Biomedical subjects

M Muldoon

Publications and source records attributed to M Muldoon.

8 recordsLinked to original sources

PubMed2006

Grading infantile cataracts.

PURPOSE: To introduce and describe two methods of grading the severity of infantile cataracts, and thereby propose a useful clinical guide for early surgical intervention. METHODS: Thirty-three subjects, aged 1 week to 8 years, participated in the study. Twenty-two were evaluated soon after birth (1 week), and 11 in childhood (3-8 years). All had isolated infantile cataracts, of which 16 were bilateral and 17 unilateral. Nine cataract types were examined; nuclear (n = 9), lamellar (n = 9), posterior lenticonus (n = 4), persistent hyperplastic primary vitreous (n = 4), posterior polar (n = 3) and single cases of total, cortical, sutural and anterior polar. Grading the infantile cataracts was performed subjectively based on the cataract morphology, density and position using an 11-point (0-10) ordinal scale. Objective measures of the cataracts were performed by scanning and then digitising photo-slit lamp images to provide cataract intensity profiles. Subjects without cataracts acted as controls. RESULTS: Subjective gradings of 0 and 10 were assigned to the clear, cataract-free lens and the total cataract, respectively. Fixed grades of 1 (anterior polar, sutural) and 6 (posterior polar) were assigned to the three remaining cataracts with static morphologies. The five cataracts which were all progressive were given grading ranges, reflecting the initial and likely final morphological states. Objective measures were found to be valuable in indicating the exact position and relative density of the cataract, as well as accurately defining boundaries. CONCLUSIONS: The magnitude and severity of infantile cataracts can be usefully characterised by an 11-point ordinal subjective grading scale. Although subjective grading alone is satisfactory, it can be greatly assisted by objective measures, particularly in the documentation of cataract progression. Cataracts assigned grades 1-4 were considered minor obstructions to vision and therefore not candidates for early surgery. Cataracts graded 5 and above were considered major visual defects, and ideally should be removed early in life.

Cataract↗

PubMed2001

Using human immunodeficiency virus type 1 sequences to infer historical features of the acquired immune deficiency syndrome epidemic and human immunodeficiency virus evolution.

In earlier work, human immunodeficiency virus type 1 (HIV-1) sequences were analysed to estimate the timing of the ancestral sequence of the main group of HIV-1, the virus that is responsible for the acquired immune deficiency syndrome pandemic, yielding a best estimate of 1931 (95% confidence interval of 1915-1941). That work will be briefly reviewed, outlining how phylogenetic tools were extended to incorporate improved evolutionary models, how the molecular clock model was adapted to incorporate variable periods of latency, and how the approach was validated by correctly estimating the timing of two historically documented dates. The advantages, limitations, and assumptions of the approach will be summarized, with particular consideration of the implications of branch length uncertainty and recombination. We have recently undertaken new phylogenetic analysis of an extremely diverse set of human immunodeficiency virus envelope sequences from the Democratic Republic of the Congo (the DRC, formerly Zaire). This analysis both corroborates and extends the conclusions of our original study. Coalescent methods were used to infer the demographic history of the HIV-1 epidemic in the DRC, and the results suggest an increase in the exponential growth rate of the infected population through time.

Acquired Immunodeficiency Syndrome↗

PubMed2001

Pain on injection of prilocaine plain vs. lidocaine with epinephrine. A prospective double-blind study.

BACKGROUND: Prilocaine has been described as causing less pain on injection than lidocaine with epinephrine, possibly because of the higher pH of the prilocaine anesthetic solution. METHODS: Three hundred ten consecutively seen patients in a general practice received a total of 334 maxillary buccal infiltration or inferior alveolar block injections, administered under clinical conditions by one of two dentists. Immediately afterward, patients rated the pain from each injection on a six-point scale. Twenty of these patients (in 21 separate appointments) received, and were asked to rate the pain associated with, a second injection of a contralateral tooth. The authors analyzed the pain response by operator, location of injection, patient's age, patient's sex and anesthetic. RESULTS: The difference in perceived pain between lidocaine and prilocaine was not statistically significant. Regardless of the anesthetic used, the perceived pain was usually no more than mild. Of 334 injections, 292 (87 percent) were rated as causing either no pain or mild pain. CONCLUSIONS: Under clinical conditions, there is no statistically significant difference between injection pain associated with prilocaine plain vs. that associated with lidocaine with 1:100,000 epinephrine. CLINICAL IMPLICATIONS: Since there is no significant difference in associated pain on injection between prilocaine plain and lidocaine with 1:100,000 epinephrine, dentists may prefer lidocaine with epinephrine. Since there is less anesthetic in each cartridge of lidocaine, it may require the use of less anesthetic per patient, and the vasoconstrictor can prolong its duration.

Adolescent↗

PubMed2000

Timing the ancestor of the HIV-1 pandemic strains.

HIV-1 sequences were analyzed to estimate the timing of the ancestral sequence of the main group of HIV-1, the strains responsible for the AIDS pandemic. Using parallel supercomputers and assuming a constant rate of evolution, we applied maximum-likelihood phylogenetic methods to unprecedented amounts of data for this calculation. We validated our approach by correctly estimating the timing of two historically documented points. Using a comprehensive full-length envelope sequence alignment, we estimated the date of the last common ancestor of the main group of HIV-1 to be 1931 (1915-41). Analysis of a gag gene alignment, subregions of envelope including additional sequences, and a method that relaxed the assumption of a strict molecular clock also supported these results.

Acquired Immunodeficiency Syndrome↗

PubMed2000

Iliac crest bone-muscle transfer in periacetabular osteotomy.

Ganz et al reported acetabular osteotomy for extensive acetabular reorientation without changing the acetabular diameter. This article reports our modification of this surgical technique, which preserves the integrity of the tensor fascia latea muscle as well as providing viable bone for bone graft at the anterior iliac osteotomy site. The interval between the sartorius and tensor fascia lata is developed distal to the anterosuperior iliac spine. After iliac osteotomy through the anterosuperior iliac spine, the distal portion of the anterosuperior iliac spine (acetabular segment), along with its slip of tensor fascia lata (1-2 cm), is separated and shaped to fit the anterior bone gap. Two small holes are drilled into that segment and also into the distal cut surface in the anterior portion of the remaining crest so that when the sutures are tightened, the tensor muscle is preserved anatomically and bone grafting is achieved.

Acetabulum↗

PubMed1998

Longitudinal and cross-sectional analysis of cytotoxic T lymphocyte responses and their relationship to vertical human immunodeficiency virus transmission. ARIEL Project Investigators.

The ARIEL Project for the Prevention of HIV Transmission from Mother to Infant was established to evaluate virologic and immunologic parameters during vertical transmission. To determine the strength and breadth of the cytotoxic T lymphocyte (CTL) response and its correlation with human immunodeficiency virus (HIV) transmission, a cross-sectional study was done of 31 HIV-infected pregnant women, of whom 15 transmitted and 16 did not transmit HIV to their infants. The precursor frequencies of CTL specific for HIV-1 gag, pol, nef, and env from 5 different isolates of the clade B of HIV-1 were determined by limiting dilution analysis. Results showed that variable levels of HIV-specific CTL response were present in HIV-infected pregnant women during and after pregnancy. In addition, CTL precursor frequencies specific for pol and nef were higher during pregnancy in nontransmitters than in transmitters. Thus, CTL responding to different HIV antigens may not be contributing equally to the prevention of vertical transmission.

Adult↗

PubMed1997

Maternal HIV-1 viral load and vertical transmission of infection: the Ariel Project for the prevention of HIV transmission from mother to infant.

Most HIV-1 infections of children result from mother-to-infant transmission, which may occur perinatally or postnatally, as a consequence of breast feeding. In this study, the influence of maternal viral load on transmission of infection to infants from non-breast-feeding mothers was examined using samples of plasma and peripheral blood mononuclear cells (PBMCs) collected at several time points during pregnancy and the 6-month period after delivery. These samples were analyzed by several quantitative methods, including virus cultures of PBMCs and polymerase chain reaction (PCR) assays for HIV-1 RNA in plasma and DNA in PBMCs. The risk of transmission increased slightly with a higher viral load, but transmission and nontransmission occurred over the entire range of values for each assay. No threshold value of virus load was identified which discriminated between transmitters and nontransmitters. We also noted a significant rise in viral load and a decline in CD4+ lymphocytes in the six months after delivery. These findings suggest that a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Additional studies are needed to examine the post-partum increase in viremia.

Anti-HIV Agents↗

PubMed1985

Evaluation of reinforcer preferences for profoundly handicapped students.

Five students classified as profoundly/multiply handicapped were trained to use microswitches to indicate reinforcer preferences. The students were trained to emit a designated motoric response (raise arm or raise head) which in turn activated a microswitch. The microswitches were connected to battery-operated toys and devices, and served to provide immediate, contingent consequences to the students for their motoric responding. The results of the investigation were evaluated within a multiple baseline (across students) with alternating treatments (potential reinforcers) design. During baseline, the students were provided with the switches and devices, but the switches were not connected to the devices. During the training conditions, the switches activated the devices. Evaluation of the devices was conducted by recording the cumulative frequency and duration of the students' responses. When the microswitches activated the devices during training, a substantial increase in the duration of motoric responding occurred for all students. In addition, some students performed differentially across devices, suggesting that they had reinforcer preferences.

Adolescent↗