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M Agarwal

Publications and source records attributed to M Agarwal.

At least 109 records · Page 6Linked to original sources
PubMed1989

Molecular epidemiology of adhesin and hemolysin virulence factors among uropathogenic Escherichia coli.

The pap, prs, pil, and hly operons of the pyelonephritic Escherichia coli isolate J96 code for the expression of P, F, and type 1 adhesins and the production of hemolysin, respectively; the afaI operon of the pyelonephritic E. coli KS52 encodes an X adhesin. Using different segments of these operons as probes, colony hybridizations were performed on 97 E. coli urinary tract and 40 fecal clinical isolates to determine (i) the presence in the infecting bacteria of nucleotide sequences related to virulence operons, and (ii) the phenotypic properties associated with such sequences. Coexpression of P and F adhesins encoded by pap-related sequences was detected more frequently among isolates from patients with pyelonephritis (32 of 49, 65%) than among those with cystitis (11 of 48, 23%; P less than 0.0001) or from fecal specimens (6 of 40, 15%; P less than 0.0001). Therefore, the expression of both adhesins appears to be critical in the colonization of the upper urinary tract. In contrast, afaI-related sequences were detected significantly more frequently among isolates from patients with cystitis, suggesting that this class of X adhesin may have a role in lower urinary tract infections. Urinary tract isolates differed from fecal isolates by a low incidence of type 1 adhesin expression among pil probe-positive isolates. hly-related sequences were only detected in pap probe-positive isolates. The frequency of hemolysin production among pap probe-positive isolates was not associated with a particular pattern of infection. The distribution of these virulence factors was similar in the presence or absence of reflux, indicating that structural abnormalities of the urinary tract did not facilitate colonization by adhesin-negative isolates.

Adhesins, Escherichia coli↗
PubMed1989

Mucus transport in a miniaturized simulated cough machine: effect of constriction and serous layer simulant.

The transport of mucus gel simulant (MGS) in a constricted simulated cough machine, using blood plasma as a serous layer simulant (SLS), was investigated. MGS was prepared from locust bean gum solutions crosslinked with varying amounts of added borate to produce gels of varying spinnability (filance). The model trachea was a plexiglass channel of rectangular cross-section with the plane bottom surface. The upper surface included a sinusoidal protrusion which provided a flow convergence with minimum gaps of 6, 4 and 2 mm. Experiments for mucus transport were conducted for these minimum gaps, as well as for the non-convergent case (12 mm gap). Miniaturization of sample quantity was achieved by keeping the MGS layer depth constant (0.5 or 1 mm) but reducing the zone of loading from 13.4 cm to 1 cm, thus reducing the sample requirement to as little as 0.2 ml. MGS transport was determined as the minimum displacement of a line of marker dye placed in the MGS layer at the point of minimum constriction gap. It was shown that in all cases (dry as well as with SLS), MGS transport increased as the minimum constriction gap between the plane and the convergent top surface decreased. This increase was further enhanced if an SLS of lesser viscosity was used. It was also found that the transport of MGS increased as the depth of MGS layer increased or as the filance decreased in both non-constricted and constricted cases. The relationship between MGS transport and filance was maintained even in the presence of an SLS layer.

Airway Obstruction↗
PubMed1988

Further evidence supporting a cause and effect relationship between blood transfusion and earlier cancer recurrence.

Studies of associations between perioperative blood transfusions and later recurrence of solid tumors have yielded conflicting results. A previous analysis of transfused patients suggested that recurrence was associated with transfusion of whole blood as opposed to red blood cell concentrates. Additional analyses were performed on patients with cancers of the colon, rectum, cervix, and prostate to determine if patients receiving whole blood, red blood cells only, or no transfusions had differing outcomes. Patients receiving 1 unit or more of whole blood had uniformly poor outcomes compared with nontransfused patients (p less than 0.001). In contrast, patients receiving only red blood cells had progressively worse recurrence and death rates with increasing numbers of transfusion, suggesting the presence of a dose-effect relationship. Employing multivariate techniques, blood transfusion of less than or equal to 3 units that included any whole blood were independently and significantly associated with earlier recurrence (p = 0.003) and death due to cancer (p = 0.02). Transfusions of less than or equal to 3 units of blood comprised solely of red blood cell concentrates were associated with no greater risk of recurrence than that seen in patients receiving no transfusion (p = 0.50). These results provide a potential explanation for the disparate results reported in studies of blood transfusion and cancer outcome. The marked difference in outcome seen between patients receiving a few units of red blood cells and comparable patients receiving even one unit of whole blood are consistent with the hypothesis that transfusion of stored blood plasma causes earlier tumor recurrence in some instances. Strategies for reducing these risks might include avoidance of whole blood transfusions when only 1-3 units are required, more conservative transfusion practice, use of autologous blood transfusions, and perhaps, use of red blood cells washed free of plasma and white cell debris. Clinical trials to test these hypotheses are urgently needed.

Colonic Neoplasms↗
PubMed1982

Brain metastases in breast cancer patients receiving adjuvant chemotherapy.

A retrospective analysis was performed comparing the incidence of brain metastases as a site of first recurrence in patients receiving adjuvant chemotherapy during the period from 1973--1979 for node-positive operable carcinoma of the breast, compared to a matched control group of patients presenting during the same period treated by local measures only. Five of 115 patients (4.3%) receiving adjuvant chemotherapy have had brain metastases as first site of distant recurrence compared to zero of 115 (0%) in the control group. This comprised 12.8% of first distant recurrences in the adjuvant group. The authors suggest that this increased incidence of brain metastases, as site of first recurrence, reflects prolonged suppression of systemic disease by adjuvant chemotherapy with less effect in controlling metastases in the brain.

Adult↗