.

Amphotericin B↗
PubMed1982

Effects of copper deficiency on the activity of the selenoenzyme glutathione peroxidase and on excretion and tissue retention of 75SeO3(2-).

Liver and lung activities of the antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined in control and copper-deficient rats. Decreased activity of SOD was found in liver and decreased activity of the selenoenzyme GSH-Px was found in liver and lung in the copper-deficient animals. The decreased liver activity of GSH-Px could be partially corrected by daily supplementation of the basal diet with sodium selenite. Urinary, fecal and biliary excretion of 75SeO3(2-) were determined in controls and copper-deficient rats in order to assess selenium losses. Urinary excretion of 75Se was not different in the two groups. Fecal loss of 75Se was increased in the copper-deficient animals when compared to controls and biliary excretion was decreased. Tissue retention of 75Se was also determined in both groups. Retention of 75Se in the copper-deficient rats was increased in brain and lung and decreased in liver. This pattern of tissue retention of 75Se is similar to that which occurs in selenium-deficient rats. Copper deficiency in rats results in decreased liver activity of both the copper-containing enzyme SOD and the selenoenzyme GSH-Px. The mechanism of decreased GSH-Px activity is unknown.

Animals↗
PubMed1982

Ossification in the caudal attachments of the ligamentum flavum. An anatomic and computed tomographic study.

A review of anatomic specimens and routine computed tomographic (CT) scans of the chest and abdomen demonstrated that ossification in the caudal attachments of the ligamentum flavum is a common anatomic finding, but a much less common CT finding. Its characteristic location should help prevent confusion with other entities. The present study was prompted by a case of thoracic spine trauma, reported here, in which areas of bone density in the spinal canal simulated fracture fragments. The true nature of these bony projections, namely ossification in the ligamentum flavum, was established by computer reconstruction of axial CT images.

Adult↗
PubMed1982

Amphotericin B in liposomes: a novel therapy for histoplasmosis.

Incorporation of amphotericin B into liposomes significantly altered its toxicity, tissue distribution, and efficacy. Compared with intravenously administered amphotericin B-desoxycholate, liposome-amphotericin B showed a reduced acute toxicity and a maximal tolerable dose 9 times greater than amphotericin B-desoxycholate. Liposome-amphotericin B also produced higher tissue and lower serum concentrations than amphotericin B-desoxycholate, and was significantly more effective in prolonging survival of mice infected with Histoplasma capsulatum.

Amphotericin B↗
PubMed1982

An ultrastructural and enzyme cytochemical study of the response of the neutrophil series to a local inflammatory stimulus in the rat.

Changes in neutrophil precursor populations in the bone marrow and their alkaline phosphatase reactivity following an inflammatory stimulus were studied in the rat using an osmiophilic method. Seven groups each of 3 Sprague-Dawley rats received subcutaneous injections of turpentine, and femoral marrow was examined at intervals up to 72 hr. Depletion of mature neutrophils resulted in an increased first in the myeloblast-promyelocyte compartment and at 48-72 hr in the myelocyte-metamyelocyte population. By 72 hr replenishment of the mature neutrophil marrow population had begun. Within 6 hr marked acceleration of cytoplasmic maturation was evident, together with accelerated synthetic activity, manifested by marked dilatation of the rough endoplasmic reticulum and an enlarged Golgi. Together with these changes there was an increase in the number of alkaline phosphatase reactive cells, which was evident first in the myeloblast-promyelocyte population at 2 hr. An absolute increase in the amount of enzyme reaction product associated with individual cells was also seen.

Alkaline Phosphatase↗
PubMed1982

DSH abstract: coverage of the world communicative disorders literature.

The percentage of journal articles covered by dsh Abstracts and the time it took these articles to appear as abstracts in this secondary publication were analyzed. Articles were obtained from nineteen communicative disorders journals every other year for the years from 1968 to 1976. Then the author index of dsh Abstracts was searched each year for up to five years following journal publication to determine whether each article was included in this abstracting service's coverage of the world literature. Of the 5548 articles included in the study, 3270 (59%) were covered by this abstracting service within a mean time of 9 months; however, time lag and coverage varied considerably for individual journals on a year by year basis. It was concluded that for historical searches and current awareness needs this secondary publication may not be meeting the information needs of communicative disorders specialists.

Abstracting and Indexing↗
PubMed1982

The effect of accelerated release of rat neutrophil polymorphonuclear leucocytes from bone marrow on cell accumulation in inflammatory exudates.

The purpose of this study was to establish whether there was enhancement or impairment of the migratory abilities of polymorphonuclear leucocytes (PMN) released prematurely into the circulation during the inflammatory response, as a consequence of their shortened bone-marrow transit time. Sixteen healthy young adult male Sprague-Dawley rats received an i.v. injection of 1 microCi (methyl-3H) thymidine per g body wt, followed 40 h later by the i.p. injection of 2 ml of a mixture of Brain Heart Infusion/Proteose Peptone (BHI/PP). Four, 8 and 12 h after injection of BHI/PP, isotope incorporation in blood and peritoneal exudates was compared by liquid scintillation counting. During the first 12 h of the inflammatory response there was no significant difference between levels of isotope incorporation in blood and peritoneal exudates. Thus the accelerated release of cells from the bone marrow did not affect their ability to emigrate into the local lesions during this period.

Animals↗
PubMed1981

Anterior salivary gland inclusion in the mandible: pathological entity or anatomical variant?

A case of anterior salivary gland inclusion of the mandible is reported and the literature reviewed. It is suggested that these inclusions arise in the same way as the more common examples from the angle of the mandible, by progressive resorption of the lingual cortex in response to pressure exerted by the adjacent salivary glands. It is likely that these lesions become evident on radiographs only when the resorption is marked, and they may, therefore, be more widespread than reported figures indicate. Supportive evidence for this hypothesis is provided by the observations that the lesions usually present in middle age and, on histological examination, exhibit evidence of resorption.

Bone Resorption↗
PubMed1981

Expression of Escherichia coli trp genes and the mouse dihydrofolate reductase gene cloned in Bacillus subtilis.

The mouse dihydrofolate reductase gene and a segment of the Escherichia coli trp operon are expressed in Bacillus subtilis when cloned in the "expression plasmid" pPL608. The cloned mouse gene confers trimethoprim resistance on B. subtilis and the cloned trp fragment complements mutations in the B subtilis trpD, C and F genes Expression of both cloned fragments is dependent on a promoter present in the vector plasmid. The E. coli trp fragment is cloned in a HindIII site within a chloramphenicol acetyltransferase gene present on pPL608, and as a result, expression of the E. coli trpC gene product is inducible by chloramphenicol. The mouse gene is inserted at a PstI site preceding the chloramphenicol acetyltransferase gene and its expression is not chloramphenicol inducible. The replication functions and neomycin-resistance of pPL608 are derived from pUB110. Accordingly, pPL608 is stably maintained at high copy number in B. subtilis.

Animals↗
PubMed1981

Biological responses of the bovine teat to milking: information from measurements of milk flow-rate within single pulsation cycles.

The mass flow-rate (FR) of milk from the bovine teat within individual pulsation cycles was measured by continuous computation of the average optical density of the milk-air mixture within a teatcup. Measurements during milking were made on both live and excised teats using a range of teatcup liners, vacuum levels and pulsation characteristics. During a typical pulsation cycle, soon after the start of milking, milk FR from live teats reached a peak within 100 ms of the start of the flow period and fell to about 60% of the maximum value between 0.5 and 1.5 s of flow. If the liner was held open for longer than 1.5 s, the FR typically declined a further 10% over the next 10-15 s. After 10-15 s little or no further change occurred in milk FR at normal milking vacuum levels. Milk flow from excised teats reached a steady value within 100 ms of the start of the flow period and showed no subsequent fall in FR. Within individual pulsation cycles the changes in FR from live teats are affected by: (i) the degree of compressive load applied by the collapsed liner to the teat in the preceding cycle; and (ii) the duration of application of the compressive load. Increasing the degree of compressive load or the length of time of loading increases the peak milk FR of the next cycle by reducing the degree of congestion in the tissues of the teat surrounding the teat canal. Muscular effects are of secondary importance. The relatively small changes in milk FR associated with muscle contractions of the teat can bae seen most clearly at low milking vacuum levels (below about 30 kPa) or with an unsupported teat (e.ag. using a very distensible, thin-walled liner).

Animals↗
PubMed1981

Racial differences of hemoglobin concentration: measurements of iron, copper, and zinc.

Nutritional surveys have demonstrated that Hb levels in blacks are consistently lower than in whites. This difference does not appear to be related to socioeconomic dietary differences, or differences of hereditary disorders such as sickle cell disease. We studied 47 black and 63 white subjects drawn from hospital employees. Mean Hb of black men was 0.9 g/dl less than that of white men. Mean Hb of black women was 0.5 g/dl less than that of white women. This difference was not associated with differences of serum iron, iron binding capacity, or transferrin saturation. Ferritin values of white women were significantly less than values observed in white men, but similar differences were not observed between black men and women. The explanation for this is unclear although may be related to sample size or differences of menstrual status. Copper levels were lower in white men than in any other group, and zinc levels were essentially similar between racial groups. The red blood cells of blacks were also smaller than those of whites. This difference could not be explained by disordered Hb synthesis. These observations confirm that Hb concentrations in both black men and women are lower than in their white counterparts. This difference cannot be explained by differences in iron, copper, or zinc nutriture. Further, measurements of Hb in nutritional survey populations reflect iron status as only one of several variables and should not be used as the only assessment of iron nutrition.

Adult↗
PubMed1981

Pneumonia due to Chlamydia trachomatis in the immunocompromised (nude) mouse.

Athymic nude mice (nu/nu) were significantly more susceptible to pneumonia due to the agent of mouse pneumonitis (MoPn), Chlamydia trachomatis, than their heterozygous (nu/+) littermates, as judged both by a greater mortality and a decreased ability to rid their lungs of the infection. Nu/nu mice did not produce significant antibody to the MoPn agent, whereas nu/+ mice did. Thymic transplantation rendered nu/nu mice significantly more resistant to the MoPn agent than nu/nu controls. Resistance to the MoPn agent and production of specific antibody to the MoPn agent were dependent on thymus-derived cells.

Animals↗
PubMed1981

Immunologic studies of disseminated infection with Aspergillus fumigatus in the nude mouse.

Immunity to infection with Aspergillus fumigatus conidia was studied in the athymic nude (nu/nu) mouse. The intratracheal, intravenous, and intraperitoneal routes of infection were used. Nu/nu mice were not significantly more susceptible than their heterozygous (nu/+) littermates. However, only nu/+ animals could be protected by prior immunization and developed positive, A. fumigatus-specific skin tests. Protection could be transferred to nu/nu recipients by immune glass-adherent cells. Thus, immunity to invasive aspergillus infection is multifactorial and depends on a glass-adherent cell population and T-cells.

Animals↗