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Biomedical subjects

J B Hall

Publications and source records attributed to J B Hall.

At least 91 records · Page 5Linked to original sources
PubMed1989

Acute or chronic respiratory failure. Assessment and management of patients with COPD in the emergency setting.

Patients with acute or chronic respiratory failure exhibit severe pulmonary impairment as a baseline characteristic. Additional minor insults can precipitate cardiopulmonary failure that requires hospital admission and possibly mechanical ventilation. Our approach to these patients emphasizes evaluation of the imbalance between neuromuscular competence and mechanical load on the respiratory system. In this way, reversible factors can be identified and corrected before they progress to inspiratory muscle fatigue and respiratory failure. For cases in which deterioration is inexorable, guidelines for mechanical ventilation are given and approaches to eventual liberation from the ventilator are reviewed.

Arrhythmias, Cardiac↗
PubMed1989

Increased hydrogen peroxide in the expired breath of patients with acute hypoxemic respiratory failure.

Acute hypoxemic respiratory failure (AHRF) can result from diverse lung insults. Toxic oxygen metabolites have been implicated in this clinical condition and in animal models of pulmonary edema. Hydrogen peroxide (H2O2), an oxygen metabolite, mediates tissue injury. We measured H2O2 levels by a spectrophotometric technique in the breath condensate of 68 mechanically ventilated patients; 13 patients with normal lungs undergoing elective surgery had no such detectable levels of H2O2. Fifty-five patients in the ICU meeting criteria for the adult respiratory distress syndrome (ARDS) had a higher concentration of H2O2 in the expired breath condensate than ICU patients without pulmonary infiltrates (2.34 +/- 1.15 vs 0.99 +/- 0.72 mumol/L, p less than 0.005). This marker had a sensitivity of 87.5 percent and a specificity of 81.3 percent in separating the two patient populations. Patients with AHRF and focal pulmonary infiltrates who did not meet criteria for ARDS also had higher concentrations of H2O2 (2.45 +/- 1.55 mumol/L) than patients without pulmonary infiltrates (p less than 0.001). No difference was observed between the expired H2O2 concentrations of patients with ARDS or patients with focal pulmonary infiltrates. Patients with brain injury or sepsis tended to have higher levels of H2O2 regardless of lung pathology. Increased levels of H2O2 are detected in the expired breath of ICU patients with focal lung infiltrates and in ARDS patients, which is consistent with the hypothesis that oxygen metabolites participate in the pathogenesis of ARDS and other forms of AHRF.

Breath Tests↗
PubMed1989

Effects of recombinant DNA-derived somatotropin and dietary energy intake on development of beef heifers: I. Growth and puberty.

The effects of dietary energy intake and somatotropin (STH) on growth and puberty were studied in 40 Angus heifers. At an average age of 7 mo (208 +/- 8 d), heifers were assigned to four treatment groups: 1) vehicle (V) + high energy (HE; 2.68 Mcal ME/kg DM), 2) recombinant DNA-derived STH (20.6 mg/d; s.c.) + HE, 3) V + low energy (LE; 2.22 Mcal ME/kg DM) or 4) STH + LE. Animals remained on treatments until 15.5 mo of age. Body weights (BW), hip heights (HH) and areas of pelvic openings (PA) were measured every 28 d and backfat thicknesses (BF) were measured every 56 d. Plasma progesterone was measured in blood samples taken three times per week beginning at 9 mo of age to determine age at first ovulation. Heifers fed HE were heavier (P less than .01), gained faster (P less than .01) and had greater BF (P less than .01) than those fed LE. Animals treated with STH gained faster (P less than .01) and were heavier (P less than .05) between 12 and 15 mo of age than V-treated heifers. Heifers treated with STH also had less BF (P less than .05) and a tendency for a greater (P = .08) increase in HH than in V-treated heifers. Somatotropin interacted with energy (P less than .05) and age (P less than .01) to influence PA. Somatotropin increased (P less than .01) PA in heifers fed the HE diet but not in those fed the LE diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1989

Effects of recombinant DNA-derived somatotropin and dietary energy intake on development of beef heifers: II. Concentrations of hormones and metabolites in blood sera.

The effects of somatotropin (STH) and energy intake on serum concentrations of glucose (GLU), insulin (INS), nonesterified fatty acids (NEFA), urea nitrogen (UN) and insulin-like growth factor-I (IGF-I) were determined in 40 Angus heifers. At 7 mo (208 +/- 8 d) of age heifers were assigned to four treatment groups: 1) vehicle (V) + high energy (HE; 2.68 Mcal ME/kg DM), 2) recombinant DNA-derived STH (20.6 mg/d; s.c.) + HE, 3) V + low energy (LE; 2.22 Mcal ME/kg DM) or 4) STH + LE. Animals remained on treatments until an average of 15.5 mo of age. Blood samples were taken every 30 min for 4 h at 9, 11, 13 and 15 mo of age to determine circulating concentrations of metabolites and hormones. Serum IGF-I was increased (P less than .01) by STH injections, but this effect appeared to diminish with age (STH x age; P less than .01). Energy intake did not influence IGF-I levels. Somatotropin increased (P less than .01) serum GLU in heifers fed the HE diet but only tended (P = .08) to increase GLU in those fed the LE diet (STH x energy; P = .05). Although STH increased (P less than .01) serum INS in both energy groups, the response in heifers fed the HE diet was greater (P less than .02) than that in heifers fed the LE diet (STH x energy; P less than .05). Heifers fed LE had higher (P less than .01) concentrations of NEFA than heifers fed HE.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1989

The expression of Lewis antigens in neoplasms of the gastrointestinal tract.

The indirect immunoperoxidase technique has been used to demonstrate Lea and Leb antigens in paraffin sections of both morphologically normal gastric and colonic mucosae and their neoplastic counterparts. Expression differed in various regions of the gastrointestinal tract: Leb occurred most frequently in the stomach and Lea most frequently in the colon. Coexpression of Lea and Leb occurred in only 5% of cases of normal mucosa, in 65% of gastric carcinomas and in 82% of carcinomas of the colon. Furthermore, 75% of cases of intestinal metaplasia in gastric mucosa and 30% of tubular adenomas, 50% of villous adenomas and 70% of tubulovillous adenomas in the colon co-expressed Lea and Leb antigens. In this study, the expression of Lewis antigens in carcinoma was found to differ from that of adjacent normal mucosa in 95% of cases of gastric carcinoma and 100% of cases of colonic carcinoma. The differences were shown by antigen acquisition and/or deletion. Similar changes were shown in 88% of cases of intestinal metaplasia in gastric mucosa, 20% of cases of tubular adenomas and 57% of cases of villous and tubulovillous adenomas of colon.

Adenoma↗
PubMed1987

Liberation of the patient from mechanical ventilation.

Discontinuation of mechanical ventilation is too frequently difficult and frustrating for the patient and the clinician alike. With the view that expeditious withdrawal of mechanical support is often a mirror-image exercise requiring reversal of the factors that led to respiratory failure, we begin with a discussion of the various pathophysiologies of respiratory failure. We then describe an approach emphasizing assessment of respiratory load and neuromuscular function at the bedside, with strategies outlined for diminishing mechanical load while conditioning and strengthening respiratory muscles to the point that spontaneous ventilation can be sustained.

Humans↗
PubMed1987

A simulation model for the analysis of Space Station gas-phase trace contaminants.

A simulation model for the analysis of gas-phase trace contaminants in the cabin air of the NASA Space Station Reference Configuration was developed at the NASA Langley Research Center. The model predicts changes in trace contaminant concentrations from both physical and chemical sources an sinks as a function of time. Simulations were performed in which values for relative humidity, temperature radiation intensity, pressure, and initial species concentrations were constrained to values for the parameters measured and modeled in the continental tropics at the Earth's surface. Species concentrations simulated using the model compared favorable with concentrations in the continental tropics which demonstrated that the chemical mechanism in the trace contaminant model approximates changes atmospheric species concentrations. The sensitivity of initial species concentrations to producing change in additional species concentrations was also assessed. Results from the model indicated that chemical reactions will be important in determining the composition of cabin air in the Space Station. It is anticipated that the trace contaminant model will be useful in assessing the impact of experiments a commercial operations on the composition of the cabin air in the Space Station.

Air Pollutants↗
PubMed1986

Pseudoobstruction of the colon.

A previously unreported complication of extraperitoneal node dissection, pseudoobstruction of the colon, is described as a case report, and its etiology and treatment are discussed.

Adult↗
PubMed1986

An approach to mediastinal masses associated with hyperthyroidism.

Benign thymic hyperplasia (BTH) is a known feature of hyperthyroidism, but is infrequently appreciated by clinicians. In most cases thymic enlargement is minimal; however, it may occasionally present as an appreciable anterior mediastinal mass. While surgical resection is a common approach to such a mass, recognition of the benign nature of BTH and its regression following treatment of hyperthyroidism would prevent a major surgical procedure. We present three cases of BTH associated with hyperthyroidism and describe our approach to this syndrome.

Adolescent↗
PubMed1986

Successful spontaneous vaginal delivery during mechanical ventilatory support for the adult respiratory distress syndrome.

The adult respiratory distress syndrome is a common cause of acute hypoxemic respiratory failure in the adult that is associated with a high mortality. There is a limited experience with managing this entity in the gravid patient. A case of successful management of mother and fetus through spontaneous delivery is presented, followed by a discussion of the principles of supportive therapy.

Adult↗
PubMed1985

Evaluation of the cerviscope as a screening instrument.

The cerviscope has been proposed as a screening tool for use in conjunction with the Papanicolaou smear as a system offering many of the same advantages as colposcopy and cytology. One hundred twenty-five patients were evaluated with the cerviscope who had been referred to this colposcopy clinic with a diagnosis of dysplasia. The purpose of this study was to evaluate the instrument's potential as a screening adjunct in the context of simultaneous evaluation by colposcopy. Thirty-nine percent (49 patients) were unevaluable due to technical problems (defective cervicogram, nonvisualized squamocolumnar junction). Significantly, 67% (26 patients) of the 39 patients reported as having negative cervicograms had a biopsy-proven dysplasia (19 mild, 4 moderate, 3 severe). By the chi 2 method, this is statistically significant (P less than 0.001).

Adult↗
PubMed1985

Effect of nutrition on the LH response to calf removal and GnRH.

Ten primiparous crossbred cows were assigned to two dietary groups at calving. One group received 120% and the other group received 80% of the National Research Council (NRC) recommended allowance of dietary energy for primiparous cows. At 60 days postpartum, calves were removed from their dams. Blood samples were collected from the cows at 15-min intervals for 8 hr beginning at the time of calf removal and again 24 hr, 48 hr and 72 hr after calf removal. At 72 hr after calf removal, all cows were given 200 ug GnRH intravenously. At calf removal, serum LH concentrations were higher (P<0.01) for cows on 120% (0.9 +/- 0.03 ng/ml) compared to cows on 80% (0.5 +/- 0.03 ng/ml) of recommendations. Serum LH concentrations increased (1.6 +/- 0.1 ng/ml, P<0.01) by 24 hr in cows on the highenergy diet. In contrast, a similar increase was not observed in cows on the low-energy diet until 48 hr after calf removal (1.4 +/- 0.2 ng/ml, P<0.01). These contrasting patterns in serum LH concentrations resulted in a diet by time interaction (P<0.01). Serum LH concentrations increased in both dietary energy groups following GnRH injection, but the response was greater (P<0.01) in cows on the low-energy diet compared to the cows fed the high-energy diet. These results indicate that inadequate dietary energy delays the LH response to calf removal and increases the LH response to exogenous GnRH.

Journal Article↗
PubMed1985

Control of hypertension with nifedipine in the setting of aortic dissection.

We report a 61-year-old man with dissection of the descending aorta and hypertension in whom medical management with beta-blocking antihypertensives was precluded by a history of asthma. The calcium channel blocker nifedipine was successfully employed in this setting and the rationale for its use is discussed.

Aortic Dissection↗
PubMed1984

The prognostic significance of adenomyosis in endometrial carcinoma.

Depth of myometrial invasion is accepted as one of the most important prognostic factors in carcinoma of the endometrium. In an effort to define the significance of adenomyosis containing adenocarcinoma as it relates to myometrial invasion, 52 cases of Stage I adenocarcinoma with coexisting adenomyosis were identified. A subset of 11 cases was noted to have adenocarcinoma in adenomyosis, invasive to a depth greater than would have been appreciated had this entity not been identified. These 11 cases had a 100% 5-year survival, suggesting that adenocarcinoma in adenomyosis does not indicate a more ominous prognosis. The depth of invasion into the myometrium proper is the significant prognostic factor. The pathologist must be able to differentiate these two distinct entities to accurately assess prognosis.

Adenocarcinoma↗
PubMed1984

Vasculitis and glomerulonephritis: a subgroup with an antineutrophil cytoplasmic antibody.

Four subjects whose plasma produced positive staining of neutrophil cytoplasm, on testing for antinuclear factor, have been found over eight years (and over 10,000 antinuclear factor studies). All four had evidence of diffuse systemic disease with polyarthralgia and lung involvement. Three of four (at least) had evidence of renal involvement and two of four skin biopsy evidence of vasculitis. Defining such a subgroup may help in defining etiology(s) and treatment regimes in diffuse vasculitic disease.

Antibodies, Antinuclear↗
PubMed1983

Antimicrobial action of compound 48/80--II mechanism of action.

The mixture of compounds called compound 48/80 had been shown to have antimicrobial activity against a wide variety of microorganisms. In this paper it is shown that its primary site of attack appears to be on the membrane of the cell. In its presence, Tetrahymena became much more sensitive to osmotic stress, and alpha-methylglucose was rapidly released from preloaded Escherichia coli cells. The drug also had effects on cell viability, respiration, cell division, and the release of material absorbing at 260 nm. In general, its effects paralleled those of polymyxin B, although its structure is quite different except for the presence of amino groups and hydrophobic regions in both molecules. The activity of 48/80 was not due to detergent-like, surface-active properties and was antagonized by magnesium and other cations and by phosphatidylserine. Purification of the active principle might provide a relatively simple and readily modifiable probe of membrane function and possibly a new family of useful antimicrobial compounds.

Animals↗