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Biomedical subjects

H Yates

Publications and source records attributed to H Yates.

6 recordsLinked to original sources
PubMed2003

Fine mapping of quantitative trait loci for improved fruit characteristics from Lycopersicon chmielewskii chromosome 1.

The near-isogenic line (NIL) TA1150 contains a 56-cM introgression from Lycopersicon chmielewskii chromosome 1 and has several interesting phenotypic characteristics including fruit with orange color, high levels of soluble solids, thick pericarp, small stem scars, and good firmness. A set of overlapping recombinant lines (subNILs) was developed and field tested to fine map the quantitative trait loci (QTL) controlling these traits. The results indicated that the solids, pericarp thickness, and firmness QTL are distinct from the color locus. Several of the QTL mapped in this study, including the soluble-solids QTL, probably correspond to QTL mapped in other wild species of tomato. However, analysis of a set of TA523 subNILs containing complementary introgressions from Lycopesicon hirsutum chromosome 1 suggests that this wild species may contain a different locus for improved soluble solids. Thus, it might be possible to combine the L. chmielewskii and L. hirsutum alleles for these loci in a single line with the potential for extremely highly soluble solids. The TA1150 subNIL TA1688 contains the smallest introgression of the solids locus (approximately 19 cM), as well as the pericarp thickness and firmness QTL, with a yield that was equivalent to two of the three control lines. Isolation of recombinant subNILs from TA1688 should break the linkage between orange color and high solids and provide a small introgressed segment for marker-assisted breeding and genetic improvement of processing tomato.

Alleles↗
PubMed1994

Incidence and perioperative management of tension pneumocephalus following craniofacial resection.

This study is a retrospective review to evaluate factors associated with the risk of pneumocephalus following craniofacial resection and the management of tension pneumocephalus. Twenty-two craniofacial operative procedures were reviewed in 18 patients entered into the Neurosciences Critical Care Unit, Johns Hopkins Hospital, during a 54 month period, from 1986-1991. Pneumocephalus developed after 7 of 22 operations; of these seven, two developed tension pneumocephalus. The use of lumbar cerebral spinal fluid (CSF) drainage during the operation correlated most strongly with the development of pneumocephalus. The diagnosis of esthesioblastoma also correlated significantly. Both episodes of tension pneumocephalus occurred after craniofacial resection in which lumbar drainage of CSF was performed. Tension pneumocephalus was successfully treated in these two patients with a combination of air evacuation and medical management of raised intracranial pressure. Transient diabetes insipidus developed in both patients. The risk of pneumocephalus following craniofacial procedures is significant, and may be increased by the use of lumbar drainage of CSF intraoperatively. Rapid neurologic deterioration following craniofacial resection may be caused by the development of tension pneumocephalus. Early diagnosis of tension pneumocephalus and aggressive management of raised intracranial pressure may be important in preventing serious neurological complications.

Adult↗
PubMed1994

Efficacy of breathing and coughing exercises in the prevention of pulmonary complications after coronary artery surgery.

One hundred twenty patients undergoing coronary artery surgery completed a randomized controlled study designed to investigate whether prophylactic chest physiotherapy affected the incidence of postoperative pulmonary complications. Group 1 patients received no preoperative or postoperative chest physiotherapy. Group 2 patients received preoperative education and instruction in breathing and coughing exercises and postoperative supervision and assistance in performing the same. These exercises were supervised by a physiotherapist twice per day on the first 2 postoperative days and once per day on the 3rd and 4th postoperative days. Physiotherapy for group 3 patients was the same as for group 2 patients except that patients were seen by a physiotherapist 4 times per day on the first 2 postoperative days and twice per day on the 3rd and 4th postoperative days. Group 2 and 3 patients were instructed to practice breathing and coughing exercises every hour. Overall, an incidence of clinically significant postoperative pulmonary complications of 7.5 percent was demonstrated. In general, these patients demonstrated lower levels of preoperative pulmonary function and very low early postoperative oxygenation compared with those who did not develop pulmonary complications. There was no indication that the incidence or severity of fever, hypoxemia, chest roentgenologic abnormalities or clinically significant postoperative pulmonary complications was different between groups. These results suggest that the necessity for prophylactic chest physiotherapy after routine coronary artery surgery should be reviewed.

Breathing Exercises↗
PubMed1993

Perioperative morbidity in patients randomized to epidural or general anesthesia for lower extremity vascular surgery. Perioperative Ischemia Randomized Anesthesia Trial Study Group.

BACKGROUND: Perioperative morbidity may be modifiable in high risk patients by the anesthesiologist's choice of either regional or general anesthesia. This clinical trial compared outcomes between epidural (EA) and general (GA) anesthesia/analgesia regimens in a group of patients at high risk for cardiac and other morbidity who were undergoing similarly stressful surgical procedures. METHODS: One hundred patients scheduled for elective vascular reconstruction of the lower extremities were randomized to receive either EA for surgery followed by epidural analgesia, or GA for surgery followed by intravenous patient-controlled analgesia. Hemodynamic monitoring, blood pressure, and heart rate limits were determined prior to randomization. Management of anesthesia in the immediate postoperative period was standardized. The data collected included continuous electrocardiographic monitoring from the day before surgery through the third postoperative day, serial electrocardiograms, and cardiac enzymes. Cardiac ischemia, myocardial infarction, unstable angina, and cardiac death were identified by a cardiologist blinded to the type of anesthesia received. Other major morbidity was determined at the time of hospital discharge and at 1 and 6 months after surgery. RESULTS: Eleven patients who received GA required regrafting or an embolectomy during their hospital stay, compared with two patients who received EA. This association of GA with reoperation remained significant after adjustment for baseline differences. Cardiac outcomes were similar in the two groups with respect to perioperative death (1 EA and 1 GA), death within 6 months (4 EA and 3 GA), nonfatal myocardial infarction within 7 days (2 EA and 2 GA), unstable angina (0 EA and 2 GA), and myocardial ischemia following randomization (17 EA and 23 GA). Rates of major infections in the two groups (1 EA and 2 GA), renal failure (3 EA and 3 GA), and pulmonary complications (3 EA and 7 GA) also were similar. CONCLUSIONS: Carefully conducted epidural and general anesthesia appear to be associated with comparable rates of cardiac and most other morbidity in patients undergoing lower extremity vascular surgery. However, compared with general anesthesia, epidural anesthesia is associated with a lower incidence of reoperation for inadequate tissue perfusion and, therefore, may be advantageous for this surgical population.

Aged↗
PubMed1993

Determinants of catecholamine and cortisol responses to lower extremity revascularization. The PIRAT Study Group.

BACKGROUND: Surgical trauma elicits diffuse changes in hormonal secretion and autonomic nervous system activity. Despite studies demonstrating modulation of the stress response by different anesthetic/analgesic regimens, little is known regarding the determinants of catecholamine and cortisol responses to surgery. METHODS: Plasma catecholamines and cortisol secretion data were obtained from 60 patients undergoing lower extremity revascularization. Patients were randomized to receive either general anesthesia combined with patient-controlled intravenous morphine (GA) or epidural anesthesia combined with epidural fentanyl analgesia (RA). All aspects of intra- and postoperative clinical care were defined by written protocol. Plasma catecholamines were measured before induction, intraoperatively, and for the first 18 h postoperatively (by HPLC). Urine cortisol was measured intra- and postoperatively using RIA. Data were evaluated using univariate and multivariate analyses to evaluate demographic and perioperative variables as determinants of stress hormone secretion. RESULTS: Plasma catecholamines increased during skin closure in the GA group, and remained higher relative to the RA group in the postoperative period. Multivariate analysis indicated that age and anesthetic regimen predicted increases in catecholamines during skin closure (P < 0.005), although duration of surgery, blood loss, and body temperature were not correlated. Early postoperative norepinephrine concentrations were correlated with pain score and duration of surgery (P < 0.004), but not with anesthetic management, blood loss, or body temperature. All postoperative norepinephrine levels were highly correlated (r = 0.7) with norepinephrine levels during skin closure. Cortisol excretion was higher postoperatively than intraoperatively. No patient or perioperative variable predicted cortisol excretion, and cortisol excretion was not correlated with catecholamine levels at any time. CONCLUSIONS: These data indicate that patient factors, such as age and inherent sympathetic responsivity, are important determinants of the catecholamine response to surgery. Modulation of the norepinephrine response by regional anesthesia/analgesia appears to be related, in part, to superior analgesia. The lack of correlation between catecholamine and cortisol secretion indicates that the stress response may consist of discrete systems responding to different stimuli.

Adult↗