Biomedical subjects

M A Greene

Publications and source records attributed to M A Greene.

16 recordsLinked to original sources

PubMed1995

Unilateral pulmonary agenesis, esophageal atresia, and distal tracheoesophageal fistula.

A small-for-gestational-age, premature infant with the combination of unilateral pulmonary agenesis, esophageal atresia, and distal tracheoesophageal fistula was treated successfully by early gastrostomy and delayed fistula division with esophagoesophagostomy. Only 2 other successfully treated cases have been reported previously. Both were full-term infants treated with early division of the tracheoesophageal fistula and esophagoesophagostomy. Gestational age, size, and associated medical problems need to be considered when planning operative therapy for these babies.

Abnormalities, Multiple↗

PubMed1995

Resistance and modes of communication.

The recognition that there are three modes of thinking and communicating--iconic, enactive, and symbolic--clarifies and simplifies many issues in psychoanalytic theory and technique. Although this concept is applicable to all communication, it is particularly important in understanding and interpreting various types of resistance. The author uses a number of vignettes to illustrate the forms and functions of various types of nonverbal communication within the psychoanalytic process.

Adult↗

PubMed1994

The changing strategies in operation for transposition of the great vessels.

Between July 3, 1985, and February 24, 1994, a total of 55 infants underwent arterial switch procedures for the repair of transposition of the great vessels. Thirty-five infants had an intact ventricular septum and 20 had ventricular septal defects. To date, there have been three late deaths, one in the group with an intact ventricular septum and two in the group with a ventricular septal defect. Early postoperative complications included atrial dysrhythmias, prolonged ventilation, inability to close the sternum, and tension on the coronary arteries. Follow-up echocardiographic data for 44 patients indicate that pulmonary artery gradients are a worrisome postoperative problem, especially in infants who have ventricular septal defects.

Child, Preschool↗

PubMed1994

Avascular necrosis of the first metatarsal head: incidence in distal osteotomy combined with lateral soft tissue release.

The incidence of avascular necrosis of the metatarsal head following distal first metatarsal osteotomy combined with adductor tendon release has not been documented in a large series of patients. Of 82 consecutive procedures in 64 patients performed between 1986 and 1988, 42 patients (58 procedures) were available for clinical and radiographic examination. Average follow-up was 2.5 years (range 1.0-4.2 years). There were 35 L-shaped and 23 chevron osteotomies which were combined with a lateral soft tissue release that included adductor tenotomy. Preoperative hallux valgus angle averaged 25 degrees (range 15-40 degrees), and intermetatarsal angle averaged 12 degrees (range 5-24 degrees). Follow-up amount of correction averaged 13 degrees and 5 degrees, respectively. Eighty-four percent of patients were satisfied with their result. There was one case of avascular necrosis. The patient was asymptomatic at 4.2 years' follow-up, and the remaining patients included two with infections, one hallux varus, and no nonunions.

Adult↗

PubMed1993

Laparotomy wound closure with absorbable polyglycolic acid mesh.

A knitted mesh of polyglycolic acid was used successfully in 59 critically ill patients to bridge abdominal wall defects and prevent evisceration after celiotomy. Polyglycolic acid knit mesh was used in 31 patients who had extraordinary visceral edema after resuscitation and the mesh was inserted to avoid excessive tension in the wound closure, 15 patients who had abdominal wall defects after adequate débridement for necrotizing fasciitis, and 13 patients who had losses of abdominal wall tissue caused by trauma or after resection of tumor. There were 14 hospital deaths among the seriously ill patients. Thirteen patients had enterocutaneous fistulas, seven of which occurred after meshes were inserted. The mesh material was strong, pliable and easily inserted in large abdominal wall defects. The polyglycolic acid knit mesh was infiltrated by granulation tissue within three weeks, including in heavily contaminated wounds. Two to three months after insertion, the material was absorbed. Hernia defects were common four to six months after the meshes were inserted and repairs were performed electively after patients had recovered from the primary problems. We conclude that absorbable polyglycolic acid knit mesh can be a useful technique for quickly achieving a secure tension-free closure of abdominal wounds.

Humans↗

PubMed1991

Emergency aortocoronary bypass after failed angioplasty.

One thousand two hundred fourteen percutaneous transluminal coronary angioplasties were performed over a 38-month period. Sixty patients required immediate emergency coronary artery bypass grafting after angioplasty failure; 7 of these had evidence of acute myocardial infarction before angioplasty and were excluded from the study. Of the 53 patients remaining, 27 (51%) had electrocardiographic and enzyme evidence of postoperative myocardial infarction. Two patients died (4%), and 10 had postoperative complications (19%). No statistical significance was noted comparing age, sex, incidence of prior myocardial infarction or myocardial dysfunction, time for revascularization, or average number of grafts completed in those with single-vessel (n = 21) versus multiple-vessel (n = 32) coronary artery disease. Postoperatively, those with multiple-vessel disease required intraaortic balloon pump support (p = 0.06) and antiarrhythmic medications more frequently than single-vessel patients (p less than 0.01) and had a higher complication rate (p less than 0.05). Although not reaching statistical significance, the data also suggest a higher death and postoperative myocardial infarction rate in patients with multiple-vessel disease. Emergency coronary artery bypass grafting after failed percutaneous transluminal coronary angioplasty carries a higher morbidity and mortality than elective coronary artery bypass grafting, particularly for patients with multiple-vessel coronary artery disease.

Aged↗

PubMed1989

Electrophysiological effects of cocaine in the mesoaccumbens dopamine system: repeated administration.

Behavioral evidence indicates that the potent rewarding effects of cocaine are mediated, in part, by the mesoaccumbens dopamine (DA) system projecting from A10 DA cells in the ventral tegmental area (VTA) to the nucleus accumbens (NAc). Previous electrophysiological studies from our laboratory have indicated that cocaine (i.v.) exerts inhibitory effects on A10 DA neurons, due to enhanced stimulation by DA at DA autoreceptors are well as by activation of NAc-VTA feedback pathways. In the present experiments, extracellular single-unit recording and microiontophoretic techniques were used to determine the possible alterations in the mesoaccumbens DA system after repeated cocaine administration. Twice daily injections of cocaine (10 mg/kg i.p., 14 days) caused significant subsensitivity to the inhibitory effects of low i.v. doses of the DA agonist apomorphine in comparison to rats receiving similar treatments with saline or procaine. Iontophoretic application of DA to A10 DA neurons in rats treated repeatedly with cocaine (2X10 mg/kg, 14 days) also produced significantly less inhibition as compared to control rats. Cell population analysis of the VTA revealed that autoreceptor subsensitivity in cocaine-treated rats resulted in a significantly greater number of spontaneously active A10 DA neurons, and a significantly higher firing rate as compared to A10 DA neurons in control rats. In striking contrast to A10 DA cells, recordings from NAc neurons in cocaine-treated rats (2X10 mg/kg, 14 days) indicated that these cells were supersensitive to the inhibitory effects of iontophoretic DA. Although the mechanism underlying such supersensitivity remains unclear, the increased sensitivity of postsynaptic NAc DA receptors combined with the subsensitivity of A10 DA autoreceptors could lead to greatly enhanced DA transmission and may help to explain some aspects of cocaine-induced behavioral sensitization.

Animals↗

PubMed1988

Trauma associated with three and four-wheeled all-terrain vehicles.

Death or serious injury may occur as the result of accidents involving three- and four-wheeled recreational vehicles. Thirty-two cases of such trauma requiring hospitalization at the University of Missouri Hospital were reviewed, and followup questionnaires sent to each patient. Head and extremity trauma was nine times as frequent as torso injuries. Males were injured in 81% of the cases, and the average age of all patients was 18.6 years. Fifty per cent required intensive-care monitoring and 74% required surgery. Two patients died of head injuries. Of the 25 survivors who responded to the questionnaires, 44% reported either inability to return to work or substantial interference with daily living due to their injuries. Inexperience riding the vehicle, prior use of alcohol, and lack of protective riding apparel were frequently cited as contributing factors in these injuries.

Adolescent↗

PubMed1986

Mucus transport in the airways by two-phase gas-liquid flow mechanism: continuous flow model.

Mucus transport speed induced by two-phase gas-liquid interaction was measured in the continuous two-phase annular flow tube models, and factors influencing the transport speed were assessed in conjunction with rheological properties of mucus. The flow model was made with 1.0-cm-ID glass tubes and positioned either vertically or horizontally. During a continuous passage of airflow through the model tube, mucus stimulants were supplied into the tube at a rate of 0.5-2.0 ml/min. The advancing speed of the leading edge of the mucous layer and mean mucous layer thickness were then measured. The transport speed in the vertical tube model ranged from 1.1 to 3.1 cm/min with a mucus feed rate of 0.5 ml/min at airflow rates of 0.33-1.17 l/s and increased with increasing airflow rates but decreased rapidly with increasing viscosity of mucus. The transport speed increased almost proportionally with increasing mucus feed rate. Elasticity of mucus did not affect the transport speed itself. However, more elastic mucus caused lower flow resistance and thereby could be transported with a much reduced work load. The transport speed in the horizontal tube model was 5-60% faster than that in the vertical tube model. The mean mucous layer thickness in the vertical tube model was found to be in the range of 0.5-1.5 mm in the experimental conditions used, and decreased rapidly with increasing airflow rate and decreasing viscosity of mucus. From these data the transport speed could be functionally related to airway diameter, mucous layer thickness, and mucus production rate.

Biological Transport↗

PubMed1984