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Biomedical subjects

J Bartlett

Publications and source records attributed to J Bartlett.

At least 19 recordsLinked to original sources
PubMed1992

Effects of mitral regurgitation on pulmonary venous flow and left atrial pressure: an intraoperative transesophageal echocardiographic study.

OBJECTIVES AND BACKGROUND: Pulmonary venous flows recorded by pulsed wave Doppler transesophageal echocardiography examination can be used to assess the severity of mitral regurgitation. Pulmonary venous flows are also related to left atrial pressures; however, the determinants of these flows have yet to be characterized in the presence of mitral regurgitation. METHODS: We simultaneously recorded intraoperative pulmonary venous flows by transesophageal echocardiography and left atrial pressures by direct left atrial puncture in 16 patients with different grades of mitral regurgitation: 2+ (n = 5), 3+ (n = 4) and 4+ (n = 7). Pulmonary venous peak systolic and diastolic flow velocities and peak reversed systolic flow velocities were compared with left atrial pressure a and v waves, a-x and v-y descent values and left atrial volumes. RESULTS: Pulmonary venous systolic to diastolic flow ratios correlated with decreases in left atrial pressure a/v ratios and with increases in the v waves of patients with higher grades of mitral regurgitation. Univariate analysis revealed that the best determinants of the pulmonary venous systolic to diastolic flow ratio were the left atrial pressure v wave (r = -0.76), the v-y descent value (r = -0.73) and the a/v ratio (r = 0.71). Lower correlations were found for left atrial end-systolic (r = -0.48) and end-diastolic (r = -0.42) volumes. Reversed systolic flow was present in patients with 4+ mitral regurgitation, despite left atrial enlargement. CONCLUSIONS: Pulmonary venous flow can be used to assess the severity of mitral regurgitation and reflects the effects of mitral regurgitation severity on the left atrial pressure a and v waves.

Adult↗
PubMed1992

Evaluation of new anti-infective drugs for the treatment of intraabdominal infections. Infectious Diseases Society of America and the Food and Drug Administration.

These guidelines deal with the evaluation of anti-infective drugs for the treatment of intraabdominal infections. The clinical entities consist of infections arising from any part of the gastrointestinal tract, from the distal esophagus to the colon. These include surgical infections of the bowel, biliary tree, liver, spleen, and pancreas. Virtually all intraabdominal infections are due to multiple microorganisms resident in the gastrointestinal tract; these include aerobes and facultative and obligate anaerobes. Infections are classified as complicated (requiring an operative procedure), uncomplicated (managed medically), and postoperative wound (the operative procedure should be curative, but anti-infective drugs are used to prevent further infection at the site). Clinical criteria are paramount for entry into a study and for evaluation of efficacy. For complicated infections an adequate operation is an important determinant of outcome and needs assessment. Cultures of purulent intraabdominal fluid or abscess material are the only valid microbiologic indicators of infection. The acute physiology and chronic health evaluation score is useful in defining the severity of acute illness. The control regimen should consist of effective, established drugs and surgical procedures for the condition. Duration of therapy for complicated infections is usually 5-14 days; for uncomplicated infections, 3-7 days; and for postoperative wound infection, 2-5 days. Periodic assessment of safety and efficacy must be conducted during therapy. The outcome at final assessment is cure, failure, or indeterminate.

Anti-Infective Agents↗
PubMed1991

Ditiocarb sodium (diethyldithiocarbamate) therapy in patients with symptomatic HIV infection and AIDS. A randomized, double-blind, placebo-controlled, multicenter study.

We randomized 389 symptomatic patients with human immunodeficiency virus (HIV) infection to ditiocarb sodium (400 mg/m2 orally for 24 weeks) or a placebo. Patients were well balanced according to Centers for Disease Control (CDC) group, CD4+ cell number, and duration of disease prior to entry. Ten new acquired immunodeficiency syndrome (AIDS)-defining opportunistic infections occurred in the treated patients and 21 in the controls. Reduction of new opportunistic infections in the ditiocarb group was significant in all patients (relative risk [RR], 0.44) and in patients with AIDS (CDC groups IV-C1 and IV-D) (RR, 0.12). The size of the effect of ditiocarb was maintained when data were reanalyzed after exclusion of a patient who progressed to Pneumocystis carinii pneumonia who was not strictly CDC-defined (RR, 0.46), or when considering as new opportunistic infections three events, which were clinically active at entry, but for which the definitive diagnosis was made during study (RR, 0.49). The administration of ditiocarb did not induce any major adverse clinical or biological reactions. We conclude that, in this study, ditiocarb was safe and reduced the incidence of opportunistic infections in patients with symptomatic HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Control of anthocyanin biosynthesis in flowers of Antirrhinum majus.

The intensity and pattern of anthocyanin biosynthesis in Antirrhinum flowers is controlled by several genes. We have isolated six cDNA clones encoding enzymes in the pathway committed to flavonoid biosynthesis and used these to assay how the regulatory genes that modify colour pattern affect the expression of biosynthetic genes. The biosynthetic genes of the later part of the pathway appear to be co-ordinately regulated by two genes, Delila (Del), and Eluta (El), while the early steps (which also lead to flavone synthesis) are controlled differently. This division of control is not the same as control of anthocyanin biosynthesis by the regulatory genes R (S) and C1 in maize aleurone, and may result from the adaptive significance of different flavonoids in flowers and seeds, reflecting their attractiveness to insects and mammals respectively. El and del are probably involved in transcriptional control and both genes appear to be able to repress expression of some biosynthetic genes and activate expression of others.

Anthocyanins↗
PubMed1988

Characterization of a factor from human ovarian follicular fluid which stimulates Leydig cell testosterone production.

A factor from human ovarian follicular fluid (hFF) has been characterized which stimulates testosterone production of human, rat, mouse and hamster Leydig cells. hFF was obtained from women participating in an in vitro fertilization programme. Basal and hCG stimulated testosterone production of rat interstitial cells, and Percoll purified Leydig cells were significantly stimulated by hFF. The steroidogenic response of the cells was 3-5 fold higher than that obtained after stimulation with maximal doses of hCG. A serum pool from the same patients was found to be about 30 times less potent than hFF in stimulating steroidogenesis. The stimulatory activity was retained after precipitation with ammonium sulphate and dialysis. Precipitation with ethanol, ether and acetone resulted in a partial loss of activity, whereas extraction with charcoal or heating at 100 degrees C for 10 min resulted in significant loss of activity. When hFF was fractionated by gel chromatography, the stimulatory activity was eluted in a molecular weight region between 30 and 50 kD. The stimulatory factor was further purified by chromatofocusing and was eluted as a homogeneous peak with an isoelectric point between 8.8 and 9.5. The SDS-PAGE analysis of these fractions, however, revealed that the active substance was not homogeneous. The purified factor was immunologically distinct from hCG and hLH. These studies demonstrate for the first time the presence of a factor in the hFF which may potentiate the action of LH in the ovary.

Animals↗
PubMed1987

Norfloxacin for prevention of bacterial infections in granulocytopenic patients.

The efficacy and safety of norfloxacin were compared with those of placebo, vancomycin-polymyxin, and trimethoprim-sulfamethoxazole (TMP/SMX) for prophylaxis of bacterial infections in granulocytopenic patients. The study results showed that norfloxacin treatment, which was well tolerated and not associated with any serious systemic adverse effects, prevented acquisition of gram-negative bacillary organisms. Fewer norfloxacin-treated patients (38 of 108 patients, or 35 percent) experienced microbiologically documented infections compared with patients receiving placebo (27 of 40 patients, or 68 percent), vancomycin-polymyxin (16 of 30 patients, or 53 percent), or TMP/SMX (14 of 28 patients, or 50 percent). Gram-negative bacteremia developed in five of 108 norfloxacin-treated patients (5 percent), compared with 17 of 40 placebo-treated patients (43 percent), five of 30 treated with vancomycin-polymyxin (17 percent), and one of 28 patients treated with TMP/SMX (4 percent). The incidence of gram-positive bacteremia was similar in all study groups and was not affected by norfloxacin or any other oral prophylactic antibiotics. These results suggest that norfloxacin is both safe and effective for the prevention of serious gram-negative bacillary infections in granulocytopenic patients. More effective prophylaxis of gram-positive bacterial infections, however, is needed.

Adolescent↗
PubMed1982

Infectious gastroenteritis in bone-marrow-transplant recipients.

We prospectively evaluated infections with several gastrointestinal pathogens in patients undergoing bone-marrow transplantation, in an attempt to correlate infection with morbidity and mortality. Thirty-one of 78 patients (40 per cent) were infected with one or more of the following enteric pathogens during the study: adenovirus (12 infections), rotavirus (nine), coxsackievirus (four), or Clostridium difficile (12). Several patients were infected with more than one pathogen. Infection correlated with the occurrence of diarrhea and abdominal cramps. The mortality rate among the infected patients was 55 per cent--significantly higher than the rate (13 per cent) among the noninfected patients (P less than 0.001). This study indicates that enteric pathogens that often cause mild diarrhea in normal populations can cause serious infections in marrow-transplant recipients. Measures aimed at preventing or treating such infections might reduce the morbidity and mortality associated with marrow transplantation.

Adult↗
PubMed1982

Cardiac sequelae of acute head injury.

An intensive 72 hour study of the cardiovascular effects of severe diffuse brain injury was made in seven patients. No other major injury was present. Patients received optimal care very rapidly after injury and intracranial pressure, which was continuously monitored, was maintained at or just above normal by elective positive pressure ventilation techniques. Three patients showed evidence of progressive myocardial ischaemia on continuous electrocardiographic monitoring. Two of these patients died. Ventricular arrhythmias were uncommon but one of the patients with ischaemia developed ventricular tachycardia. Heart rate patterns were very abnormal but did not predict complications. Blood pressure did not vary greatly and cardiac outputs were usually normal. Pronounced excesses of urinary catecholamines and serum creatine kinase 2 isoenzyme (CK MB) as well as total creatine kinase were found. Histological evidence of myocardial damage could be shown at necropsy in the one case whose heart was available for study. This study shows that the cardiac effects of isolated diffuse cerebral injury may be harmful and even fatal despite correction of secondary factors such as anoxia and raised intracranial pressure. The findings suggest that evaluation of the potential benefits of sympathetic blockade is warranted. Cardiac complications of cerebral damage deserve wider recognition by intensive care personnel, neurologists, and neurosurgeons.

Adolescent↗
PubMed1981

Some patients with cerebral aneurysms are deficient in type III collagen.

Polyacrylamide gel electrophoresis of pepsin-digested skin biopsy specimens and carboxymethyl cellulose chromatography of radioactively labelled collagens produced by cultured fibroblasts demonstrated that 7 of 12 patients with congenital cerebral aneurysms were type III collagen deficient. This suggests that some cerebral aneurysms resemble various inherited defects of connective tissue-i.e., Ehlers-Danlos syndrome type IV-in which type III collagen deficiency causes arterial fragility.

Cerebral Hemorrhage↗
PubMed1981

Beta-adrenoceptor blockers and the blood-brian barrier.

1 This study on 21 neurosurgical patients was set up to investigate the extent to which four chronically administered beta-adrenoceptor blockers, propranolol, oxprenolol, metoprolol and atenolol, cross and blood-brain barrier and enter the cerebrospinal fluid (CSF) and brain tissue. The concentration in the CSF of the three lipophilic beta-adrenoceptor blockers, propranolol, oxprenolol and metoprolol, approximated to the free drug concentration in the plasma, and was a poor predictor of brain concentration. These three lipophilic beta-adrenoceptor blockers appeared in brain tissue at concentrations 10-20 times greater than that of hydrophilic atenolol. The approximate brain/plasma ratio for propranolol was 26, for oxprenolol 50, for metoprolol 12 and for atenolol 0.2. 2 The low concentration of atenolol in brain tissue is possibly responsible for the low incidence of central nervous system-related side effects in patients on this agent compared to lipophilic beta-adrenoceptor blockers.

Adrenergic beta-Antagonists↗
PubMed1981

Quantitative transcervical uterine cultures with a new device.

This study was initiated to examine the ability of a new device to take transcervical cultures of the endometrial cavity in the normal and postpartum uterus. Quantitative bacteriologic assessments were made. The results show there is a millionfold increase in the mean concentration of bacteria cultured from the infected puerperal uterus when contrasted with cultures from nonpregnant women and those who have just undergone repeat cesarean section. The authors conclude that the new device obtains cultures transcervically with marked reduction in contamination; however, some method for quantification of bacterial populations must complement the culture so that results differentiate between colonization and infection.

Bacteriological Techniques↗
PubMed1980

Quantitative bacteriology of endodontic infections.

A technique is described for obtaining quantitative cultures of endodontic specimens. Paper point samplings were placed in a diluted salt solution, vortexed, and then cultured quantitatively using serial dilutions plated onto multiple media. Specimen weight was determined by weighing the point before and after specimen collection. This method was used in 10 nonvital teeth and showed a mean concentration of 10(7.7) bacteria per gram of sample. Nine specimens yielded a mixed aerobic-anaerobic flora, and there was an average of five different bacterial species per specimen in concentrations exceeding 10(5)/gm.

Anaerobiosis↗