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Biomedical subjects

M J Roberts

Publications and source records attributed to M J Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1998

Distribution and excretion of venlafaxine and O-desmethylvenlafaxine in human milk.

AIMS: To characterise the transfer of venlafaxine (V) and its O-desmethyl metabolite (ODV) into human milk by measuring milk/plasma (M/P) ratio, and to estimate the likely dose received by a breast-fed infant. METHODS: Milk and plasma samples were collected from three lactating women who were taking venlafaxine for depression, and were at steady-state. In two of the patients, venous blood and milk samples were collected 0, 1, 2, 3, 4, 6, 8 and 12 h post dose, while in the third patient a single pair of blood and milk samples was obtained 0.83 h post dose. A plasma sample was obtained from each of their infants. V and ODV were measured in plasma and milk by high performance liquid chromatography. M/P was calculated and infant dose estimated as drug concentration in milk x a milk intake of 0.15 l kg(-1) day(-1), relative to the weight-adjusted maternal dose. RESULTS: Mean M/P for V was 4.1 (range 2.8-4.8) and 3.1 for ODV (range 2.8-3.8). The mean total infant dose (as V equivalents) was 7.6% (range 4.7-9.2%) of the maternal weight-adjusted dose, with approximately equal amounts of V (3.5%) and ODV (4.1%) in the dose. ODV (median 100 microg I(-1)) was detected in the plasma of all three infants. The infants were healthy and showed no acute adverse effects. CONCLUSIONS: These preliminary data show that the total dose of V and ODV ingested by breast-fed infants can be as high as 9.2% of maternal intake. Moreover there were measurable concentrations of ODV in the infants' plasma. We recommend that exposed infants should be observed closely.

Adult↗
PubMed1998

Comparison of carprofen and pethidine as postoperative analgesics in the cat.

The postoperative analgesia and sedation in cats given carprofen (4.0 mg/kg bodyweight by subcutaneous injection preoperatively) was compared to that in cats given pethidine (3.3 mg/kg bodyweight by intramuscular injection postoperatively) in a controlled, randomised, blinded, multicentre clinical trial. Further dosing with the particular analgesic was allowed if a cat was exhibiting unacceptable pain. In total, 57 carprofen cases and 59 pethidine cases were evaluated. Significantly fewer cats in the carprofen group required additional doses of analgesic, and mean pain scores were significantly lower from four hours after ovariohysterectomy, and at 18 to 24 hours after castration, compared to the pethidine group. In conclusion, carprofen provided as good a level of postoperative analgesia as pethidine, but of a longer duration (at least 24 hours) and was well tolerated. It thus provides an option for 'pre-emptive analgesia' in cats about to undergo surgery.

Analgesics, Opioid↗
PubMed1997

What influences patients' reports of three aspects of hospital services?

OBJECTIVES: Market forces make it essential to know what policies and actions influence patients' reports of hospital services. No studies have examined the role of patient characteristics, labor quality and staff characteristics, nonlabor resources, managerial practices, and employee attitudes within a single investigation. METHODS: The authors collected, simultaneously, data about labor, management and service processes, nonlabor resources, and employee attitudes on 117 nonintensive medical-surgical inpatient units in 17 hospitals selected from a pool of 69 institutions within a metropolitan area by a stratified random sample. Of the 2,595 patients who agreed to participate, 2,051 (79%) completed telephone interviews regarding their experiences with physical care, education, and pain management services within 26 days of hospital discharge. RESULTS: A significant amount of variation in patients' service reports was explained (adjusted R2 = 0.41 physical care, 0.35 pain management, 0.44 education). Although the predictors varied for each service report, patient characteristics, especially those related to personal resources, had a large explanatory role. A labor assignment pattern that could explain why earlier studies found labor quality and staff characteristics to have only a weak role in the prediction of patients' service reports was noted. CONCLUSIONS: The results related to patient characteristics may indicate opportunities to improve care by confronting service design strategies that erroneously rely on a homogeneous patient population. Measurement challenges identified by this study must be addressed to determine the role of labor quantity and staff characteristics.

Health Care Surveys↗
PubMed1997

Choreography of the squid's "nuptial dance".

A mass spawning of squid resembles, at first glance, a chaotic "nuptial dance" (1). But for the first time, we have applied 3-D, radio-linked acoustic positioning (RAP) to this confusing process, and our early results now reveal a choreography that is, in fact, well organized in time and space. Remote tracking with RAP of individual Loligo vulgaris reynaudii off South Africa has provided insights into the daily sequence of behaviours that lead these animals to aggregate for sexual selection. Each dawn, the squid navigate for several kilometers, towards the shore, to small, well-defined zones near egg beds on the substrate. After several hours of circling above the egg beds, a pelagic, 3-D lek-like aggregation of large males forms: females are drawn in, and the aggregation condenses as the females and males pair, mate, and lay eggs. Smaller "sneaker males" remain on the periphery of the mating arena and, from this station, attempt extra-pair copulations (EPCs). The mating system of squids is thus unexpectedly complex, rivaling those of mammals and birds (2, 3). Commercial squid-jigging fishermen in South Africa have recently been attracted to the spawning grounds, and they have been successful. Moreover, their activities may be selective for large males. Thus, attention should be devoted to ensuring that such targeted fishing does not alter the characteristics of squid population genetics. Remote tracking and video observations, in combination with genetic analyses, may offer a new opportunity to monitor mating effort and reproductive success, and thus to manage the fishery.

Animals↗
PubMed1995

2,000 patients relate their hospital experiences.

This paper uses the reports of more than 2,000 adult medical/surgical patients drawn from 17 randomly selected hospitals within a midwestern major metropolitan area to (1) describe the differences between patients' reports and ratings of car, (2) determine the influence of service failures on patients' recommendations of a hospital to family and friends and (3) suggest constructive managerial responses to current patient satisfaction monitoring strategies.

Adult↗
PubMed1994

Efficacy of 100 mg of double-bolus alteplase in achieving complete perfusion in the treatment of acute myocardial infarction.

OBJECTIVES: The purpose of this study was to assess the efficacy of 150 mg of aspirin plus 100 mg of alteplase, administered as two intravenous bolus injections of 50 mg each given 30 min apart, and followed by intravenous heparin, on infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade 3). BACKGROUND: Previous workers have shown in animals that reducing the duration of an infusion of recombinant tissue-type plasminogen activator increases the initial rate of thrombolysis, resulting in high early infarct-related coronary artery patency rates. The logical progression of this idea is bolus administration. METHODS: Consecutive patients presenting up to 6 h from the onset of symptoms were recruited for the study. Angiography was performed at 60 and 90 min after the first bolus and between 19 to 48 h after study entry. Patients were followed up for 1 month. RESULTS: At 60 min, angiography revealed infarct-related coronary artery patency of TIMI flow grade 3 in 55 (86%) of 64 patients (95% confidence interval [CI] 75% to 93%) and TIMI flow grade 2 or 3 in 58 (91%) of 64 patients (95% CI 81% to 97%). At 90 min, infarct-related artery patency of TIMI flow grade 3 was achieved in 74 (88%) of 84 patients (95% CI 79% to 94%) and TIMI flow grade 2 or 3 in 78 (93%) of 84 patients (95% CI 85% to 97%). Two patients (2.4%) had early angiographic reocclusion whereas 10 (11.9%) had late reinfarction. Bleeding episodes were mostly minor, and there was no cerebrovascular bleeding. Five patients (6.0%) died within 1 month of the acute myocardial infarction. CONCLUSIONS: In 84 patients with acute myocardial infarction, administration of 100 mg of double-bolus (2 x 50 mg) alteplase, aspirin and heparin is associated with remarkably high early infarct-related coronary artery patency rates (TIMI flow grade 3) of 86% and 88%, respectively, at 60 and 90 min.

Adult↗
PubMed1994

Time delays to lytic therapy and outcome in 100 consecutive patients with a history suggestive of acute myocardial infarction in an area with access to a mobile coronary care unit.

Time delays to fibrinolytic treatment and outcome were assessed in 100 consecutive patients, with suggestive symptoms and electrocardiographic changes of acute myocardial infarction, admitted to the coronary care unit of this hospital. All patients admitted from out-of-hospital had access to a mobile coronary care unit. Initially, 40 patients called a general practitioner, 30 called the '999' operator, 12 called the mobile coronary care unit, 10 reported directly to the Accident and Emergency Department, seven were in-hospital and one spoke to the general practitioner's receptionist. Subsequently, 59 patients were attended by the mobile coronary care unit, 34 were admitted via the Accident and Emergency Department and seven had symptoms in-hospital. Thrombolytic therapy was initiated in 45/59 (76%) patients by the mobile coronary care unit staff and in 29/34 (85%) patients in the Accident and Emergency Department by cardiac staff. The remaining 26 patients received thrombolytic treatment in the hospital coronary care unit or cardiac department. The mean (+/- SEM) time from symptom onset to the initiation of thrombolytic therapy was 127 (+/- 11 min) for those patients treated by the mobile coronary care unit staff and for those treated in the Accident and Emergency Department was 187 (+/- 13 min) (P = 0.005). Multiple regression analysis showed significant reductions in total time delay if patients received thrombolytic therapy by the mobile coronary care unit staff out-of-hospital, when chest pain began in-hospital, or if patients had a previous myocardial infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Ambulances↗
PubMed1994

Acute mountain sickness -- experience on the roof of Africa expedition and military implications.

Acute Mountain Sickness (AMS) is a potentially severe problem for military exercises and operations and may present in a variety of ways as was the case on the "Roof of Africa" Expedition 1990. Four cases are described and the pathophysiology of AMS is discussed. Gradual acclimatization to increasing altitude will decrease the incidence of AMS, but pharmacological prophylaxis is recommended when time is short, acetazolamide being the drug of choice.

Acclimatization↗
PubMed1993

Double-blind randomized trial of alteplase versus placebo in patients with chest pain at rest.

Patients who have chest pain occurring at rest are at a significant risk of myocardial infarction and or sudden death. Most trials enter patients with anginal rest pain after an initial screening period. Thus, the clinical efficacy of early thrombolytic treatment for patients with rest pain remains unproven. Eighty patients with chest pain at rest and with ECG changes of ST depression of at least 1 mm in any ECG lead, were randomized to alteplase 100 mg infused over 3 h, or placebo. Concomitantly, all patients received intravenous heparin and 300 mg of aspirin daily (unless contra-indicated). Seventy-four patients had coronary angiography (the majority within 72 h of admission) of which 73 were assessable. The patency of the ischaemia-related vessel was not significantly greater in the alteplase treated group (81% vs 78%, P = 0.82). The culprit lesion morphology tended to be more concentric in the alteplase treated group (84% vs 56%, P = 0.06) although alteplase treatment was not associated with a significant reduction in the severity of the culprit lesion stenosis. Intra-coronary thrombi were detected in 7% of patients (3% placebo, 11% alteplase, P = 0.35). The mean left ventricular ejection fraction or the alteplase-treated group was 49 +/- 3% and for the placebo-treated patients 56 +/- 3% (P = 0.05). There was no difference in the total in-hospital cardiac event rate i.e. cardiac death, myocardial infarction and coronary revascularization between patients receiving alteplase (10%, 63%, and 38%) and those receiving placebo (8%, 65%, and 30%) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Excretion of lignocaine and its metabolite monoethylglycinexylidide in breast milk following its use in a dental procedure. A case report.

The excretion of lignocaine in breast milk has been documented in a 34-year-old woman following the injection of 20 mg lignocaine for a dental alloy restoration in the right upper quadrant. Lignocaine and its primary metabolite monoethylglycinexylidide in milk and plasma were quantified by high-performance liquid chromatography. The concentration of lignocaine in milk ranged from 44-66 micrograms l-1 while that for monoethylglycinexylidide ranged from 35-41 micrograms l-1. The milk: plasma ratios for lignocaine and monoethylglycinexylidide were 1.1 and 1.8, respectively. The calculated daily infant doses for the parent drug and metabolite were both less than 0.01 mg kg-1 day-1. With the exception of very rare allergic reactions, these levels of infant exposure are extremely low and of no toxicological significance. Nursing mothers receiving lignocaine for standard dental procedures can be advised that continuation of breast feeding is safe.

Adult↗
PubMed1992

DNA polymorphisms of the human CD46 gene in fetal and adult tissues.

DNA polymorphisms of the CD46 gene were investigated using a full length cDNA probe and five different restriction enzymes in genomic DNA samples from human fetal tissues and adult peripheral blood leukocytes. A HindIII polymorphism was observed and was classed as Types I, II and III at a ratio of approximately 3.5:2:1, depending on the presence or absence of two polymorphic fragments of 4.5 and 2.0 kb. No variation of polymorphic distribution was evident between the fetal and adult samples. Whether variation in CD46 expression between maternal and fetal tissue is relevant to fetal viability in pregnancy remains to be established.

Adult↗
PubMed1992

Cancer presentation in the emergency department: a failure of primary care.

Emergency departments are intended to be the location of entry into the health care system for patients with acute problems, such as injuries and myocardial infarctions. In contrast, cancer should optimally be detected during periodic health examinations, either through screening procedures or by early detection from signs and symptoms which prompt a routine visit to a primary care physician. This study was undertaken to describe patients who present to an emergency department with urgent symptoms and signs, are hospitalized, and subsequently diagnosed with cancer (ED group). One hundred twenty-nine patients were retrospectively studied. When compared with patients diagnosed in a primary care setting (tumor registry patients), the ED group was significantly older, more often male, had a significantly lower survival rate, and more frequent metastatic disease at diagnosis (P less than .001). The ED group accounted for 5.3% of the new tumor registry patients for the study years. Only 3.1% of the ED group had no insurance, and 21% reported no personal physician. Strategies are needed for patients and physicians to reduce the number of late-diagnosed cancer cases presenting in emergency departments.

Aged↗
PubMed1992

The excretion of dothiepin and its primary metabolites in breast milk.

1. The excretion of dothiepin, nordothiepin, dothiepin-S-oxide and nordothiepin-S-oxide into breast milk was studied in eight women. Exposure to drug was measured in five of their infants, and possible drug-related effects were assessed in all eight infants. 2. Using pre-feed milk samples mean (+/- s.e. mean) milk:plasma (M:P) ratios were 0.78 +/- 0.12, 0.85 +/- 0.16, 1.18 +/- 0.29 and 1.86 +/- 0.29 for dothiepin, nordothiepin, dothiepin-S-oxide and nordothiepin-S-oxide, respectively. In post-feed milk samples, the mean M:P ratio for dothiepin (1.59 +/- 0.32) was significantly greater (P less than 0.05) but M:P ratios for the metabolites were similar. 3. Mean total calculated infant daily doses, (in dothiepin equivalents and as a percent of the maternal dose) were 0.58% for dothiepin, 0.23% for nordothiepin, 2.47% for dothiepin-S-oxide, and 1.17% for nordothiepin-S-oxide. 4. Plasma samples were obtained from five infants. In one, both dothiepin and nordothiepin were below their minimum quantifiable levels (2 micrograms l-1) while in four others both dothiepin-S-oxide and nordothiepin-S-oxide were below their minimum quantifiable levels (10 micrograms l-1). No adverse effects were found in any of the eight infants. 5. Use of dothiepin by depressed mothers is unlikely to be a significant hazard to their breast-feeding infants.

Adult↗
PubMed1992

Visual and profilometric wear measurements.

Wear of composites can be estimated by the degree of marginal discrepancy between the prepared cavity wall and the occlusal margins of composites. Such evaluations are done on casts by comparing and rating the marginal discrepancy with those on standard casts. We analyzed the reliability of this technique on metal and stone specimens. These specimens contained grooves of different width and depth. For the visual comparison we used stone casts of machined standards of known groove depth. We measured the depths of the metal specimens with a profilometer and made stone casts of these original specimens. Using the stone casts of the standards, five dentists estimated the unknown groove depths on the remaining stone casts. These estimates were done under standardized conditions and repeated by each dentist on five different occasions. The results showed that visual depth evaluations of die stone specimens underestimated the depths when compared with the values measured with a profilometer on the original metal models. One investigator gave significantly different (p less than 0.05) groove depth estimates at different occasions.

Calcium Sulfate↗
PubMed1991

Effectiveness of double bolus alteplase in the treatment of acute myocardial infarction.

Fifty-nine consecutive patients presenting within 6 hours of the onset of symptoms of an acute myocardial infarction were treated with 150 mg of soluble aspirin orally, and either 70 or 100 mg of alteplase divided into 2 intravenous bolus injections separated by 30 minutes. Dosage regimens were either 20 followed by 50 mg (group A), 50 followed by 20 mg (group B), or 50 followed by 50 mg (group C). Coronary angiography 60 minutes after the first bolus showed infarct-related coronary artery patency (Thrombolysis in Myocardial Infarction score 2 or 3) in 13 of 16 (81%) patients in group A, 12 of 17 (71%) in group B, and 10 of 11 (91%) in group C (overall patency rate at 60 minutes: 35 of 44 [80%] patients; 95% confidence interval 68 to 91%). At 90 minutes, patency rates were 15 of 20 (75%) patients in both groups A and B, and 18 of 19 (95%) in group C (overall patency rate 48 of 59 [81%] patients; 95% confidence interval 72 to 91%). Residual thrombus was identified with the 90-minute angiogram in 7 patients in group A, 5 in group B, and 3 in group C. Although there was no statistically significant difference in patency between the 3 dosage regimens at either 60 or 90 minutes there was a trend toward increased patency and more complete thrombolysis at 90 minutes in group C. No episodes of bradyarrhythmia, hypotension or cerebrovascular bleeding were observed after double bolus therapy. There were 7 episodes (12%) of reocclusion, and 3 deaths (5%) within 1-month follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

A cellular transtelephonic defibrillator for management of cardiac arrest outside the hospital.

A cellular transtelephonic defibrillator facilitates early defibrillation in remote areas and involves electrocardiographic diagnosis and defibrillation control by a physician remote from but in voice contact with the patient-unit operator. The patient unit contains a microprocessor, microphone, defibrillator, electrocardiogram/defibrillator electrode pads and cellular telephone. Activation of the patient-unit initiates automatic dialing and contact with the remotely sited base station within 35 to 50 seconds. The physician at the base station identifies the rhythm and controls defibrillator charging and discharge. The minimal interaction required between the system and the local operator makes it suitable for use by minimally trained first responders. The cellular transtelephonic defibrillator has been tested in 211 calls responded to by a physician-manned mobile coronary care unit over distances up to 15 miles in an urban area. Satisfactory electrocardiographic transmission and voice communication were established in 172 of 211 calls (81.5%). In 39 (18.5%), connection with the base station either could not be established or maintained mainly because of geographic location or battery failure. One hundred direct current shocks of 50 to 360 J were effectively administered to 22 patients with 48 episodes of ventricular fibrillation or ventricular tachycardia with successful correction of 46 of 48 episodes using 1 to 4 shocks per episode. Widespread distribution of such devices could improve survival in patients with cardiac arrest outside the hospital.

Ambulances↗
PubMed1991

Genetic epidemiology of Down's syndrome in Shetland.

Pedigrees of all known cases, on Shetland, of Down's syndrome, cytogenetically confirmed as trisomy 21, and of a control for each patient matched by birth date, sex and birth place, were traced over a minimum of eight generations. Mean kinship coefficients in all pairs of Down's syndrome patients and in all pairs of controls were similar. The kinship between the father and mother of each case shows that the parents are more closely related than the general level of relationship in the population, suggesting some recessive element in the etiology. It is argued that the effect of the resulting increased homozygosity would be to prevent the loss of the conceptus that occurs in the majority of trisomy 21 conceptions.

Adult↗