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Biomedical subjects

R W Martin

Publications and source records attributed to R W Martin.

At least 109 records · Page 6Linked to original sources
PubMed1992

Adjunctive antibiotic treatment of women with preterm rupture of membranes or preterm labor.

Subclinical infection is associated with preterm rupture of the membranes (PROM) and preterm labor (PTL) in many cases. It was hypothesized that antibiotic treatment might delay delivery and/or decrease infectious morbidity in those with PROM or PTL. Patients from 19 to 34 weeks with PROM and no labor or PTL with intact membranes (but not both) were separately randomized to receive ampicillin versus placebo in addition to usual therapy. There were 36 women with PTL (21 ampicillin/15 placebo) and 84 with preterm PROM (41 ampicillin/43 placebo). Demographically, the treatment and placebo groups were similar. Outcome variables analyzed included delivery delay after treatment, maternal chorioamnionitis/endometritis, Apgar score, neonatal infection, or respiratory distress, and hospital stay. There were no significant differences between the ampicillin and placebo groups in those with PTL or preterm PROM as it concerned outcome parameters. Adjunctive ampicillin used for treatment of idiopathic PTL or preterm PROM was not beneficial in this study.

Adult↗
PubMed1992

Clinical application of linear ultrasound probes.

The linear ultrasound probe should be viewed as an adjunct to conventional endoscopic ultrasonography with combined ultrasound endoscopes. It certainly does not replace these instruments for staging neoplasms and imaging extraintestinal organs such as the pancreas. It can be a simpler alternative to these instruments when applied at the time of endoscopy to obtain more information about wall thickness and the cause of an intramural mass. It can add information when used to image within impassable malignant strictures. Further development of the linear probes with the addition of a balloon over the transducer and the advent of new probes that utilize other scanning mechanisms is anticipated and should make this imaging system even more useful.

Endoscopy↗
PubMed1992

Reduction in adherence of Actinomyces viscosus after exposure to low-frequency acoustic energy.

The ability of low-frequency (200 Hz) acoustic energy to reduce the adherence of Actinomyces viscosus T14V to saliva-treated hydroxyapatite (SHA) disks was studied. An acoustic pressure range between 0 and 65 kPa and exposure durations between 0 and 8 min were used to study the levels necessary to significantly alter adherence. The effects of acoustic exposure on both bacteria in liquid and bacteria already adhering to SHA disks were studied. A modified enzyme-linked immunosorbent assay was used to assess bacterial adherence. For bacterial suspensions exposed prior to addition to SHA disks, it was found that reductions in adherence were greater for lower bacterial concentrations. Exposure of bacteria already adhering to SHA disks resulted in a decrease in adherence that was independent of the bacterial concentration and linearly related to the logarithm of the exposure duration. In addition to affecting adherence, acoustic energy also dispersed bacterial aggregates. Our results support the concept that low-frequency sonic energy applied orally may be of therapeutic value in reducing adherence and colonization of teeth by plaque bacteria.

Acoustic Stimulation↗
PubMed1992

Trial of labor after cesarean delivery: experience in the non-university level II regional hospital setting.

OBJECTIVE: We sought to determine the extent to which vaginal birth after cesarean delivery was attempted since 1987 or 1988 in a representative sample of three regional level II hospitals in Mississippi. METHODS: The medical record department in each hospital identified all potential study subjects for this retrospective case series. One author abstracted relevant information from each medical record and entered it into a relational data base. RESULTS: Among 18,703 live births, 1574 patients had previous abdominal delivery (8.4%). Trial of labor was undertaken in 286 patients (18%), with an overall successful vaginal delivery rate of 71%. Although success rates for the three level II hospitals were similar (63-81%), utilization rates varied considerably (7-40%). One uterine dehiscence led to hysterectomy; otherwise, there were no serious perinatal complications or differences in measures of maternal morbidity, except for a higher incidence of endomyometritis with failed trial of labor (13 versus 3%). The only consistent differences observed between successful and unsuccessful trials in all groups were length of hospitalization and rate of cervical dilatation in active labor (1.4 versus 0.5 cm/hour). CONCLUSION: Although each regional level II hospital successfully conducted trials of labor in patients with previous cesarean birth, there was considerable variation among sites regarding frequency of utilization, suggesting a strong influence of nonclinical patient-physician factors upon the decision-making process.

Cesarean Section↗
PubMed1992

Ascites: a portent of cardiopulmonary complications in the preeclamptic patient with the syndrome of hemolysis, elevated liver enzymes, and low platelets.

OBJECTIVE: Maternal ascites is frequently found at cesarean delivery in patients with severe preeclampsia or eclampsia expressed as hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome). We attempted to determine whether large-volume maternal ascites present at cesarean delivery in HELLP syndrome patients is correlated with disease severity or with any specific form of increased maternal morbidity. METHODS: For this retrospective case series, we reviewed the medical records of 190 patients and noted the presence or absence of large-volume maternal ascites, peripartum complications, laboratory data, and specific operative techniques. RESULTS: The incidence of large-volume ascites in patients with HELLP syndrome who underwent abdominal delivery was approximately 10% in classes 1, 2, and 3. Compared with HELLP syndrome patients without ascites, those with HELLP-associated ascites at surgery had a significant sixfold increase in the incidence of congestive heart failure and a ninefold increase in the incidence of adult respiratory distress syndrome, both of which usually became clinically apparent within 24 hours postpartum. Those HELLP syndrome patients without ascites at surgery developed congestive heart failure or adult respiratory distress syndrome infrequently, and more than 24 hours postoperatively. CONCLUSION: Cautious fluid administration and observation for cardiopulmonary deterioration are crucial in management of the critically ill, high-risk group of HELLP syndrome patients with large-volume ascites.

Adult↗
PubMed1991

Administration of heparin by subcutaneous infusion with a programmable pump.

Heparin has a short half-life (8 to 12 hours) and therefore must be administered by continuous infusion or by intermittent subcutaneous injection. Intermittent subcutaneous injection may lead to fluctuation in the levels of anticoagulation attained. In correcting this deficiency, the programmable automated subcutaneous infusion pump in conjunction with weekly home nursing visits has been used. Eight pregnant women with documented deep venous thrombosis or embolic events before pregnancy who received such therapy were studied. Eight similar subjects who received intermittent subcutaneous injection, matched for age, parity, site of deep venous thrombosis, and days on a regimen of heparin therapy, served as the control group. The mean daily dose of heparin by subcutaneous infusion pump was higher (29,445 vs 13,822 U), resulting in smoother, more therapeutic heparinization (mean partial thromboplastin time, 20.6 vs 10.4 seconds above control) when compared with the intermittent subcutaneous injection group (p less than 0.05, p less than 0.007). There were two complications (hematoma, site infection) in the intermittent subcutaneous injection group while none occurred in the subcutaneous infusion pump group. When used in concert with weekly home visits, the subcutaneous infusion pump method of administration allowed more even control of anticoagulation, appeared to result in fewer complications (although not statistically significant), and subjectively was better received by patients than the intermittent subcutaneous injection technique.

Adult↗
PubMed1991

The natural history of HELLP syndrome: patterns of disease progression and regression.

Despite much recent interest in HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count), there is little published information about the natural history of this unique form of severe preeclampsia-eclampsia. The time course and pattern of laboratory abnormalities for 158 patients with HELLP syndrome managed in a single tertiary referral center between 1980 and 1989 were studied retrospectively. Despite considerable patient variation, most gravid women with HELLP syndrome had decreasing platelet counts until 24 to 48 hours after delivery. Conversely, lactate dehydrogenase concentrations usually peaked 24 to 48 hours post partum. In all patients who recovered, a platelet count greater than 1,000,000/mm3 was spontaneously achieved by the sixth postpartum day or within 72 hours of platelet nadir. An upward trend in platelet count and a downward trend in lactate dehydrogenase concentrations should be apparent in patients without complications by the fourth postpartum day. These data provide baseline information against which the course of individual patients can be compared and the infrequent, atypical case identified for interventive therapy.

Analysis of Variance↗
PubMed1991

Left ventricular ejection fraction: single-plane and multiplanar transesophageal echocardiography versus equilibrium gated-pool scintigraphy.

The relative accuracy and precision of estimating left ventricular ejection fraction (EF) in dogs were assessed by two-dimensional transesophageal echocardiography (2D-TEE) and by three-dimensional transesophageal echocardiographic (3D-TEE) imaging and reconstruction. This assessment was accomplished by comparing each echocardiographic method to a gated equilibrium blood pool radionuclide (RN) standard. By using both correlation and regression analysis, 2D-TEE performed reasonably well in estimating RNEF (correlation coefficient [r] = 0.80, slope = 1.01, intercept = 6.37, standard error of the estimate [SEE], 8.98), but not as well as 3D-TEE (r = 0.86, slope = 0.83, intercept = 3.38, SEE, 5.74). Using Altman and Bland's methods of comparison analysis, it was found that 2D-TEE overestimated RNEF by 7% (standard deviation [SD], 8.8). This degree of overestimation was not consistent across the range of measurement. In contrast, 3D-TEE slightly underestimated RNEF by less than 3% and showed less variability (SD, 6.0). The accuracy of the 3D-TEE determinations was not dependent on the magnitude of EF. Additionally, a significantly higher proportion of the 2D-TEE measurements (0.30) compared with the 3D-TEE measurements (0.10) differed from RN values by more than 10% (P = 0.009, McNemar's test). At the clinically important low end of the EF range (RNEF less than or equal to 35%), 2D-TEE may be expected (with 95% confidence) to be within -15% to +28% EF of reference values, whereas 3D-TEE can be expected to be within -8% to +5% EF relative to RN.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Eosinophilic fasciitis associated with use of L-tryptophan: a case-control study and comparison of clinical and histopathologic features.

We investigated the relationship between use of L-tryptophan and development of eosinophilic fasciitis by two methods: a retrospective patient survey and a case-control study of patients with eosinophilic fasciitis diagnosed at the Mayo Clinic between 1977 and 1989. Before 1986, no traceable patients with eosinophilic fasciitis had taken L-tryptophan. Between Jan. 1, 1986, and July 31, 1989, 8 of 34 patients had ingested L-tryptophan (P less than 0.001). In the case-control study, traceable patients with eosinophilic fasciitis were matched with patients who had systemic sclerosis or rheumatoid arthritis and healthy control subjects who had undergone a general medical examination. Of the 60 matched control subjects, 2 had used L-tryptophan. Thus, the odds ratio was 19, indicating a 19-fold greater likelihood of use of L-tryptophan in patients with eosinophilic fasciitis than in the control group. A retrospective assessment of clinical features, response to treatment, and blinded review of biopsy specimens of skin and fascia in patients who had eosinophilic fasciitis with or without exposure to L-tryptophan disclosed no significant differences in the two groups. This retrospective study confirms a strong association between consumption of L-tryptophan and development of eosinophilic fasciitis in some patients. No clinical or histopathologic features were detected that distinguished this disorder on the basis of previous exposure to L-tryptophan.

Adult↗
PubMed1991

Acute gestational pyelonephritis: the impact on colloid osmotic pressure, plasma fibronectin, and arterial oxygen saturation.

Acute gestational pyelonephritis infrequently leads to nonhydrostatic permeability pulmonary edema known clinically as acute respiratory distress syndrome (ARDS). In this form of ARDS, sepsis is considered the primary cause of pulmonary dysfunction. Decreases in colloid osmotic pressure, plasma fibronectin, and arterial oxygen saturation are associated with a worsening prognosis in septic conditions. We sought to investigate the changes in these parameters with acute gestational pyelonephritis to gain insight into the factors that may place the patient at risk for sepsis-related morbidity. Colloid osmotic pressure, plasma fibronectin, and arterial oxygen saturation via pulse oximetry were prospectively measured during the inpatient treatment of 17 pregnant patients with acute gestational pyelonephritis. All three parameters achieved their nadir within 24 hours of hospitalization and the initiation of therapy. Although no patient developed significant pulmonary dysfunction, we believe that patient susceptibility for pulmonary edema and general morbidity could be maximal in the first 24 hours after therapy. Future studies using a larger number of patients may identify one or more of these laboratory parameters as helpful in identifying gravid patients who are at risk of developing gestational ARDS.

Acute Disease↗
PubMed1991

Cordocentesis (funipuncture) by maternal-fetal fellows: the learning curve.

One hundred cordocenteses were attempted at the University of Mississippi Medical Center between July 1, 1989, and June 1, 1991. There were 1.3 attempts for each successful umbilical blood sampling. The overall success rate was 94%. The first-year fellows-in-training attempted 61 procedures with a 90.2% success rate within two attempts and an overall success rate of 95.1%. Second-year fellows attempted 32 procedures with a 93.8% success rate within two attempts and an overall success rate of 93.8%. Procedure-related complications included five episodes of fetal bradycardia (one resulting in a stillbirth at 20 weeks) and a single case of chorioamnionitis. Of the three perinatal deaths, two were associated with severe congenital anomalies resulting in a corrected procedure-related mortality rate of 1%. The morbidity and mortality associated with cordocentesis appears to be relatively low and fellows-in-training can perform such procedures with no apparent increase in complications if appropriately supervised.

Blood Specimen Collection↗
PubMed1991

Design of 20 MHz wideband piezoelectric transducers for close proximity imaging.

Quarter wave matching of ultrasonic transducers with two layers (glass and parylene) were studied with computer simulation. These layers are located between the piezoelectric transducer and the acoustic load. The purpose is to achieve a short impulse response and high efficiency broadband transfer in a practical manner for high frequency transducers. The acoustic impedances of these layers were chosen based on transmission line theory. A method to measure acoustic properties of the matching layers and a method to choose the material are discussed. The advantages in using a quarter wavelength of glass and parylene as the matching layers are given. The 6 dB fractional bandwidth of the simulated transmission-reception transfer was found to be 0.75, which is a factor of at least 6 improvement over a nonmatched transducer.

Computer Simulation↗
PubMed1990

The clinical spectrum of the eosinophilia-myalgia syndrome associated with L-tryptophan ingestion. Clinical features in 20 patients and aspects of pathophysiology.

We describe the clinical spectrum of the L-tryptophan-associated eosinophilia-myalgia syndrome in 20 patients. In all but one case, patients met the Centers for Disease Control (CDC) case definition for the syndrome: peripheral blood eosinophilia (eosinophil count greater than 1.0 x 10(9)/L) and generalized, disabling myalgias without other recognized causes. Three patients with eosinophilia and myalgia developed eosinophilic fasciitis, and 4 other patients developed, respectively, pneumonitis and myocarditis, neuropathy culminating in respiratory failure, encephalopathy, and fibrosis about the common bile duct. No relation was apparent between dose or duration of L-tryptophan exposure and the eosinophilia-myalgia syndrome. No organic contaminants were identified in L-tryptophan preparations taken by patients or asymptomatic users when these preparations were examined by chromatography or mass spectroscopy. Biopsy specimens in 12 patients showed a mononuclear exudate with a variable admixture of eosinophils in affected tissues, including skin, fascia, muscle, and some viscera. Eosinophil toxic granule proteins, major basic protein, and eosinophil-derived neurotoxin were elevated in the serum and urine of patients compared with normal control subjects (P less than 0.01 and P less than 0.02, respectively). Immunofluorescence showed major basic protein deposited outside of eosinophils in affected tissues, indicating that toxic granule proteins are released in diseased organs. Treatment included withdrawal of L-tryptophan in all cases. Corticosteroids were prescribed for 16 patients and diuretics alone for 1 patient; no drugs were prescribed for 3 patients. Four patients have recovered fully, others are stable or slowly recovering, and 1 is gravely ill despite prolonged treatment.

Adult↗
PubMed1990

Plasma exchange for preeclampsia. I. Postpartum use for persistently severe preeclampsia-eclampsia with HELLP syndrome.

The postpartum use of plasma exchange with fresh-frozen plasma was assessed in a group of seven women with severe preeclampsia-eclampsia and HELLP syndrome (hemolysis, elevated liver enzymes, and low platelet count) that persisted greater than 72 hours after delivery. During the study interval in which a total of 107 gravid women with HELLP syndrome were seen in our referral center, these seven patients (6.5%) demonstrated persistent thrombocytopenia (platelet count usually less than 30,000/mm3), rising lactic dehydrogenase (greater than 1000 IU/L) and evidence of multiorgan dysfunction. The seven case histories emphasize the variety of clinical and laboratory profiles that can be encountered in this small group of gravid women at risk for severe morbidity or mortality. Up to three 3 L plasma exchanges were required to effect permanent disease arrest and reversal. Utilization of the IBM 2997 Cell Separator system permitted bedside performance of procedures with enhanced convenience and optimal medical management. Successful plasma exchange was associated with (1) sustained increases in the mean platelet count at 24, 48, and 72 hours that were 2.2, 3.6, and 4.5 times the preexchange platelet counts and (2) a decreasing trend in lactic dehydrogenase concentrations below 1000 IU/L within 48 hours of exchange plasmapheresis. The current series of patients supports our recommendation that a trial of plasma exchange(s) with fresh-frozen plasma be considered for treatment of the infrequent postpartum case of HELLP syndrome that fails to abate within 72 hours of delivery and in which other evidence develops of an ongoing, widespread, and life-threatening thrombotic microangiopathy.

Adolescent↗