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Biomedical subjects

D Drake

Publications and source records attributed to D Drake.

At least 37 records · Page 2Linked to original sources
PubMed1997

Staged pull-through for rectosigmoid Hirschsprung's disease is not safer than primary pull-through.

Conventional treatment of Hirschsprung's disease consists of initial colostomy followed by pull-through (staged PT). During the past decade immediate definitive operation (primary PT) has been reported by several investigators with a complication rate ranging from 0% to 20%. In the authors' institution primary PT has been performed since 1992 in patients with rectosigmoid aganglionosis responsive to rectal irrigations. The authors reviewed the records of all patients (n = 124) with Hirschsprung's disease diagnosed and treated between 1989 and 1995. One hundred sixteen patients underwent a definitive operation. This study analysed the complications observed in 87 of these patients with aganglionosis limited to the rectosigmoid colon. Patients were divided into groups according to the type of surgical treatment (staged versus primary), the year of operation (1989 through 1992 versus 1992 through 1995), and the age at primary PT (15 infants age < or = 4 months versus 10 children age > 4 months). There were no deaths. There was no significant difference in complication rates between staged PT and primary PT. Similar complication rates were encountered in infants and children who underwent primary PT. The rate of postoperative complications did not change according to the year of the operation. Major complications were observed in all 3 patients who had a primary Swenson PT compared with 20% who had a primary Duhamel PT. Staged Swenson and Duhamel PT had similar complication rates. The authors conclude that (1) staged PT for rectosigmoid Hirschsprung's disease is not any safer than primary PT; (2) primary PT can be performed safely in young infants; and (3) primary Swenson PT is less satisfactory than primary Duhamel PT.

Child↗
PubMed1997

Meconium ileus: a ten-year review of thirty-six patients.

Of 36 neonates with meconium ileus secondary to cystic fibrosis treated over a 10-year period, twenty-one (58%) had simple uncomplicated disease while fifteen (42%) had complications which included perforation (5), volvulus (6) and atresia (5). Gastrografin enema was employed in 20 infants with relief of obstruction in 8 (40%). Operative procedures consisted of resection and primary anastomosis in seventeen patients, stomas were fashioned in six, three had an enterotomy with irrigation only and two had Bishop-Koop enterostomy. Post-operative complications developed in 5 (18%) of these 28 patients. The overall survival rate was 97%. The one death occurred in an infant with short bowel syndrome, patent ductus arteriosus, hydrocephalus and pulmonary damage. There were eight additional patients who had meconium obstruction in the absence of cystic fibrosis.

Cystic Fibrosis↗
PubMed1997

Controlling substance abuse. A narcotic audit tool.

A medical center formed a narcotic task force because of widespread concern over misuse of drugs. Systems and staff issues were addressed. Audits to help identify and alleviate the problem were conducted; two narcotic audit tools are shown.

Humans↗
PubMed1997

Antibacterial activity of baking soda.

The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque.

Anti-Bacterial Agents↗
PubMed1997

Effect of enamel microabrasion on bacterial colonization.

PURPOSE: To determine if microabraded surfaces inhibit Streptococcus mutans colonization. MATERIALS AND METHODS: Ten extracted molars were obtained and sectioned in half mesio-distally. The mesial side was treated with microabrasion (PREMA Compound). The distal surface was designated as the control site. A plastic tube was secured on each surface with resin composite, exposing a surface of 13.2 mm 2. S. mutans 10,499 was cultured in TSB-YE supplemented with 5% sucrose and 2.5% glucose was added to each secured site in addition to 50 microliters of cell suspension. Samples were incubated in a 5% CO2 chamber for 7 days at 37 degrees C. Samples were taken from each site, incubated with dextranase (75 micrograms 1 ml), sonicated, and vortexed to disrupt cellular aggregates as much as possible. Samples were then plated on Mitis-Salivarius agar using a spiral plating system. Enumeration of numbers of colonizing bacteria was achieved following standard spiral plating system methodology. RESULTS: The mean for the microabraded group was 1.12 x 10(2) cfu/tooth and for the control it was 1.15 x 10(4). Analyzing the data revealed a significant difference (P = 0.0188).

Colony Count, Microbial↗
PubMed1996

Intestinal glycosaminoglycans in neonatal necrotizing enterocolitis.

Advanced necrotizing enterocolitis (NEC) is a common neonatal surgical emergency of unknown aetiology. Despite improvements in the prognosis, the aggressive form of the disease is still associated with significant rates of morbidity and mortality. Recent evidence indicates that the extracellular matrix (ECM) is important in gastrointestinal development and glycosaminoglycans, major constituents of the ECM, are attenuated in inflammatory bowel disease. The hypothesis of this study was that changes in the nature and distribution of intestinal glycosaminoglycans occur in NEC. The distribution and nature of glycosaminoglycans were determined in 31 sections of well preserved resection margins and severely diseased bowel from eight neonates affected by NEC. An established histological method of glycosaminoglycans analysis using cationic gold with silver enhancement was employed in this study. The identity of specific glycosaminoglycans was also elucidated using a combination of cationic gold staining and glycanase digestion. In well preserved tissue, staining was seen throughout the full thickness of the bowel. The epithelial basement membrane and basolateral surfaces, lamina propria and submucosa were particularly prominent. In moderate disease, patchy loss of anionic sites was frequently observed with glycosaminoglycans-deficient areas adjacent to intact sites. In severe NEC, there was extensive loss of glycosaminoglycans in most of the sections examined. Glycanase analysis revealed that the glycosaminoglycans in well preserved tissue were sensitive to chondroitinase ABC and only vascular sites were sensitive to heparinase III. The consequences of glycosaminoglycans loss in NEC as demonstrated in this study are not known but modulation of gastrointestinal glycosaminoglycans could be important in the pathogenesis of NEC and may underlie some of the clinical manifestations of this condition.

Colon↗
PubMed1996

Resection and primary anastomosis in necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is the most common surgical emergency in the newborn. Up to half of babies with NEC develop advanced disease requiring surgical intervention. Options include peritoneal drainage under local anaesthetic, enterostomy only, resection and enterostomies, and resection with primary anastomosis. Resection with enterostomies is favoured by many paediatric surgeons but management of neonatal enterostomies can be difficult. The outcome of 26 infants undergoing surgery for advanced NEC over a 2-year period is reviewed. Resection and primary anastomosis was possible in 18 infants of whom two (11%) died. Recurrent NEC developed in four (22%) and strictures in three (17%) of these infants. An initial enterostomy was fashioned in eight infants, three following resection of necrotic intestine and five as a proximal diverting stoma in infants with pan-intestinal involvement. Five of these eight infants died (63%), giving an overall mortality of 27%. Primary anastomosis is an effective procedure following resection of grossly involved intestine in infants with NEC. The mortality and morbidity in this series compared well with those reported for staged procedures.

Anastomosis, Surgical↗
PubMed1996

Antibacterial activity of baking soda.

The antibacterial activity of baking soda (sodium bicarbonate) was assessed using three different experimental approaches. Standard minimum inhibitory concentration analyses revealed substantial inhibitory activity against Streptococcus mutans that was not due to ionic strength or high osmolarity. Short-term exposure assays showed significant killing of bacterial suspensions when baking soda was combined with the detergent sodium dodecylsulfate. Multiple, brief exposures of sucrose-colonized S mutans to baking soda and sodium dodecylsulfate caused statistically significant decreases in numbers of viable cells. Use of oral health care products with high concentrations of baking soda could conceivably result in decreased levels of cariogenic S mutans in saliva and plaque.

Anti-Infective Agents, Local↗
PubMed1994

Interferon-alpha generation in mice responding to challenge with UV-inactivated herpes simplex virus.

In humans with advanced human immunodeficiency virus (HIV) infection, an interferon-alpha (IFN-alpha) response by a specialized blood mononuclear cell to herpes simplex virus (HSV) in vitro is associated with resistance to opportunistic infections. A cell type of unknown lineage, designated the natural IFN-producing cell (NIPC), has been identified preliminarily as the source of these IFNs and may have a role in other host defense functions. Earlier studies suggested the existence of analogous HSV-responsive cell populations in mice. The role specifically of IFN-alpha in the murine system, however, has not been characterized. Using IFN bioassay and neutralization with antisera against Type I IFNs and IFN-beta, we have defined the types and sources of IFNs produced by mice in response to in vivo and in vitro challenge with UV-inactivated HSV. After intraperitoneal inoculation with HSV, BALB/c and C57Bl/6 strains produced characteristically different levels of serum IFNs that appeared principally to be IFN-alpha. The response of mononuclear cells from these mice differed from that of the intact mouse. Isolated cells from bone marrow and spleen released detectable IFNs much later than did whole animals, and the IFNs produced by marrow, spleen, and peritoneal cells were usually neutralized by the anti-IFN-beta. Only bone marrow cells produced detectable amounts of IFN-alpha. Both intact mice and their cells became refractory to restimulation with similar kinetics.

Animals↗
PubMed1994

Growth-inhibitory effect of pyrophosphate on oral bacteria.

The purpose of this investigation was to determine whether pyrophosphate, the anticalculus component of tartar-control dentifrices, exerts antimicrobial activity against oral bacteria commonly found in supragingival plaque. Minimal inhibitory concentrations of pyrophosphate were determined for Streptococcus sanguis, Streptococcus mutans (serotype c), Actinomyces viscosus and Actinomyces naeslundii. All of the bacteria tested were susceptible to pyrophosphate with identical minimal inhibitory concentrations of 0.67% wt/vol (25 mM). Bactericidal kinetics assays revealed that both S. mutans and A. viscosus were killed by pyrophosphate, with the latter being considerably more susceptible. The mechanism of killing was not due to high ionic strength, as comparable controls showed no loss in numbers of viable cells. Brief exposure (two 5-min incubations) of S. mutans to pyrophosphate and sodium dodecyl sulfate caused pronounced inhibition of growth over the 24-h test period. Under the constraints of the conditions used, these studies indicate that pyrophosphate and sodium dodecyl sulfate can substantially inhibit the growth of oral bacteria. These compounds may affect the oral microflora of patients who routinely use tartar-control dentifrices and mouthrinses.

Actinomyces↗
PubMed1994

Enriched HLA-DQ3 phenotype and decreased class I major histocompatibility complex antigen expression in recurrent respiratory papillomatosis.

Respiratory papillomas, caused by human papillomaviruses, are benign tumors that recur following removal. We evaluated immune function and major histocompatibility complex (MHC) phenotype and expression in these patients. MHC-independent immune function appeared normal. The frequency of peripheral blood MHC class II phenotypes was highly enriched for DQ3 and DR11, one split of DR5. Class I MHC antigen expression on papilloma tissue was markedly reduced. Together, these phenomena may facilitate papillomavirus evasion of the cellular immune response.

Adult↗
PubMed1994

Differences in adhesion of Candida albicans 3153A cells exhibiting switch phenotypes to buccal epithelium and stratum corneum.

Cells of the laboratory strain 3153A of Candida albicans can be stimulated to undergo high-frequency phenotypic switching by a low dose of UV. We have compared the adhesive properties of cells exhibiting the basic original smooth (o-smooth) phenotype and three switch phenotypes (star, irregular wrinkle, and revertant smooth) to buccal epithelium and stratum corneum. The generalized hierarchy of adhesion is as follows: o-smooth > irregular wrinkle > revertant smooth > star. This is the inverse of the hierarchy of the proportions of elongate hyphae formed by these phenotypes in culture. These results suggest that the differences in adhesion between o-smooth and the three switch phenotypes of strain 3153A reflect, at least in part, the level of interference due to the formation of elongate hyphae, which tend to cause clumping in suspension. No major differences in the levels of adhesion of cells of the different phenotypes between buccal epithelium and stratum corneum were observed. Results which demonstrate that buccal epithelium induces germination (hypha formation) by conditioning the medium are also presented.

Adhesiveness↗
PubMed1994

Impaired interferon alpha response in hairy cell leukemia is corrected by therapy with 2-chloro-2'-deoxyadenosine: implications for susceptibility to opportunistic infections.

Patients with hairy cell leukemia (HCL) are susceptible to opportunistic intracellular infections, suggesting defects in cellular immunity. Prior studies have indicated an association between failure of IFN-alpha generation by peripheral blood mononuclear cells (MNC) and susceptibility to such infections. We here present results on IFN-alpha generation in HCL patients pre- and post-therapy. Prior to treatment with 2-chloro-2'-deoxyadenosine (CdA), MNC from 24 HCL patients with active disease produced little or not IFN-alpha (geometric mean < 40 IU/ml) compared with controls (n = 140, geometric mean 1730 IU/ml, p < 0.0005). After treatment with CdA, IFN-alpha generation was studied in 16 patients, with a geometric mean value of 650 IU/ml (p < 0.0005 compared with pre-CdA levels). The severe depression of IFN-alpha generation improved progressively following CdA therapy-induced clinical remission. We propose that deficiency of IFN-alpha production may play a role in the susceptibility to intracellular infections of patients with active HCL.

Adult↗
PubMed1993

The biologic activity of ACTH and related peptides on peripheral blood mononuclear cells is altered by the presence of dexamethasone.

We wished to determine whether the glucocorticoid hormone dexamethasone (dex), a potent modular of both pituitary-adrenal and immunologic activity, altered the effect of adrenocorticotropin-related peptides on activated peripheral blood mononuclear cells (PBMCs) and T-cells. PBMCs preactivated with Concanavalin A (Con A) and T-cells preactivated with phorbol 12,13 dibutyrate (PDB) plus phytohemagglutinin (PHA) were exposed to dex, ACTH, and related peptide sequences. Proliferation of cells was measured as was IL-2 in conditioned media. It was found that in the absence of dex only the peptide ACTH(18-39) altered proliferation of PBMCs while there was no effect of peptide on T-cells activated via protein kinase C-mediated pathways. Significant reversal of the inhibitory effect of dex on proliferation of PBMCs exposed to Con A was achieved with addition of ACTH(1-39) and ACTH(11-24), while IL-2 levels were unaffected by the addition of peptide. ACTH(18-39) and ACTH(11-24) enhanced the inhibitory effect of dex on T-cells activated with PDB plus PHA. These findings suggest that the biologic activity of ACTH on immune cells is altered when dexamethasone is present and under certain circumstances ACTH may protect the immunologic response from the inhibitory effects of elevated ambient glucocorticoids.

Adrenocorticotropic Hormone↗
PubMed1993

Acquisition of manganous ions by mutans group streptococci.

The cariogenic bacteria Streptococcus sobrinus and S. cricetus were shown to have an absolute requirement for manganous ion in order to bind glucans or to adhere to glass in the presence of sucrose. The bacteria possessed a reasonably high affinity transport system for 54Mn2+, yielding a Km of about 12 microM. The Vmax for uptake of 54Mn2+ in S. sobrinus was increased when the bacteria were grown in Mn-depleted medium, but the Km remained the same. There was no evidence for two Mn2+ uptake systems, commonly observed for many bacteria. Ions such as Ca2+, Co2+, Co3+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, Ni2+, and Zn2+ did not inhibit the uptake of 54Mn2+ by the bacteria, although Cd2+ was a potent inhibitor. Fractionation experiments showed that manganese was distributed in protoplasts (67%) and in the cell wall (33%). Approximately 80% of the 54Mn2+ in S. sobrinus was rapidly exchangeable with nonradioactive Mn2+. Electron spin resonance experiments showed that all of the manganese was bound or restricted in mobility. Proton motive force-dissipating agents increased the acquisition of 54Mn2+ by the streptococci, probably because the wall became more negatively charged when the cell could no longer produce protons.

Bacterial Adhesion↗