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Biomedical subjects

M Irwin

Publications and source records attributed to M Irwin.

At least 55 records · Page 3Linked to original sources
PubMed1996

Partial night sleep deprivation reduces natural killer and cellular immune responses in humans.

Prolonged and severe sleep deprivation is associated with alterations of natural and cellular immune function. To determine whether alterations of immune function also occur after even a modest loss of sleep, the effects of early-night partial sleep deprivation on circulating numbers of white blood cells, natural killer (NK) cell number and cytotoxicity, lymphokine-activated killer (LAK) cell number and activity, and stimulated interleukin-2 (IL-2) production were studied in 42 medically and psychiatrically healthy male volunteers. After a night of sleep deprivation between 10 P.M. and 3 A.M., a reduction of natural immune responses as measured by NK cell activity, NK activity per number of NK cells, LAK activity, and LAK activity per number of LAK precursors (CD16,56, CD25) was found. In addition, concanavalin A-stimulated IL-2 production was suppressed after sleep deprivation due to changes in both adherent and nonadherent cell populations. After a night of recovery sleep, NK activity returned to baseline levels and IL-2 production remained suppressed. These data implicate sleep in the modulation of immunity and demonstrate that even a modest disturbance of sleep produces a reduction of natural immune responses and T cell cytokine production.

Cell Adhesion↗
PubMed1996

Long-term survival of chosen atrial-based pacing modalities.

Atrial-based cardiac pacing modalities were chosen in 341 of 684 (50%) patients selected for permanent cardiac pacing at the Grey Nuns Community Health Center between 1989 and 1995. There were 183 males and 158 females. Mean age was 70 years (range 8-97 years). The indications for atrial-based pacing were: advanced atrioventricular (AV) block (n = 166) 49%; sick sinus syndrome (n = 153) 45%; hypersensitive carotid sinus syndrome (n = 11) 3%; neurocardiac syncope (n = 10) 2.9%; and hypertrophic cardiomyopathy (n = 1) 0.3%. Forty-eight patients had a known history of paroxysmal atrial arrhythmias. All patients had routine follow-up performed at 24 hours, 7 days, 6 weeks, 3 months, and then 6 biannually. Mean follow-up was 6.5 years (range 1 month to 12 years). Observed survival of the programmed atrial-based modality was compared to the original mode chosen at the time of implantation. Thirty-five of 37 (95%) chosen for AAIR modes remain programmed AAIR. Twenty-two of 24 (92%) chosen for VDDR modes remain programmed VDDR. Two hundred and fifty-five of 280 (91%) chosen for DDD or DDDR modes remain programmed DDDR. Two of 37 (5%) patients originally implanted with AAI pacing systems were upgraded to DDDR mode due to new onset AV block. One of 24 (4%) patients originally implanted with a VDDR pacing system was upgraded to DDDR due to loss of atrial sensing of the single pass lead. Twenty-six of 304 (8.5%) patients originally implanted with DDD/DDDR (n = 25) and VDDR (n = 1) pacing systems were reprogrammed to VVI or VVIR: 16 (62%) due to sustained refractory atrial arrhythmias; 5 (19%) due to atrial lead malfunction; and 5 (19%) due to reasons unrelated to the pacing system. With careful review of the patients' conduction disorder and appropriate selection of pacing modality, the observed survival of long-term atrial-based pacing remains at 92% when compared to the chosen modality at the time of implantation. Atrial-based pacing may be used to reduce the incidence of atrial dysrhythmia with careful programming of the base atrial pacing rates.

Adolescent↗
PubMed1996

Management of intracardiac device recalls: a consensus conference. Participants of the Consensus Conference. North American Society of Cardiac Pacing and Electrophysiology (NASPE)

The incidence of cardiac device recalls seems to be increasing, in part due to increasing complexity, but also due to greater public awareness and regulatory overview. Manufacturers are responsible for postmarket surveillance of their implanted products; evidence for poor performance is usually evaluated by a Physician Advisory Committee (PAC) and unacceptable failure rates or modes prompt the issuance of a recall. A Consensus Conference was held March 6, 1995, in Toronto, Ontario, to discuss the management of cardiac device recalls after the provincial Ministry of Health issued unique guidelines regarding a recent lead problem. Various stakeholders expressed their views and concerns: the federal regulatory body, the provincial Ministry of Health and hospital association, manufacturers, hospital legal counsel, patient and media advocates, and physicians from the United Kingdom, the United States, and Canada. Specific recommendations included: the establishment of a National (or regional) Pacemaker (device/lead) Registry interposed between the manufacturer and the federal authority; the creation of a Recall Task Force (RTF) to deal with specific problems distinct from the manufacturers' PAC; emphasis on patient responsibility for obtaining regular follow-up and maintaining contact by a pacemaker passport system as exists in Europe; and the fair assignment of costs involved in a recall with specific emphasis on appropriate compensation for physicians and clinic personnel.

Defibrillators, Implantable↗
PubMed1996

The efficacy, applicability and side-effects of postoperative intravenous patient-controlled morphine analgesia: an audit of 1233 Chinese patients.

We analyzed data from 1233 Chinese patients of a wide age range who received patient-controlled analgesia (PCA) intravenous morphine for postoperative pain relief, during the period of January 1992 to May 1995. The analgesic regimen was standardized as follows: PCA bolus 1 to 1.5 mg; lock-out interval 5 minutes; one-hour maximum dose 0.075 to 0.1 mg.kg-1 and background infusion 0 or 0.5 mg.h-1. Most patients underwent major surgery that was broadly subclassified according to the anatomical area involved. The median verbal numerical rating scales of pain (0 to 10) at rest and while coughing for the first, second and third 24 hours were 3.0/5.0, 1.5/4.0 and 0/3.0 respectively and the corresponding demand to delivery ratios were 2.8 +/- 2.9, 2.6 +/- 2.4 and 2.4 +/- 2.6. The overall morphine consumptions in 1004 of these Chinese patients were 27.5 +/- 16.8, 17.8 +/- 16.1 and 18.1 +/- 21.0 micrograms.kg-1.h-1 during the first 16, 17 to 41 and 42 to 66 postoperative hours respectively. These figures were the same as for Caucasian patients managed in the same institution. Morphine consumption was significant higher following thoracic, upper abdominal and spinal surgery. Also it was higher in patients younger than 65 years, males, cigarette smokers and those with ASA physical status I or II. The commonest side-effects were nausea (34.5%) and vomiting (18.2%). Bradypnoea and oxygen desaturation occurred in 0.5% and 1.6% respectively. All cases were promptly detected and managed with no adverse outcomes. Most patients were satisfied (76.7% ranked "good") with their postoperative analgesia. The commonest reasons for dissatisfaction were inadequate pain relief, nausea and reluctance to self-control analgesic administration. It is concluded that PCA with intravenous morphine is effective and safe as a routine postoperative technique for Chinese surgical patients.

Aged↗
PubMed1996

Management of intracardiac device recalls: a consensus conference.

The incidence of cardiac device recalls seems to be increasing, due in part to increasing complexity, but also to greater public awareness and regulatory overview. Manufacturers are responsible for postmarket surveillance of their implanted products; evidence for poor performance is usually evaluated by a physician advisory committee, and unacceptable failure rates or modes prompt the issuance of a recall. A consensus conference was held March 6, 1995 in Toronto, Ontario to discuss the management of cardiac device recalls after the provincial Ministry of Health issued unique guidelines regarding a recent lead problem. Various stakeholders expressed their views and concerns: the federal regulatory body, the provincial Ministry of Health and hospital association, manufacturers, hospital legal counsel, patient and media advocates and physicians from the United Kingdom, the United States and Canada. Specific recommendations included the establishment of a national (or regional) pacemaker (device/lead) registry interposed between the manufacturer and the federal authority; the creation of a recall task force to deal with specific problems distinct from the manufacturers' physician advisory committee; emphasis on patient responsibility for obtaining regular follow-up and maintaining contact by a pacemaker passport system as exists in Europe; and the fair assignment of costs involved in a recall with specific emphasis on appropriate compensation for physicians and clinic personnel.

Algorithms↗
PubMed1996

Comparison of central venous catheter dressings in bone marrow transplant recipients.

PURPOSE/OBJECTIVES: To determine the effect of two central venous catheter (CVC) dressing protocols on catheter-related infections in hospitalized patients with long-term tunneled catheters undergoing an autologous bone marrow transplant (BMT), to determine the prevalence of long-term CVC-related infections in this population, and to identify other factors in the study sample related to long-term CVC infection. DESIGN: Experimental. SETTING: BMT unit of a regional oncology center in a tertiary care hospital. SAMPLE: The sample consisted of 101 adult patients with cancer with long-term, tunneled CVCs inserted in the operating room on admission for autologous BMT. METHODS: Patients randomly were assigned to one of two dressing-change procedure groups. The control group received the current standard of care for patients receiving BMT--a dry, sterile gauze dressing (DSGD) changed every 24 hours. The experimental group received Opsite 3000TM (Smith + Nephew Ltd., Massilon, OH) transparent moisture vapor permeable dressings (MVPD) changed weekly. MAIN RESEARCH VARIABLES: CVC infection rates, frequency of IV tubing changes, immune status, duration of catheter use, occurrence and outcome of catheter occlusion, and use of a catheter for total parenteral nutrition. FINDINGS: Researchers determined the difference in CVC-related infections between the two groups and the impact of select variables on CVC-related infection. When all categories of CVC-related infection (i.e., suspected, sepsis, tunnel) were considered, no statistical difference was found in the likelihood of the groups remaining infection-free (p = 0.76) over time. CVC sepsis occurred in one patient in the DSGD group and five patients in the MVPD group; however, this difference was not statistically significant over time (p = 0.067). CONCLUSIONS: Development of CVC sepsis or tunnel infection in close proximity to the time of CVC surgical placement suggests that factors other than the assigned dressing were associated with the occurrence of CVC-related infection in three cases. Although the MVPD group required dressing changes more frequently than every seven days (as specified by the protocol) because of exit-site drainage and nonocclusiveness, transparent dressings were more cost-effective than daily gauze dressings in this population. IMPLICATIONS FOR NURSING PRACTICE: For adults undergoing autologous BMT, either DSGD or transparent CVC dressing can be used safely based on patient preference and skin tolerance to the dressing material.

Adult↗
PubMed1996

Evidence for localization of biologically active recombinant retroviral vector to lymph nodes in mice injected intramuscularly.

We have developed a novel gene transfer drug, HIV-IT(V), for the treatment of HIV infection in humans. HIV-IT(V) is a retroviral vector encoding the HIV-1 IIIB env and rev genes and a neomycin resistance marker gene (neor). We have recently reported that HIV-IT(V) administered intramuscularly to male mice localizes primarily to the site of injection. In this study, we have investigated more extensively the localization and biological activity of HIV-IT(V) administered intramuscularly to female mice. Consistent with our previous findings, retroviral DNA was detected by PCR at the site of injection. Retroviral DNA was also detected in proximal lymph nodes, a tissue not examined previously. Potential for drainage of vector particles to regional lymph nodes was indicated by experiments showing that intramuscular injection of fluorescein-labeled latex beads concentrated in the regional lymph nodes in mice. The localization of retroviral DNA to the injection site and regional lymph nodes may play a role in the induction of the HIV-specific CTL responses detected in splenocyte populations isolated from mice 21 days after injection with HIV-IT(V).

Animals↗
PubMed1995

Polygraphic sleep measures differentiate alcoholics and stimulant abusers during short-term abstinence.

We hypothesized that stimulant abusers would sleep more and have more rapid eye movement (REM) sleep than primary alcoholics during acute withdrawal (first 10 days drug free) but would have opposite patterns during subacute withdrawal (days 11-14 drug free). We compared polygraphic sleep patterns during acute withdrawal (days 3-10) for 7 stimulant abusers and 8 alcoholics and during subacute withdrawal (days 11-14) for 7 different stimulant abusers and 8 different alcoholics. For comparison purposes, a group of normal controls from our preexisting database were matched for age and gender. Two statistically significant interactions were found: consistent with our hypothesis, stimulant abusers showed greater total sleep (TST) and REM sleep during acute withdrawal than subacute withdrawal, compared with alcoholics. In contrast, alcoholics showed less TST and REM sleep during acute withdrawal than during subacute withdrawal. Our polygraphic sleep data support the hypothesis that physiological withdrawal differs in alcoholics compared with stimulant abusers. Different mechanisms may underlie withdrawal in these two substances.

Acute Disease↗
PubMed1995

Euthanasia.

Explore the source record for details and available documents.

Attitude of Health Personnel↗
PubMed1995

Collision metastasis of bladder and prostate carcinoma to a single pelvic lymph node.

Genitourinary organs are at greater risk for multiple primary malignant neoplasms because of the high incidence of these tumours as primaries among all other organs. We present a case of prostate and bladder carcinoma metastasized to a single pelvic lymph node, called a "collision" metastasis, in a patient with four primary tumours.

Adenocarcinoma↗
PubMed1995

Multicenter experience with a bipolar tined polyurethane ventricular lead.

A multicenter study was undertaken to determine the failure rate of a specific bipolar tined polyurethane ventricular pacing lead, the Medtronic 4004/4004M pacing lead. Seven centers in the United States and Canada implanted 586 Medtronic 4004/4004M pacing leads. The study was designed to determine the probability and clinical manifestations of lead failure. Only failures compatible with an insulation problem were included. The Kaplan-Meier estimate of the percentage of 4004/4004M lead failures within 4 years after implantation was 14.1% (95% confidence interval: 8.5%-19.3%). Failures were manifested as sensing abnormalities, failure to capture, early battery depletion, and significant decrease in measured impedance compared with previous impedance measurements. The observed rate of failure is unacceptable, and strong consideration should be given to replacing the 4004/4004M pacing lead in pacemaker dependent patients and closely monitoring nondependent patients.

Adolescent↗
PubMed1995

Compliance in amblyopia therapy: objective monitoring of occlusion.

AIM/BACKGROUND: This study aimed to determine the feasibility of objective compliance monitoring of amblyopia therapy in clinical research. Occlusion has been the mainstay of amblyopia therapy for over 250 years, yet it has never been subjected to rigorous evaluation. Treatment regimens range arbitrarily from a few minutes to most of the waking hours of the day. Compliance is problematic and as, hitherto, accurate objective monitoring has been impossible it is not known how much occlusion is required to effect an improvement in vision. METHODS: An occlusion dose monitor (ODM) has been developed. The ODM consists of a modified occlusion patch and a miniature battery driven datalogger which periodically monitors patch skin contact. The patch is a standard disposable item with two miniature electrocardiogram electrodes attached to its undersurface. The datalogger comprises a high speed static RAM and a clock driven address counter. Data are retrieved using an IBM PC/AT computer. Fifteen child amblyopes were randomly allocated unilateral occlusion of 1, 4, or 8 hours per day for 4 weeks. Owing to data loss, presumed because of accumulation and discharge of static electricity, an additional child was included in the 8 hour group. Outcome measures were objective (ODM) and subjective (diary) compliance with treatment, logMAR visual acuity, and contrast sensitivity. RESULTS: Objective monitoring of occlusion is technically feasible and clinically informative. CONCLUSION: Objective monitoring of occlusion has opened up new research opportunities which, it is hoped, will enable the dose-effect relation of occlusion therapy in the various types of amblyopia to be investigated objectively, and facilitate the design of effective therapeutic regimens.

Amblyopia↗
PubMed1995

Cognitive recovery with abstinence and its relationship to family history for alcoholism.

OBJECTIVE: The relationship between drinking relapse and family history for alcoholism to cognitive functioning was investigated in alcoholics who completed a 28-day inpatient treatment program. METHOD: The current study examined 144 primary alcoholics who completed a battery of cognitive tests on admission to treatment and at a 3-4 month follow-up visit. Participants were classified as either family history positive (FH+) (n = 86) or family history negative (FH-) (n = 58) based on information on alcohol dependence in first degree relatives. The subjects were further classified as drinkers (n = 56) or abstainers (n = 88) at follow-up, based upon information gathered about their drinking practices during the interval. RESULTS: There were no differences between the groups based on family history status at admission to treatment. Comparisons made at follow-up revealed that the abstainers' (both FH+ and FH-) performance improved. The FH+ drinkers' performance was worse than that of both the FH- drinkers and the FH+ abstainers at follow-up. The poor performance of the FH+ drinkers relative to the FH- drinkers was not attributable to differences in drinking consumption during the test-retest interval. CONCLUSIONS: These results suggest that alcoholics who maintain abstinence following treatment show improvement on cognitive testing at follow-up; both FH+ and FH- abstainers showed improvement, indicating that a positive family history of alcoholism does not impede recovery that occurs with abstinence. The most important finding, however, is that the FH+ drinkers show greater deterioration at follow-up compared to the other groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Sequential imputation for multilocus linkage analysis.

A Monte Carlo method called sequential imputation is proposed for multilocus likelihood computations. This method is most useful in mapping situations where the data consist of large pedigrees with substantial missing information and it is desirable to perform linkage analysis utilizing data from many polymorphic markers simultaneously. A pedigree example with 155 individuals, 9 loci, and 155,520 haplotypes is used for illustration.

Diabetes Mellitus, Type 2↗
PubMed1994

Adaptive functioning in children with attention-deficit hyperactivity disorder.

OBJECTIVE: To evaluate the utility of the Vineland Social Adaptive Scale (Vineland) in measuring social adaptive functioning in children with attention-deficit hyperactivity disorder (ADHD). DESIGN: Cross-sectional group comparison. SETTING: Multidisciplinary hyperactivity and learning problem clinic at a tertiary referral center in Chicago, Ill. PARTICIPANTS: One hundred four school-age children with ADHD. INTERVENTION: None. MEASUREMENTS/MAIN RESULTS: The Vineland was administered to the study population. Despite average full-scale IQ scores (mean [+/- SD], 101 +/- 6), the children with ADHD had Vineland standard scores in the borderline to low-average range (73 +/- 14). The discrepancy between the Vineland standard scores and the full-scale IQ scores increased with increasing age and IQ. CONCLUSIONS: Children with ADHD referred to a tertiary attention problem clinic displayed significant social adaptive dysfunctioning on the Vineland. The evaluation of children with ADHD should include assessment of adaptive skills, and treatment planning for children with ADHD should include the identification of social and adaptive deficiencies when therapeutic goals are established.

Adaptation, Psychological↗
PubMed1994

Increased pressure for rapid eye movement sleep at time of hospital admission predicts relapse in nondepressed patients with primary alcoholism at 3-month follow-up.

OBJECTIVE: To determine whether polygraphic sleep recordings, obtained at the time of admission to an inpatient alcohol treatment program, predict abstinence and relapse 3 months following hospital discharge in nondepressed patients with primary alcoholism. DESIGN: Two independent, consecutive cohorts of patients (group 1, n = 28; group 2, n = 17) underwent all-night polygraphic sleep recordings and other clinical evaluations during the first and fourth weeks of a 1-month inpatient treatment program within a Veteran Affairs Medical Center. They were reevaluated 3 months following discharge to the community. None were treated with disulfiram or other medications during or after hospitalization. PATIENTS: All subjects were male veterans with primary alcoholism and without significant preexisting, secondary, or comorbid diagnoses such as major medical problems, depression, antisocial personality, or drug addiction. OUTCOME MEASURES: Relapse was defined as any alcohol consumption between discharge from the hospital and 3-month follow-up. RESULTS: Ten (36%) of 28 patients in group 1 were Relapsers at 3-month follow-up. Relapsers in group 1 showed significantly shorter Rapid Eye Movement (REM) latency, increased Rapid Eye Movement percent (REM%), and increased REM Density during their admission sleep studies compared with Abstainers. To replicate these observations, group 2 was then studied as a validation sample. Six (35%) of 17 patients relapsed. As in group 1, Relapsers had significantly shorter REM latency and increased REM% compared with Abstainers; REM Density was not significantly different in the Relapsers as compared with Abstainers in group 2. Using a principal components analysis based on these three REM sleep measures to determine "REM pressure," three separate discriminant function analyses (DFAs) were calculated: one for each group and one for all patients (n = 45) together. The DFA from group 1 correctly classified 22 (78.6%) of the 28 patients in group 1 and 13 (76.5%) of the 17 patients in group 2 as Relapsers or Abstainers. The DFA from group 2 correctly classified 13 (76.5%) of the 17 patients in group 2 and 23 (82.1%) of the 28 patients in group 1. The DFA formed from both groups together correctly classified 36 (80%) of the 45 patients. When the REM sleep measures at hospital admission and discharge were compared, no statistically significant effect of time was observed. Abstinence and relapse were not consistently related to other clinical measures at the time of hospital admission such as age, duration and severity of alcoholism, marital status, employment, hepatic enzyme levels, cognitive performance, or depression ratings. CONCLUSION: Short REM latency, increased REM%, and, possibly, increased REM Density at the time of admission to a 1-month inpatient alcohol treatment program predict relapse in nondepressed patients with primary alcoholism by 3 months following hospital discharge.

Alcohol Drinking↗