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Biomedical subjects

S E Morris

Publications and source records attributed to S E Morris.

At least 37 records · Page 2Linked to original sources
PubMed1996

Necrotizing group A streptococcal infections associated with streptococcal toxic shock syndrome.

BACKGROUND: Group A streptococci (GAS) cause a variety of life-threatening infectious complications, including necrotizing fasciitis (NF), purpura fulminans (PF), and streptococcal toxic shock syndrome (strepTSS), in which bacteremia is associated with shock and organ failure. METHODS: We reviewed our experience in the management of patients with necrotizing GAS infections from 1991 to 1995. RESULTS: Eight adult patients (6 NF, 2 PF) were identified. Patients presented with fever, leukocytosis, and severe pain, and rapidly developed shock and organ dysfunction. The diagnosis of strepTSS was confirmed in 6 cases. A total of 54 surgical procedures were required, including widespread debridements and amputations. Two patients died (25%). CONCLUSIONS: Recognition of the need for aggressive diagnosis and surgical treatment of this most rapidly progressive surgical infection is necessary for successful management.

Adult↗
PubMed1995

Second-order analysis of space-time clustering.

We consider the problem of detecting and describing space-time interaction in point process data. We extend existing second-order methods for purely spatial point process data to the spatial-temporal setting. This extension allows us to estimate space-time interaction as a function of spatial and temporal separation, and provides a useful reinterpretation of a popular test, due to Knox, for space-time interaction. Applications to simulated and real data indicate the method's potential.

Cluster Analysis↗
PubMed1993

Etiology and consequences of respiratory failure in thermally injured patients.

Inhalation injury predisposes burn patients to pneumonia, respiratory failure, and death, but the incidence and consequences of respiratory failure in the absence of inhalation injury are not well known. In a review of 529 burn patients admitted over a 4-year period, patients with inhalation injury had a 73% incidence of respiratory failure (hypoxemia, multiple pulmonary infections, or prolonged ventilator support) and a 20% incidence of adult respiratory distress syndrome (ARDS). In patients without inhalation injury, respiratory failure developed in 5% of patients and ARDS in 2% (both p < 0.001). Patients with respiratory failure display a high incidence of multiple organ failure and mortality (27% to 50%), regardless of the presence of inhalation injury. All patients who died had multiple organ failure. This review demonstrates that respiratory failure, regardless of its cause, frequently leads to multiple organ failure and death. Inhalation injury, in the absence of respiratory failure, does not appear to contribute to mortality.

Adult↗
PubMed1993

Aminoglycoside dosing in burn patients using first-dose pharmacokinetics.

Burn patients have altered aminoglycoside pharmacokinetics, which often result in subtherapeutic serum concentrations when these drugs are administered by conventional dosing (CD) methods. First-dose (FD) pharmacokinetic calculations can be used in these patients to determine an appropriate dosing regimen. We reviewed our experience with FD methods (12 patients) and CD methods (14 patients). Therapeutic levels were achieved more promptly in the FD group than in the CD group (44.4 +/- 8.1 vs. 97.1 +/- 12.5 hours; p < 0.005). Therapeutic serum concentrations were achieved with the first set of steady-state levels in 11% of CD patients and in 67% of FD patients (p < 0.005). The FD group required significantly fewer dosing changes (2.1 +/- 0.3) than did the CD group (3.7 +/- 0.7, p < 0.005). These data demonstrate that aminoglycoside dosing using first-dose pharmacokinetics results in improved maintenance of therapeutic serum concentrations compared with conventional methods in burn patients.

Adult↗
PubMed1991

Tracheal venous blood and lymph collection: a model to study airway injury in sheep.

Airway injury is a frequent result of the inhalation or aspiration of toxic material. Although upper airway damage can be identified endoscopically, pathophysiological changes are difficult to evaluate. This paper describes an animal model in which changes in tracheal blood and lymph flow rates, wet-to-dry weight ratios, and lymph-to-plasma protein ratios can be evaluated after injury. In this model, 12 cm of the cervical trachea were isolated using a double-cuffed endotracheal tube and injured with cotton smoke at near room temperature. Injury to the trachea was evaluated in twenty-five anesthetized sheep 4 (n = 3), 8 (n = 3), 24 (n = 3), 48 (n = 3), 96 (n = 3), and 192 (n = 2) h after smoke exposure and compared with sham control animals (n = 8). A significant increase in tracheal venous blood flow from 1.3 +/- 0.4 (SD) ml.min-1.cm-1 for the noninjured trachea to 2.8 +/- 1.2 was noted 24 h after injury (P less than 0.01). Lymph flow significantly increased from 1.3 +/- 0.4 microliters.min-1.cm-1 for the noninjured trachea to 9.8 +/- 3.3 24 h after injury while wet-to-dry weight ratios were elevated from 3.0 +/- 0.2 for noninjured trachea to 4.6 +/- 0.9 from 4 to 24 h after injury (P less than 0.01) and decreased to 3.7 +/- 0.5 by 96 h. Cast material consisting of airway exudate, cellular debris, and intact ciliated epithelial cells was both expectorated and found in the trachea when the animals were killed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Endotoxin (LPS) increases mesenteric vascular resistance (MVR) and bacterial translocation (BT).

Endotoxemia is responsible for many of the pathophysiologic alterations that occur with Gram-negative sepsis. We utilized a chronic ovine model to determine the hemodynamic disturbances in the gastrointestinal tract during endotoxemia. Sheep with indwelling arterial, venous, and pulmonary arterial catheters were used. An ultrasonic flow probe was placed on the cephalic mesenteric artery. The animals were subjected to: 1) Ringer's lactate infusion (sham n = 6); or 2) 1.5 mcg/kg E. coli endotoxin (n = 6) over over a period of one half hour and were monitored for 48 hours. They were then sacrificed and specimens of mesenteric lymph node, liver, spleen, kidney, and lung obtained for bacteriologic cultures and histologic analysis. Sheep receiving endotoxin showed more than 50% reduction in the mesenteric blood flow. Mesenteric vascular resistance increased while non-mesenteric systemic vascular resistance decreased. The increase in the total systemic vascular resistance, noted during endotoxemia, was thus likely due to the increase in the mesenteric vascular resistance. At autopsy there were positive cultures for microorganism in the mesenteric lymph nodes in six out of six sheep with endotoxemia as compared to one out of six of control. Thus the vasoconstriction in the mesenteric areas may have resulted in bacterial translocation from the GI tract.

Animals↗
PubMed1990

Selective permeability changes in the lungs and airways of sheep after toxic smoke inhalation.

The effect of toxic smoke inhalation on selective microvascular sieving of macro-molecules and lymph protein flux was assessed in adult sheep to determine whether the time course of microvascular dysfunction differs between the lung and trachea. Protein flux across the lung increased sixfold 48 h after inhalation of the products of incomplete cotton combustion, whereas tracheal protein flux increased fivefold 8 h after exposure and returned to near base line 48 h after exposure. The lung and trachea selectively retained some sieving to three different protein macromolecules with molecular radii of 36, 54, and 123 A. In the lungs the sieving selectivity for these macromolecules was least 48 h after injury, and in the trachea molecular selectivity was least 8 h after injury. These data suggest that the time course of microvascular injury differs for the trachea and the lung; microvascular changes are detected earlier in the trachea than in the lung. The inhalation injury described thus permits the characterization of the time course of airway and lung microvascular changes.

Animals↗
PubMed1990

A comparison of effects of thermal injury and smoke inhalation on bacterial translocation.

Thermal injury as well as smoke inhalation injury results in serious morbidity and high mortality. In a chronic ovine model, we studied the development of bacterial translocation to the mesenteric lymph node, liver, spleen, kidney, and lung following: 1) sham injury (N = 6), 2) cutaneous thermal injury (N = 5), 3) cotton smoke inhalation injury (N = 4), 4) combined thermal injury and smoke inhalation injury (N = 7). Cardiac output, mean arterial pressure, and plasma protein concentration were maintained within 10% of preinjury values. Urine output was maintained above 1 ml/kg/hour with fluid and plasma resuscitation. A wide-beam ultrasonic flow probe was chronically implanted to allow serial measurement of cephalic mesenteric arterial blood flow throughout the 48-hour experimental period. Sheep were sacrificed 48 hours following injury for quantitative organ culture of mesenteric lymph node, liver, spleen, kidney, and lung. Measurements of mesenteric blood flow demonstrated a decrease to 48 +/- 8%, 80 +/- 5%, and 64 +/- 9% of preinjury levels in sheep receiving thermal injury, smoke inhalation injury, and combination injury, respectively. The sham animals maintained mesenteric blood flow at 102 +/- 7% of control levels. Thermal injury, as well as combination thermal and smoke inhalation injury, resulted in higher levels of translocation than smoke inhalation injury alone.

Animals↗
PubMed1989

Development of oral-motor skills in the neurologically impaired child receiving non-oral feedings.

Treatment of children with swallowing dysfunction requires a holistic approach based on a global view of their problems and needs. The connection of the swallowing mechanism with the sensorimotor organization of postural tone and movement throughout the body is a critical factor in the evaluation and treatment of children whose dysphagia is rooted in a neurologic disorder. An appropriate program includes work with the development of movement skills, sensory processing, learning, social skills, and communication. The initial focus is placed on oral-motor treatment, rather than direct work on oral feeding. The primary goal of the program is to develop the appropriate use of the mouth, respiratory, and phonatory systems in exploration, sound play, and as much oral feeding as possible. Oral feeding is the by-product of a total program, not its major goal.

Child↗
PubMed1989

Morphological studies on the venous drainage of the trachea in the neck of sheep.

Systemic venous drainage of the cervical portion of the trachea from the cricoid cartilage to the sternal notch was observed in 50 adult sheep. In all animals, the first five to six tracheal rings starting at the cricoid cartilage were drained by the thyroid veins (v. thyroideae) bilaterally to the external jugular veins (v. jugularis externa). A venous complex draining the remaining cervical portion of the trachea was observed only on the left side of the trachea. This complex drained to the cranial vena cava (vena cava cranialis). India ink or Evans blue dye were infused into small vessels draining this area for verification. Variations in this venous complex were classified into three types based upon length of trachea drained. Type I was found in 26%, type II found in 58%, and type III found in 16% of the sheep studied and drained 23 +/- 5%, 58 +/- 11% and 78 +/- 10% of the cervical portion of the trachea, respectively. Blood flow from this area of the trachea was 85 +/- 28 mL/min/100 g wet issue. This study identified and classified the venous drainage of the cervical portion of the trachea in sheep.

Animals↗
PubMed1981

The role of complement and IgG on zymosan opsonization.

Zymosan particles require opsonization for optimal interaction with granulocytes and activation of their respiratory burst. In the present study we evaluated the serum factors necessary for zymosan opsonization. First, zymosan was treated with either normal serum or hypogammaglobulinemic serum (HGS), which is deficient in immunoglobulins (Ig) but has a normal concentration of complement components. Using granulocyte chemiluminescence to assay opsonization, the activity of particles treated with HGS was 66 +/- 1.9% (mean +/- SEM) of that with normal serum (p less than 0.001), suggesting a role of Ig. HGS opsonic activity was restored to normal when the particles were also treated with IgG; however, neither heat-inactivated normal serum (56 degrees C, 30 min) nor pure human IgG alone had opsonic activity. The roles of the classical (CCP) and alternative (ACP) pathways of the complement system were also investigated. ACP activity seemed essential, since inactivation of the ACP (50 degrees C, 30 min) eliminated the activity of normal serum. However, when the ACP was intact, CCP action appeared to participate in opsonization, since selective CCP inactivation with EGTA and MgCl2 reduced the opsonic activity of normal serum by 26 +/- 3.3% (p less than 0.005). Thus, it is concluded that the ACP, CCP, and IgG all participate in zymosan opsonization.

Agammaglobulinemia↗
PubMed1978

Comparison of plasma hormone changes using a "conventional" and a "paper" pill formulation of a low-dose oral contraceptive.

Two formulations of a low-dose oral contraceptive (Microgynon: 150 microgram of levonorgestrel [NG] +30 micrograms of ethynylestradiol [EE2]) were studied. The first was the "conventional" pill; the second was a "paper" pill prepared by evaporation of aliquots of a solution of the component steroids onto squares of edible cellulose separated by perforations, similar to a sheet of postage stamps. The effects of the two formulations on plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17beta-estradiol (E2), and progesterone were compared. Samples of blood were obtained from five women during a treatment period on the "conventional" pill and from five on the "paper" pill. When possible, blood samples were also obtained from a "control" cycle of each of these female subjects. Plasma LH, FSH, E2, and progesterone levels were determined by specific radioimmunoassay methods during control and treatment periods and NG and EE2 levels during treatment periods. Eight-hour plasma profiles for NG and EE2 at the beginning and in the later stage of the treatment periods were obtained and these samples were also analyzed for LH, FSH, E2, and progesterone. Results showed that with one exceptcrogynon were equally effective in suppressing ovulation. As in a previous study, FSH levels appeared to be one of the most sensitive indices of suppression.

Adult↗
PubMed1976

Studies on low-dose oral contraceptives: cervical mucus and plasma hormone changes in relation to circulating D-norgestrel and 17alpha ethynyl-estradiol concentrations.

A study was undertaken to determine the effects of a low-dose oral contraceptive comprising 150 mug of D-norgestrel and 30 mug of 17alpha-ethynyl estradiol (Microgynon) on the plasma levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), 17BETA-ESTRADIOL, AND PROGESTERONE AND ON THE PHYSICAl properties of cervical mucus. Samples of blood and cervical mucus were obtained from three women during a treated cycle and the immediately-following "withdrawal" cycle. Specific radioimmunoassay methods were used to determine LH, FSH, 17beta-estradiol, and progesterone levels in treated and withdrawal cycles, and D-norgestrel and 17alpha-ethynyl estradiol in samples obtained during treated cycles. The concentration of synthetic steroids was also measured in blood samples obtained before and 1 hour after ingestion of the contraceptive to determine the maximal daily variation. The results indicated that the contraceptive action of this combined low-dose oral contraceptive is mediated through suppression of ovulation and by rendering the cervical mucus impenetrable to sperm. Plasma FSH levels appeared to be one of the most sensitive indices of suppression. Determination of D-norgestrel and 17alpha-ethynyl estradiol showed that 3 to 4 days were required to reach maximal plasma levels and that daily fluctuations were considerable. Withdrawal of the pill resulted in an immediate return to ovulatory cycles in all three subjects studied.

Biological Clocks↗