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Biomedical subjects

K E Martin

Publications and source records attributed to K E Martin.

At least 19 recordsLinked to original sources
PubMed2005

Select Listeria monocytogenes subtypes commonly found in foods carry distinct nonsense mutations in inlA, leading to expression of truncated and secreted internalin A, and are associated with a reduced invasion phenotype for human intestinal epithelial cells.

The surface protein internalin A (InlA) contributes to the invasion of human intestinal epithelial cells by Listeria monocytogenes. Screening of L. monocytogenes strains isolated from human clinical cases (n=46), foods (n=118), and healthy animals (n=58) in the United States revealed mutations in inlA leading to premature stop codons (PMSCs) in L. monocytogenes ribotypes DUP-1052A and DUP-16635A (PMSC mutation type 1), DUP-1025A and DUP-1031A (PMSC mutation type 2), and DUP-1046B and DUP-1062A (PMSC mutation type 3). While all DUP-1046B, DUP-1062A, DUP-16635A, and DUP-1031A isolates (n=76) contained inlA PMSCs, ribotypes DUP-1052A and DUP-1025A (n=72) contained isolates with and without inlA PMSCs. Western immunoblotting showed that all three inlA PMSCs result in the production of truncated and secreted InlA. Searches of the Pathogen Tracker database, which contains subtype and source information for more than 5,000 L. monocytogenes isolates, revealed that the six ribotypes shown to contain isolates with inlA PMSCs were overall more commonly isolated from foods than from human listeriosis cases. L. monocytogenes strains carrying inlA PMSCs also showed significantly (P=0.0004) reduced invasion of Caco-2 cells compared to isolates with homologous 3' inlA sequences without PMSCs. Invasion assays with an isogenic PMSC mutant further supported the observation that inlA PMSCs lead to reduced invasion of Caco-2 cells. Our data show that specific L. monocytogenes subtypes which are common among U.S. food isolates but rare among human listeriosis isolates carry inlA mutations that are associated with, and possibly at least partially responsible for, an attenuated invasion phenotype.

Bacterial Proteins↗
PubMed2001

Variation in clinician recommendations for multiple injections during adoption of inactivated polio vaccine.

OBJECTIVES: To describe variation in clinician recommendations for multiple injections during the adoption of inactivated poliovirus vaccine (IPV) in 2 large health maintenance organizations (HMOs), and to test the hypothesis that variation in recommendations would be associated with variation in immunization coverage rates. DESIGN: Cross-sectional study based on a survey of clinician practices 1 year after IPV was recommended and computerized immunization data from these clinicians' patients. STUDY SETTINGS: Two large West Coast HMOs: Kaiser Permanente in Northern California and Group Health Cooperative of Puget Sound. OUTCOME MEASURES: Immunization status of 8-month-olds and 24-month-olds cared for by the clinicians during the study. RESULTS: More clinicians at Group Health (82%), where a central guideline was issued, had adopted the IPV/oral poliovirus vaccine (OPV) sequential schedule than at Kaiser (65%), where no central guideline was issued. Clinicians at both HMOs said that if multiple injections fell due at a visit and they elected to defer some vaccines, they would be most likely to defer the hepatitis B vaccine (HBV) for infants (40%). At Kaiser, IPV users were more likely than OPV users to recommend the first HBV at birth (64% vs 28%) or if they did not, to defer the third HBV to 8 months or later (62% vs 39%). In multivariate analyses, patients whose clinicians used IPV were as likely to be fully immunized at 8 months old as those whose clinicians used all OPV. At Kaiser, where there was variability in the maximum number of injections clinicians recommended at infant visits, providers who routinely recommended 3 or 4 injections at a visit had similar immunization coverage rates as those who recommended 1 or 2. At both HMOs, clinicians who strongly recommended all possible injections at a visit had higher immunization coverage rates at 8 months than those who offered parents the choice of deferring some vaccines to a subsequent visit (at Kaiser, odds ratio [OR]: 1.2; 95% confidence interval [CI]: 1.0-1.5; at Group Health, OR: 1.8; 95% CI: 1.1-2.8). CONCLUSIONS: Neither IPV adoption nor the use of multiple injections at infant visits were associated with reductions in immunization coverage. However, at the HMO without centralized immunization guidelines, IPV adoption was associated with changes in the timing of the first and third HBV. Clinical policymakers should continue to monitor practice variation as future vaccines are added to the infant immunization schedule.

Child, Preschool↗
PubMed2000

The hidden costs of infant vaccination.

Combination vaccines to minimize injections required for infant vaccination, and new vaccines with improved safety profiles, will pose increasingly complex choices for vaccine purchasers in the future. How much of a premium to pay for such vaccines might be determined by taking into account (1) the psychological burden of multiple injections during a single clinic visit, and the costs of any additional visits to minimize these, and (2) the medical, work-loss, and incidental costs of common vaccine-associated symptoms. This cross-sectional survey included randomly-selected parents of 1-8-month-old infants who received vaccines in a Northern California health maintenance organization (HMO) in 1997. Interviewers called parents 14 days after the infant's vaccination to administer a 10-minute closed-ended interview in English or Spanish. Parents were asked about infant symptoms after vaccination, their preferences regarding multiple injections and their (theoretical) willingness to pay to reduce the number of injections their infant would receive, or to avoid the adverse symptoms experienced. Among 1769 eligible infants, interviews were completed with parents of 1657 (93%). The psychological cost of multiple injections was estimated by the willingness of parents to pay a median of $25 to reduce injections from 4 to 3, $25 from 3 to 2, and $50 from 2 to 1. Vaccine-associated symptoms caused mean costs of $42 in medical utilization and $192 in work-loss among the families who experienced those events (Ns=62 and 35, respectively). When averaged among all 1657 study infants, vaccine-associated symptoms after the index vaccination visit resulted in $2.91 in medical utilization, $4.05 in work-loss, and $0.74 in direct nonmedical costs, yielding total financial costs of $7.70. Parents of infants who had vaccine-associated symptoms said they would have paid a median of $50 to avoid these symptoms. Fever and fussiness were associated in logistic regression analysis with a two-fold increase in the odds of medical utilization, and fever with more than a three-fold increase in work loss. We conclude that multiple injections during a single clinic visit entail psychological costs. The psychological costs of vaccine-associated symptoms, as measured by willingness-to-pay methods, are higher than those resulting from multiple injections. The financial costs of medical utilization and work-loss resulting from common vaccine-associated symptoms are non-negligible and should be incorporated in economic analyses.

Cross-Sectional Studies↗
PubMed2000

Nurse practitioners: a comparison of rural-urban practice patterns and willingness to serve in underserved areas.

PURPOSE: To determine nurse practitioners' (NPs) practice patterns and willingness to practice in underserved areas in both rural and urban settings in a largely rural state. DATA SOURCES: A census of all NPs holding a Pennsylvania license and providing addresses in Pennsylvania or one of the contiguous states was conducted in 1996. The ZIP codes of practice sites were matched with 1990 census data. CONCLUSIONS: Nurse practitioners in rural areas are more likely than their urban counterparts to provide primary care in primary care practice settings, they see more patients per week, and they are more likely to be the principal provider of care for a higher percentage of their patients. Experience with managed care contracts is greater for urban NPs as is their willingness to practice in urban underserved areas. Rural NPs were more willing to practice in rural underserved areas than their urban counterparts. IMPLICATIONS FOR PRACTICE: Access to primary care continues to be a concern in rural areas. The increasing market penetration of managed care and the deficit of primary care providers in rural environments may lead to increased opportunities for NPs in the rural health care delivery system.

Adult↗
PubMed2000

A rural-urban comparison of patterns of physician assistant practice.

Access to primary care continues to be a concern in rural areas. The deficit of primary care providers in rural environments has the potential to increase the role of physician assistants (PAs) in the system of rural health care delivery. Little is known about the conditions, sites, and patterns of practice of PAs and their distribution in Pennsylvania, the state with the largest rural population. To learn more about these providers in rural and urban settings and their willingness to practice in underserved areas, the author conducted a census of all PAs who hold a Pennsylvania license. Survey results revealed significant rural-urban differences in socioeconomic, demographic, and practice profile parameters. Providers in rural areas are more likely than urban counterparts to practice primary care in a primary care practice setting; see more patients per week; and are the principal provider of care for a higher percentage of their patients. Experience with managed care is greater for urban PAs. A rural PA is more likely than an urban PA to practice in an underserved area. For both rural and urban PAs who practice primary care, significant differences were noted in their willingness to practice in a rural underserved area, compared to PAs who do not practice primary care.

Data Collection↗
PubMed1999

Obstacle crossing in subjects with stroke.

OBJECTIVE: To study the ability of subjects with stroke to successfully step over an obstacle during ambulation. SETTING: A geriatric rehabilitation unit in a tertiary referral hospital. SUBJECTS: Twenty-four inpatients with stroke (median time poststroke 27 days, interquartile range 21 to 44.5 days) able to walk 10 m unassisted without walking aids; also, 22 healthy subjects. METHOD: Subjects were required to step over obstacles of various heights and widths, ranging from 1cm to 8cm. A fail was scored if the obstacle was contacted by either lower limb or if assistance or upper limb support was required. The choice of leading limb and the presence of visual deficits and neglect were also recorded in the stroke subjects. Subjects were tested on two occasions. RESULTS: Significantly more fails were recorded for stroke subjects, with 13 subjects failing at least once. No preference was shown for leading either with the affected or with the unaffected leg. Stroke subjects showed inconsistent performance over the two testing sessions. CONCLUSION: The ability to negotiate obstacles was compromised and inconsistent in stroke subjects undergoing inpatient rehabilitation. This suggests that gait safety in this population remains threatened.

Activities of Daily Living↗
PubMed1998

Clinical outcomes and maternal perceptions of an updated model of perinatal care.

BACKGROUND: Postpartum hospital stays seem likely to remain limited even under new laws which mandate that insurers cover 48-hour hospitalization after uncomplicated delivery. Clinicians, who are increasingly practicing in capitated arrangements, need better information to maximize clinical benefit to mothers and newborns using finite resources. OBJECTIVE AND INTERVENTIONS: This study's aim was to evaluate the clinical outcomes, patient perceptions, and costs of a revised model of perinatal care services. In this model, a new postpartum care center was established for routine follow-up of newborns within 48 hours after hospital discharge, educational efforts were shifted from the postpartum hospitalization to the prenatal period, and lactation consultant hours were increased. DESIGN AND PARTICIPANTS: Controlled, nonrandomized (double cohort) study that compared mothers and newborns with hospital stays of 48 hours or less during the Baseline Care (preintervention) study period (N = 344) with those under the Revised Care (postintervention) study period (N = 456). SETTING: The Hayward, California, medical center of Kaiser Permanente, a nonprofit health maintenance organization. DATA COLLECTION: Telephone interviews were attempted with all mothers 3 weeks after delivery. Data on rehospitalizations, emergency department (ED) and clinic visits, and costs during the first 14 postpartum days were collected from computerized databases and chart review. OUTCOME MEASURES: The combined clinical outcome was defined as any undesirable health event, including rehospitalization, an ED visit, or an urgent clinic visit by either the mother or newborn within the first 14 days postpartum, or breastfeeding discontinuation within the first 21 days postpartum. Maternal satisfaction and costs were also studied. RESULTS: Of 876 attempted interviews, 800 were completed (91%). Analyses were adjusted for age, race, education, parity, breastfeeding experience, and other relevant variables. Among the interviewed mother-newborn pairs, 45% in the Revised Care group experienced the combined clinical outcome, compared with 52% in the Baseline Care group. Newborns in the Revised Care group (29%) were significantly less likely to make urgent clinic visits during the first 14 days of life than those in the Baseline Care group (36%). There were no differences between groups in newborn ED visits or rehospitalizations, maternal clinical outcomes, or breastfeeding continuation. Mothers in the Revised Care group expressed higher satisfaction with the newborn's care, the amount of information they received about newborn care and breastfeeding, and the amount of help they received with breastfeeding. Planned hospital care, planned follow-up visits, and unplanned care costs decreased by $149 per delivery, while the new prenatal class and increased lactation consultant services cost $58 per delivery, for an estimated overall reduction in cost. CONCLUSIONS: We conclude that the revised model of perinatal care in this health maintenance organization medical center improved clinical outcomes and maternal satisfaction for low-risk mothers and newborns without increasing costs.

Adult↗
PubMed1997

Mosaic partial trisomy 17 due to a ring chromosome identified by fluorescence in situ hybridisation.

We report on a 3-year-old-girl with mosaic partial trisomy 17 due to an additional ring chromosome 17 in 13% of cells analysed. This was identified by fluorescence in situ hybridisation (FISH) using a whole chromosome 17 specific paint as well as probes specific for the Smith-Magenis and Miller-Dieker regions of chromosome 17p. This girl showed mild developmental delay with subtle facial and other minor abnormalities including single palmar creases, generalised joint laxity, and a scoliosis.

Charcot-Marie-Tooth Disease↗
PubMed1997

Outpatient management practices associated with reduced risk of pediatric asthma hospitalization and emergency department visits.

OBJECTIVES: Effective outpatient care is believed to prevent hospitalization and emergency department (ED) visits resulting from childhood asthma. The aim of this study was to suggest priority areas for intervention by identifying outpatient management practices associated with the risk of these adverse outcomes in a large population. METHODS: This case-control study included children aged 0 to 14 years with asthma who were members of a regional health maintenance organization. Cases were children undergoing either a hospitalization or an ED visit for asthma during the study period. Control subjects were children with asthma without a hospitalization or an ED visit during the study period who were matched to patients on age, gender, and number of asthma-related hospitalizations in the past 24 months. Data on provider and parent asthma management practices were collected using chart review, closed-ended telephone interviews with parents, and computerized use databases. Multivariate analyses were conducted using conditional logistic regression models. RESULTS: Data were collected on 508 cases and 990 control subjects. A total of 43% of cases were reported by their parents to have moderately severe or severe asthma, compared with 20% of control subjects. Parents of cases with hospitalization were less likely than control subjects to have a written asthma management plan (44% vs 51%) and to report washing bedsheets in hot water at least twice a month (77% vs 86%). Cases with hospitalization were more likely to have a nebulizer (74% vs 56%). In the final multivariate model, race/ethnicity was not associated with having had either a hospitalization or an ED visit, as was lower socioeconomic status. Having a written asthma management plan [odds ratio (OR): 0.54; 95% confidence interval (CI): 0.30, 0.99] and washing bedsheets in hot water at least twice a month (OR: 0.45; 95% CI: 0.21, 0.94) were associated with reduced odds of hospitalization. Having a written asthma management plan (OR: 0.45; 95% CI: 0.27, 0.76) and starting or increasing medications at the onset of a cold or flu were associated with reduced odds of making an ED visit. CONCLUSIONS: Practices that support early intervention for asthma flare-ups by parents at home, particularly written management plans, are strongly associated with reduced risk of adverse outcomes among children with asthma.

Adolescent↗
PubMed1996

An assessment of practice support and continuing medical education needs of rural Pennsylvania family physicians.

Family physicians provide the greatest proportion of care in rural communities. Yet, the number of physicians choosing family practice and rural practice has continued to decline. Undesirable aspects of rural practice, such as professional isolation and a lack of or inadequate resources, are assumed to be associated with this decline. This article reports on the practice support and continuing medical education needs of rural family physicians. A mail survey was conducted in 1993 on a purposive sample of family physicians in 39 of 67 rural-designated or urban Pennsylvania counties with low population densities. The physicians identified needs that included patient education materials and programs, community health promotion, federal regulation updates, technical assistance with computers and business management, database software and a videotape lending library, a drug hotline, and mini-fellowships on clinical skill development. A majority of respondents were willing to participate in clinical educational experiences for students and residents. Some physicians indicated a lack of interest in access to information through telecommunications, e.g., video conference referrals and consultations. Overall, findings revealed that family physicians need and are receptive to a variety of practice support and continuing education programs. A practice support program coupled with policy coordination among public and private organizations is likely to lessen complaints by rural primary care physicians.

Clinical Competence↗
PubMed1996

Occlusion edge blur: a cue to relative visual depth.

We studied whether the blur/sharpness of an occlusion boundary between a sharply focused surface and a blurred surface is used as a relative depth cue. Observers judged relative depth in pairs of images that differed only in the blurriness of the common boundary between two adjoining texture regions, one blurred and one sharply focused. Two experiments were conducted; in both, observers consistently used the blur of the boundary as a cue to relative depth. However, the strength of the cue, relative to other cues, varied across observers. The occlusion edge blur cue can resolve the near/far ambiguity inherent in depth-from-focus computations.

Depth Perception↗
PubMed1994

Inaccuracy and instability of sequential movements in Parkinson's disease.

Animal studies suggest that the basal ganglia (BG) provide internal cues to trigger submovements in a movement sequence, with Parkinson's disease (PD) involving a deficiency in this cueing mechanism. However, it is not clear why defective internal cues can produce slow movements, or the extent to which slow movements are indeed the basic movement abnormality or are perhaps a compensatory mechanism for some other primary deficit. In this study we examined a number of the kinematic indices of matched fast movements between PD patients and age-matched controls, performed with and without reductions in visual cues for guidance, in order to delineate the relationship between the internal cue and the kinematic characteristics of these movements. Fourteen patients with PD, and their matched controls, used an electronic pen, which sampled pen-tip position at 200 Hz, and performed a sequence of drawing movements to nine targets upon a WACOM SD 420 graphics tablet. Subjects were trained to perform the movement sequence at a fast speed and were then required to perform the same movement at the same speed with reduced visual cues. Kinematic analysis indicated that, when visual cues were reduced, movements of PD patients became spatially and temporally unstable as they were progressively performed down the sequence. The instability was associated with an abnormal force profile increase in peak movement velocity and target overshoot, which became additive as the submovements progressed. We suggest that defective cue production is the basic deficit in parkinsonian hypokinesia. The defective cue leads to problems synchronising preparatory activity, which then results in abnormalities in movement forces which are characterised by unpredictable and inaccurate movement endpoints. When movements are strung together in a sequence the inaccuracy is additive leading to motor instability.

Aged↗
PubMed1994

Could bradykinesia in Parkinson's disease simply be compensation?

Even normal movements can be slow and hesitant. To distinguish between bradykinesia and the simple slow inefficiency sometimes seen in normal movement, we matched the movement durations of 12 patients with Parkinson's disease (PD) and 12 age-matched controls and examined end-point accuracy, number of submovements, force inefficiency, and relative duration of acceleration and deceleration phases of movement. Subjects used an electronic pen which sampled pen-tip position at 200 Hz, and performed a sequence of drawing movements to nine targets (0.5, 1, or 2 cm diameter) upon a WACOM SD420 graphics tablet. Patients could be trained to move at the preferred speed of controls (and vice versa). When moving at the same fast speed as controls, patient's movements were less accurate (increased end-point spread). Even when moving at their own preferred speed, patients' movements were less efficient (more submovements, more zero crossings in acceleration function) than controls moving at the same speed. If bradykinesia simply reflected increased caution and visual guidance, we would expect patients to exhibit prolonged decelerative phases of movement associated with terminal guidance. However, patients consistently required prolonged accelerative phases of movement, suggesting that there was a problem in generating appropriate movement forces to produce the required end-point accuracy. It is hypothesised that bradykinesia is not simply a compensation for defective preparatory processes, but may reflect a defective internal cue in PD which disrupts and impairs the outflow of motor responses.

Adaptation, Physiological↗
PubMed1994

Severe microphthalmia, diaphragmatic hernia and Fallot's tetralogy associated with a chromosome 1;15 translocation.

A 9-year-old boy with multiple abnormalities including severe bilateral microphthalmia, diaphragmatic hernia and Fallot's tetralogy is presented. He has also been shown to have an apparently balanced de novo reciprocal translocation, 46,XY,t(1;15)(q41;q21.2), which suggests that one of those breakpoints may be the locus for a gene which is important in morphogenesis.

Abnormalities, Multiple↗
PubMed1988

Are double translocations double trouble?

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child. This is not based on theoretical considerations of segregation patterns, but extrapolated from what is known empirically about the viable segregation patterns in carriers of single reciprocal translocations. It assumes that there is no interference with the independent assortment of the two separate exchanges, unless a common participating chromosome is involved. The possibility of an interchromosomal effect has not been taken into consideration.

Congenital Abnormalities↗
PubMed1981

Protection against experimental Pseudomonas aeruginosa infection in mice by active immunization with exotoxin A toxoids.

The immunoprophylactic effect of chemically inactivated Pseudomonas aeruginosa exotoxin A in experimental pseudomonas infections was studied. Exotoxin A toxoids were prepared by Formalin (f-TXD) or glutaraldehyde (g-TXD) treatment. Immunization of mice with three or four doses (10 micrograms each) of f-TXD and the synthetic adjuvant N-acetylmuramyl-L-alanyl-D-isoglutamine (50 micrograms) induced high levels of antiexotoxin A antibodies as measured by passive hemagglutination assay and enzyme-linked immunosorbent assay. Immunization with toxoid alone did not elicit antitoxin. A significant increase in survival time and survival rate (P less than 0.01) was seen in immunized (f-TXD) and in burned and infected mice (50 to 85%) as compared with control mice immunized with formalinized bovine serum albumin (6 to 20%). Virtually 100% survival was obtained when preinfection immunization weas combined with single-dose gentamicin treatment within 24 h of infection. Immunization with g-TXD increased survival time (P less than 0.01) but did not consistently increase survival rate, and the results were not as satisfactory as those with formalinized exotoxin. The data presented indicate that active immunization with formalinized exotoxin A toxoid and adjuvant induced protective immunity to various degrees against infections in mice and could be potentially useful in prophylaxis of P. aeruginosa infections.

ADP Ribose Transferases↗
PubMedDate not supplied

The use of early enteral nutrition in abdominal trauma.

Patients who sustain abdominal trauma become hypermetabolic and require aggressive utilization of early enteral nutrition. The purpose of this article is to discuss the physiology of the gut as it relates to the development of septic sequelae and the role of early enteral nutrition in decreasing septic complications based upon the findings of previously published research. The research clearly supports that there are many benefits associated with the initiation of early enteral nutrition in this patient population.

Abdominal Injuries↗