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Biomedical subjects

M J Patterson

Publications and source records attributed to M J Patterson.

At least 37 records · Page 2Linked to original sources
PubMed1995

Thermal tolerance following artificially induced polycythaemia.

Polycythaemia has been shown to improve physical performance, possibly due to increased arterial oxygen transport. Enhanced thermoregulatory function may also accompany this manipulation, since a greater proportion of the cardiac output becomes available for heat dissipation. We further examined this possibility in five trained men, who participated in three-phase heat stress trials (20 min rest, 20 min cycling at 30% peak power (Wpeak) and 20 min at 45% Wpeak at 38.3 (SEM 0.7) degrees C [relative humidity 41.4 (SEM 2.9)%]. Trials were performed during normocythaemia (control) and polycythaemia, obtained by reinfusion of autologous red blood cells and resulting in significant elevation of arterial oxygen transport. During the polycythaemic trials, the subjects demonstrated diminished thermal strain, as evidenced by a significant reduction in cardiac frequency (fc: 12 beats.min-1 lower throughout the test; P < 0.05), and reduced auditory canal temperatures (Tac) during the latter 20-min phase (P < 0.05). Forearm sweat onset was more rapid (363.0 compared to 1083.0 s; P < 0.05), and forearm sweat rate (msw) sensitivity was elevated from 1.80 to 2.91.mg.cm-2.min-1.degrees C-1 (P < 0.05). Forehead msw was depressed during the final 20 min, while forearm msw was greater during all test phases, averaging 0.94 and 1.20 mg.cm-2.min-1, respectively, over the 60 min. Skin blood flows for the upper back, upper arm and forearm were reduced (P < 0.05). Polycythaemia enhanced thermoregulation, through an elevation in forearm sweat sensitivity and msw, but not via increased cutaneous blood flow. These modifications occurred simultaneously with decreases in fc and Tac, resulting in greater thermal tolerance.

Adult↗
PubMed1994

Screening maternal serum alpha-fetoprotein levels and human parvovirus antibodies.

The association between gestational infection with human parvovirus (B19) and fetal loss has increased interest in this virus and demand for diagnostic testing. However, serological assays for B19 are not yet widely available. Maternal serum alpha-fetoprotein (MSAFP) testing is commonly used during the second trimester to screen for various fetal defects. We attempted to determine whether an elevated level of MSAFP would be an appropriate indication for B19-specific tests. Over a 26-month period, MSAFP tests were performed at Michigan State University for 21 392 women. Sera remaining after that testing were stored frozen. Of these, 22 cases samples--from women with MSAFP levels greater than 3.0 multiples of the median (MOM) and pregnancies that ended in fetal loss--and 44 matched control samples--from women with MSAFP levels greater than 0.4 and less than 2.2 MOM and live births at term--were tested for B19 antibodies. None of the 66 samples was IgM positive, while 33 (50 per cent) were IgG positive. The presence of IgG was not significantly associated with case or control status (matched odds ratio = 0.77, 95 per cent confidence interval 0.28-2.11). These findings are consistent with other studies indicating prior infection in approximately half of adults and suggest that elevated screening MSAFP levels, in the absence of other evidence of B19 infection, should not prompt B19-specific testing.

Adult↗
PubMed1994

Attenuation of the cutaneous blood flow response during combined exercise and heat stress.

Skin blood flow (SkBF) was measured in six male subjects using laser-Doppler velocimetry, with zero-gradient auditory canal temperature (Tac) used as an index of body core temperature (Tc). Subjects performed incremental, upright cycling commencing at 40% peak power (Wpeak: 10 min), increasing every 4 min by 5% Wpeak thereafter. Trials were conducted in hot (ambient temperature (Ta) 36.7 +/- 0.2 degree C, relative humidity (rh) 46.1 +/- 3.2%; mean +/- S.D.), and neutral environments (Ta 19.6 +/- 0.3 degree C, rh 50.2 +/- 1.4%). SkBF increased with Tac in all subjects. Attenuation of SkBF occurred at the same Tac, relative SkBF and cardiac frequency (fc) between environments, but at a lower exercise intensity (40.8 +/- 0.8% versus 55.8 +/- 3.0% Wpeak) in the hot environment (p < 0.05). Data indicate that Tc thresholds for SkBF attenuation may exist. However, it is suggested that attenuation thresholds coincided with a reduced central blood volume, which may occur at a critical level of cutaneous blood pooling.

Adult↗
PubMed1993

Treatment of systemic candidiasis in a neutropenic murine model using immunoglobulin G bearing liposomal amphotericin B.

Efficacy of immunoglobulin G (IgG) bearing liposomal amphotericin B (LAMB-IgG), liposomal amphotericin B without IgG (LAMB) or free amphotericin B (fAMB/Fungizone) was investigated in the treatment of systemic candidiasis in a neutropenic mouse model. Treatment with a single dose (0.6 or 0.9 mg amphotericin B per kg body weight) of LAMB-IgG resulted in a significant increase in the survival rate of neutropenic mice infected with 3 x 10(5) cfu of Candida albicans compared to untreated controls, mice injected with IgG, or liposome alone. Survival was also better in neutropenic mice treated with LAMB-IgG than in neutropenic mice treated with the same dose of LAMB or fAMB. Moreover, 65% of all mice survived the infection after treatment with a single dose of 0.6 mg AMB of the LAMB-IgG formulation. Quantitative culture counts of organs showed that both fAMB and LAMB-IgG formulations even at a dose of 0.3 mg AMB/kg, cleared C. albicans from the spleens, livers, and lungs but not from the kidneys. However, a decreased number of C. albicans cells was recovered from the kidneys of mice that survived the infection. Results of the study suggest that LAMB-IgG is more effective than LAMB or fAMB in the therapy of disseminated candidiasis in neutropenic mice.

Amphotericin B↗
PubMed1991

Evaluation of antibody-bearing liposomal amphotericin B in the treatment of systemic candidiasis in a neutropenic murine model.

The efficacy of liposomal amphotericin B bearing anticandidal antibodies (LAMB-Ab) was investigated in the treatment of systemic candidiasis in a murine model made neutropenic by an intraperitoneal injection of cyclophosphamide. Treatment with a single dose (0.6 mg amphotericin B kg-1 body weight) of LAMB-Ab resulted in an improved survival of neutropenic mice infected with Candida albicans compared to neutropenic mice treated with identical doses of liposomal amphotericin B or free amphotericin B.

Amphotericin B↗
PubMed1987

Esophageal carcinoma with prominent spindle cells.

Eight cases of esophageal carcinoma with prominent spindle cells (carcinosarcoma or pseudosarcoma) were studied using the avidin-biotin immunoperoxidase method and monoclonal antibodies to various keratins and vimentin. In all eight cases positive immunoreactivity for keratin was found in carcinomatous areas and for vimentin, in the spindle cells. It is interesting that five cases demonstrated focal immunoreactivity to keratin in the spindle cell component. Trace positivity to vimentin was seen in the carcinomatous areas in one case. These findings are consistent with the hypothesis that esophageal carcinoma with prominent spindle cells is of epithelial origin and may represent a morphologic variant of squamous cell carcinoma.

Aged↗
PubMed1985

Epithelioid leiomyosarcoma originating in a hamartomatous polyp from a patient with Peutz-Jeghers syndrome.

A case of Peutz-Jeghers syndrome with long history and multiple resections is presented. Despite the large number of intestinal polyps in these patients, malignant transformations are rare. In this case, an epithelioid leiomyosarcoma developed within a single polyp. At the time of resection this tumor had already metastasized to the liver. The histology and ultrastructure of this tumor is presented. Reviews of the clinical syndrome and leiomyosarcoma are given, with discussion of the possible interaction of these two processes as presented in this patient.

Adult↗
PubMed1982

Antibody to hepatitis A and hemodialysis.

Antibody to hepatitis A virus (anti-HAV) was surveyed in 469 patients from 20 of 31 Michigan hemodialysis units, during spring 1978. The mean point prevalence of anti-HAV was 59.5% and within the 20 individual units ranged from zero to 100%. For the entire survey population, the point prevalence of anti-HAV was significantly greater with increasing age, among blacks, and in individuals with hypertension as their underlying renal disease. Anti-HAV was independent of sex, duration of dialysis, or the presence of either hepatitis B surface antigen or its associated antibody. Within individual units, anti-HAV prevalence was associated with a higher mean patient age but not with dialysis unit size, mean duration of dialysis therapy, race, or prevalence of hepatitis B markers among patients or staff. These data support reports that transmission of the hepatitis A virus is neither associated with hemodialysis therapy nor routinely spread by parenteral mechanisms as observed in hepatitis B virus transmission.

Adolescent↗
PubMed1979

Prevalence of hepatitis B in 27 Michigan hemodialysis centers.

A large epidemiological survey of inhospital chronic hemodialysis patients was conducted in 27 (93%) of the 29 dialysis centers in Michigan. Serum was collected from 699 patients on chronic maintenance hemodialysis for periods from one month to eight years. Hepatitis B surface antigen (HBsAg) was determined in all patients by radioimmunoassay and positive samples were confirmed by specific neutralization. Antibody against HBsAg (anti-HBs) was determined by radioimmunoassay in 110 HBsAg negative patients from six dialysis units with a high prevalence of hepatitis B. HBsAg was detected in 80 (11.4%) patients distributed among 21 (78%) of 27 dialysis units and anti-HBs in 34 (31%) patients from the selected dialysis units. The prevalence of HBsAg was related to duration of dialysis, number of blood transfusions, and to a history of bilateral nephrectomy, but not to age, sex, race, nor the underlying renal disease. Twenty-one (26%) of the 80 HBsAg positive patients had not been previously identified by the clinical laboratories of their institutions. Since preventive measures were not taken in the care of these inapparent carriers of HBsAg, they represent an unrecognized risk.

Blood Transfusion↗
PubMed1978

Hepatitis B surface antigen in urine of hemodialysis patients.

As part of an extensive epidemiological survey of chronic hemodialysis patients in Michigan, hepatitis B surface antigen (HBsAg) was identified in the sera of 79 of 701 (11%) patients. Of these patients, 59 were carriers of HBsAg for three or more months. Urine samples were collected from 36 of 39 HBsAg carriers having urinary output. Of these samples, 19 (52%) were positive for HBsAg by radioimmunoassay; this was confirmed by specific antibody neutralization. The HBsAg was not identified in the urine of seven hemodialysis patients who were lacking serum HBsAg or in urine samples from three HBsAg sero-carriers who had normal renal function. Patients undergoing maintenance hemodialysis appear to constitute a large reservoir of HBsAg chronic carriers. This study indicates that a minimum of 50% of persistent HBsAg carriers who are producing urine have detectable HBsAg in single, randomly timed, unconcentrated urine specimen. These data suggest that urine may represent a potential vehicle for transmission in nonparenterally acquired hepatitis B.

Hepatitis B Surface Antigens↗