Biomedical subjects

C M Long

Publications and source records attributed to C M Long.

At least 19 recordsLinked to original sources

PubMed2001

Parotid mass: Epstein-Barr virus and facial paralysis.

Infectious mononucleosis is a common diagnosis in the pediatric and young adult population. Symptoms include low grade fever, malaise, odynophagia, and cervical lymphadenopathy. Neurological manifestations are uncommon, but include cranial nerve neuropathies. We describe a case of infectious mononucleosis in a pediatric patient who presented with a parotid mass and facial nerve palsy. Diagnosis was confirmed with a monospot test and Epstein-Barr virus antibody panel. The patient was managed conservatively with near total recovery of facial nerve function. This case demonstrates the need to consider infectious etiology prior to surgical intervention of a pediatric patient with facial nerve paresis and a parotid mass.

Child↗

PubMed2001

Fate of linear alkylbenzenes released to the coastal environment near Boston Harbor.

Linear alkylbenzenes (LABs) were used to assess the fates of hydrophobic organic compounds (HOCs) released to a large urban harbor and the adjoining offshore waters. We found that particulate concentrations of the individual C12 LAB isomers in 1996 summertime surface waters decreased from 1 pM in Boston Harbor to 20-200 fM in coastal Massachusetts and Cape Cod Bays. Levels fell to only a few fM in offshore Gulf of Maine locations. These observations were consistent with municipal wastewater in Boston Harbor as the predominant input followed by dispersal via known circulation patterns in this region. Phase-dependent removal rate coefficients for flushing, vertical scavenging, volatilization, photodegradation, and biodegradation of individual LAB isomers were constrained from literature, field observations, and laboratory experiments and combined with estimates of wastewater release rates into a predictive 3-box model. Vertical scavenging, biodegradation, and flushing were predicted to be the most important fate processes for C12 LABs in the Boston Harbor-MA Bay-Cape Cod Bay flow system with about 1% of the harbor releases "surviving" passage. For HOCs such as the relatively bio-recalcitrant LAB, 6-phenyldodecane, it appears that we are at present able to predict the coastal fate of harbor-introduced HOCs in this system within a factor of 2. Contrary to expectations from biodegradation experiments, the ratio of internal-to-external (I/E) LAB isomers decreased offshore in both water and sediment samples, suggesting we are "missing" an important process affecting LAB fates.

Alkylation↗

PubMed2001

Using time- and size-resolved particulate data to quantify indoor penetration and deposition behavior.

Because people spend approximately 85-90% of their time indoors, it is widely recognized that a significant portion of total personal exposures to ambient particles occurs in indoor environments. Although penetration efficiencies and deposition rates regulate indoor exposures to ambient particles, few data exist on the levels or variability of these infiltration parameters, in particular for time- and size-resolved data. To investigate ambient particle infiltration, a comprehensive particle characterization study was conducted in nine nonsmoking homes in the metropolitan Boston area. Continuous indoor and outdoor PM2.5 and size distribution measurements were made in each of the study homes over weeklong periods. Data for nighttime, nonsource periods were used to quantify infiltration factors for PM2.5 as well as for 17 discrete particle size intervals between 0.02 and 10 microns. Infiltration factors for PM2.5 exhibited large intra- and interhome variability, which was attributed to seasonal effects and home dynamics. As expected, minimum infiltration factors were observed for ultrafine and coarse particles. A physical-statistical model was used to estimate size-specific penetration efficiencies and deposition rates for these study homes. Our data show that the penetration efficiency depends on particle size as well as home characteristics. These results provide new insight on the protective role of the building shell in reducing indoor exposures to ambient particles, especially for tighter (e.g., winterized) homes and for particles with diameters greater than 1 micron.

Air Movements↗

PubMed2001

Photo amidoglycosylation of an allal azidoformate. Synthesis of beta-2-amido allopyranosides.

[figure: see text] Photolysis of an allal C-3 azidoformate provoked intramolecular nitrene insertion into the glycal C=C unit and allowed direct incorporation of alcohol nucleophiles as beta-disposed substituents at C-1. The 2-amido allopyranoside products were elaborated via N-acylation and selective oxazolidinone hydrolysis, providing N-Boc-protected 2-amino sugars and simplifying stereochemical assignments. Synthesis of the potentially labile allal azidoformate was achieved via reaction of the corresponding carbonyl imidazolide with trimethylsilyl azide, facilitated by dibutyltin oxide.

Amides↗

PubMed2001

Laryngotracheal reconstruction in canines: fixation of autologous costochondral grafts using polylactic and polyglycolic acid miniplates.

OBJECTIVE: To examine the feasibility of a new method of laryngotracheal reconstruction (LTR) that uses a bioabsorbable plating system consisting of polylactic and polyglycolic acid and provides some advantages over currently used methods. DESIGN AND INTERVENTIONS: Anterior subglottic stenosis was created in 10 beagles that then underwent LTR using an autologous costochondral graft. External laryngotracheal framework and cartilage grafts were secured using a sheet and screws made from a copolymer composed of polylactic and polyglycolic acid. Animals were humanely killed at 40, 60, and 90 days, and specimens were submitted for pathological examination. Histologic analysis included evaluation for inflammatory reaction, polylactic and polyglycolic acid incorporation into cartilage, cartilage necrosis, cartilage remodeling, and graft epithelialization. RESULTS: All animals underwent LTR after creation of a subglottic stenosis without episodes of airway compromise. After LTR, all airways were returned to prestenosis diameter without significant complication, and all animals were immediately extubated after surgery without difficulty. After the animals were killed, distraction of the stenotic cricoid area was demonstrated in 100% of the cases. Significant necrosis was noted in 2 of 10 grafts grossly; however, histologic analysis demonstrated significant areas of viable cartilage, areas of cartilage remodeling, and good epithelialization despite graft necrosis. Complete epithelialization of grafts was noted in the other 8 specimens. CONCLUSIONS: Using a canine model, we demonstrated a bioabsorbable plating system that offers an effective method for LTR. This model has the advantages of providing external support to the operated laryngeal and tracheal framework, elimination of the difficulties of suture placement, and potential future failure while offering rigid external fixation of a cartilage graft.

Absorbable Implants↗

PubMed2001

Factorial invariance for combined Wechsler Adult Intelligence Scale-Revised and Wechsler Memory Scale-Revised scores in a sample of clients with alcohol dependency.

This study examined the joint factor structure of the WAIS-R and WMS-R in a sample of 289 participants (mostly males) with alcohol dependency. In a confirmatory phase we contrasted a range of factor models derived from previous analyses of the Wechsler scales. The best fitting model incorporated five factors representing Verbal Comprehension, Perceptual Organization, Attention-Concentration, Verbal Memory, and Visual Memory, with reassignment of factor loadings for two subtests. The invariance of the measurement model was then examined comparing data from a large sample of healthy participants (J. R. Carstairs & E. A. Shores, 1999). The results indicated that the number of factors was invariant across samples, and four of the factors satisfied the criterion of partial measurement invariance.

Adolescent↗

PubMed2001

A pilot investigation of the relative toxicity of indoor and outdoor fine particles: in vitro effects of endotoxin and other particulate properties.

In this study we assessed the in vitro toxicity of 14 paired indoor and outdoor PM(2.5) samples (particulate matter < or =2.5 microm in aerodynamic diameter) collected in 9 Boston-area homes. Samples were collected as part of a large indoor particle characterization study that included the simultaneous measurement of indoor and outdoor PM(2.5), particle size distributions, and compositional data (e.g., elemental/organic carbon, endotoxin, etc.). Bioassays were conducted using rat alveolar macrophages (AMs), and tumor necrosis factor (TNF) was measured to assess particle-induced proinflammatory responses. Additional experiments were also conducted in which AMs were primed with lipopolysaccharides (LPS) to simulate preexisting pulmonary inflammation such as that which might exist in sick and elderly individuals. Significant TNF production above that of negative controls was observed for AMs exposed to either indoor or outdoor PM(2.5). TNF releases were further amplified for primed AMs, suggesting that preexisting inflammation can potentially exacerbate the toxicity of not only outdoor PM(2.5) (as shown by previous studies) but also indoor PM(2.5). In addition, indoor particle TNF production was found to be significantly higher than outdoor particle TNF production in unprimed AMs, both before and after normalization for endotoxin concentrations. Our results suggest that indoor-generated particles may be more bioactive than ambient particles. Endotoxin was demonstrated to mediate proinflammatory responses for both indoor and outdoor PM(2.5), but study findings suggest the presence of other proinflammatory components of fine particles, particularly for indoor-generated particles. Given these study findings and the fact that people spend 85-90% of their time indoors, future studies are needed to address the toxicity of indoor particles.

Air Pollutants↗

PubMed2000

Characterization of indoor particle sources using continuous mass and size monitors.

A comprehensive indoor particle characterization study was conducted in nine Boston-area homes in 1998 in order to characterize sources of PM in indoor environments. State-of-the-art sampling methodologies were used to obtain continuous PM2.5 concentration and size distribution particulate data for both indoor and outdoor air. Study homes, five of which were sampled during two seasons, were monitored over week-long periods. Among other data collected during the extensive monitoring efforts were 24-hr elemental/organic carbon (EC/OC) particulate data as well as semi-continuous air exchange rates and time-activity information. This rich data set shows that indoor particle events tend to be brief, intermittent, and highly variable, thus requiring the use of continuous instrumentation for their characterization. In addition to dramatically increasing indoor PM2.5 concentrations, these data demonstrate that indoor particle events can significantly alter the size distribution and composition of indoor particles. Source event data demonstrate that the impacts of indoor activities are especially pronounced in the ultrafine (da < or = 0.1 micron) and coarse (2.5 < or = da < or = 10 microns) modes. Among the sources of ultrafine particles characterized in this study are indoor ozone/terpene reactions. Furthermore, EC/OC data suggest that organic carbon is a major constituent of particles emitted during indoor source events. Whether exposures to indoor-generated particles, particularly from large short-term peak events, may be associated with adverse health effects will become clearer when biological mechanisms are better known.

Air Pollution, Indoor↗

PubMed1998

Evaluation of a commercial PCR kit for diagnosis of cytomegalovirus infection of the central nervous system.

We evaluated the AMPLICOR cytomegalovirus (CMV) PCR kit for the diagnosis of neurologic CMV infections on 43 positive and 112 negative archived cerebrospinal fluid specimens originally tested by an in-house PCR method. The AMPLICOR kit showed sensitivity and specificity of 95 and 100%, respectively, versus the home-grown assay, indicating its utility in this clinical setting.

Base Sequence↗

PubMed1998

Detection of cytomegalovirus in plasma and cerebrospinal fluid specimens from human immunodeficiency virus-infected patients by the AMPLICOR CMV test.

We have developed the AMPLICOR CMV Test, which is rapid and sensitive for the detection of cytomegalovirus (CMV) in plasma and cerebrospinal fluid (CSF) specimens. The test incorporated an internal control in the reaction mixture to monitor the amplification efficiency and the presence of inhibitors. The AMPLICOR CMV Test was very specific in detecting 12 clinical CMV isolates and four laboratory CMV strains tested. Cross-reactivity with 26 non-CMV pathogens was not observed. The AMPLICOR CMV Test requires only 50 microl of specimen (plasma or CSF) for processing. The performance of the AMPLICOR CMV Test was compared to those of the CMV antigenemia assay and the conventional tube culture method. Among 112 plasma specimens from 43 human immunodeficiency virus-infected patients, CMV was detected in 20 (18%) of the specimens by the AMPLICOR CMV Test, 21 (19%) of the specimens by the CMV antigenemia assay, and 10 (9%) of the specimens by culture. In CSF specimens from AIDS patients, CMV was detected in 10 of 58 (17%) specimens tested by the AMPLICOR CMV Test, 5 of 28 (18%) specimens tested by the antigen assay, and none of the 25 specimens tested by culture. While the performance of the AMPLICOR CMV Test in this study was comparable to that of the CMV antigen assay, processing of specimens by the AMPLICOR CMV Test was much simpler than that by the antigen assay; in addition, the antigen assay requires greater than 10(5) leukocytes from blood or 1 ml of CSF to perform the assay. Our study suggested that the AMPLICOR CMV Test could provide a rapid and sensitive assay for the detection of CMV in plasma and CSF specimens.

AIDS-Related Opportunistic Infections↗

PubMed1994

Herpes simplex type 2 in a patient with Mollaret's meningitis: demonstration by polymerase chain reaction.

We describe a patient with recurrent self-limited aseptic meningitis meeting the criteria for Mollaret's syndrome, in whom extensive serological investigation and cerebrospinal fluid analysis failed to reveal a specific cause. Using polymerase chain reaction techniques to amplify herpes simplex viral DNA, we were able to identify the presence of herpes simplex virus type 2 in the cerebrospinal fluid. The duration of clinical illness may have been shortened by treatment with intravenous acyclovir. We suggest that herpes simplex virus may be a more common cause of aseptic meningitis than has been demonstrated by current commonly available serological and culture techniques.

Adult↗

PubMed1990

Sequence analysis of arcelin 2, a lectin-like plant protein.

The nucleotide sequence of the cDNA clone encoding arcelin 2 (Arc2), one member of a family of closely related lectin-like plant toxins from wild bean accession, is presented. The sequence contains a 265-amino acid (aa) open reading frame and is 99.3% homologous to Arc1, another of the four electrophoretic variants with proven antibiosis characters. These two proteins differ by four aa residues. Based on cross hybridizations of RNAs, it is assumed that Arc4 is more divergent than Arc1 and Arc2. Furthermore, it is likely that at least three of the variants are polypeptides of similar size and the observed molecular weight differences between them are due to differences in the number of glycosylation sites.

Amino Acid Sequence↗

PubMed1988

Cloning, characterisation and regulation of an alpha-amylase gene from Streptomyces venezuelae.

The alpha-amylase gene (aml) of Streptomyces venezuelae ATCC15068 was cloned in Streptomyces lividans TK24 using the plasmid vector pIJ702. Sub-cloning and exonuclease III deletion experiments localised the sequences required for alpha-amylase production to a segment of 2.05 kb. Low-resolution nuclease S1 mapping revealed a aml transcript of approx. 1.7 kb, and the extracellular form of alpha-amylase was estimated by SDS-polyacrylamide gel electrophoresis to be 59 kDa, suggesting that aml mRNA is monocistronic. The nucleotide sequence of aml was determined and high-resolution nuclease S1 mapping experiments identified transcripts that appeared to initiate at a promoter identical to that of the alpha-amylase gene of Streptomyces limosus [Long et al., J. Bacteriol. 169 (1987) 5745-5754]. Transcription of aml in S. venezuelae, and of the cloned gene in Streptomyces coelicolor A3(2), was induced by maltose and repressed by glucose. Glucose repression in S. coelicolor A3(2) depended on a functional glucose kinase gene. The predicted amino acid sequence of the extracellular enzyme was very similar (75% identity) to the alpha-amylase of S. limosus and shared with this enzyme a strong susceptibility to tendamistat, a potent inhibitor of mammalian alpha-amylases. Sequence inspection revealed a putative signal sequence of 28 amino acids that preceded the probable signal peptidase cleavage site.

Amino Acid Sequence↗

PubMed1988

Molecular cloning of two types of GAP complementary DNA from human placenta.

The ras p21 GTPase-activating protein (GAP) was purified from human placental tissue. Internal amino acid sequence was obtained from this 120,000-dalton protein and, by means of this sequence, two types of complementary DNA clones were isolated and characterized. One type encoded GAP with a predicted molecular mass of 116,000 daltons and 96% identity with bovine GAP. The messenger RNA of this GAP was detected in human lung, brain, liver, leukocytes, and placenta. The second type appeared to be generated by a differential splicing mechanism and encoded a novel form of GAP with a predicted molecular mass of 100,400 daltons. This protein lacks the hydrophobic amino terminus characteristic of the larger species, but retains GAP activity. The messenger RNA of this type was abundantly expressed in placenta and in several human cell lines, but not in adult tissues.

Amino Acid Sequence↗

PubMed1988

Analysis of HLA-DP allelic sequence polymorphism using the in vitro enzymatic DNA amplification of DP-alpha and DP-beta loci.

Allelic sequence variation of the HLA DP-alpha and DP-beta genes has been analyzed in a panel of 34 DP-typed cell lines. The polymorphic second exon of these genes was specifically amplified in vitro by the polymerase chain reaction method, using the thermostable DNA polymerase of Thermus, aquaticus. The analysis of M13 clones containing the amplified DP-beta sequences revealed a total of 14 allelic variants. In general, specific allelic DP-beta sequences were associated with each of the defined DPw1-w6 types, with beta allele subtypes revealed for the DPw2 and DPw4 specificities. An additional six DP-beta alleles which did not correlate with any of the T cell-defined specificities (DP "blanks") were also identified. Only the two previously characterized alleles of DP-alpha were detected. These observations suggest that the T cell-defined DP specificities are determined by polymorphic residues on the beta-chain. The sequence polymorphisms in DP-beta are clustered in a few specific regions, and can be detected using sequence-specific oligonucleotide probes and polymerase chain reaction amplified DNA in a rapid dot-blot format. This approach provides a simple and informative method of DP typing. The DP-beta sequences derived from four DP-typed celiac disease patients were compared with the distribution of DP-beta alleles in control individuals.

Alleles↗

PubMed1988

Sequence analysis of HLA class II genes from insulin-dependent diabetic individuals.

To examine the nature of HLA-linked genetic susceptibility to insulin-dependent diabetes mellitus (IDDM), we compared HLA class II gene sequences from IDDM patients and control individuals. Genomic libraries were constructed from two siblings with IDDM, typed serologically as DR3,w6 and DR3,4. These libraries represent the HLA haplotypes (DR3, DR4) most frequently associated with IDDM, as well as one haplotype found less often. Individual genomic clones were identified and assigned to specific loci and haplotypes. The nucleotide sequence was then determined from the variable second exon from the HLA-DQ alpha, DQ beta, and DR beta genes from all three haplotypes. Sequence variation within the DQ alpha genes could not be correlated with the disease. For all three haplotypes, the DQ alpha sequence from the IDDM patient was identical to the DR-matched control sequence. Similarly, for the DR3 haplotype, the DQ beta sequences matched all control DR3 alleles. The DQ beta sequence from the DR4 haplotype was identical to the predominant DR4 allele (DQ beta 3.2) but differed at four amino acid residues from the other major DR4 DQ beta sequence (DQ beta 3.1) found rarely among IDDM patients. Sequence analysis of the DQ beta gene from the DRw6 haplotype revealed a new allele that differed from the DQ beta allele from a control DR6 allele at two residues. The DR beta genes from these three haplotypes also did not show any sequence features uniquely associated with IDDM, although the frequency of certain allelic variants in all three of these haplotypes may be altered in the IDDM population. A particular group of amino acids was found to be shared between the DR beta-1 alleles from the DR4 and DRw6 haplotypes and may be involved in genetic susceptibility to IDDM.

Amino Acid Sequence↗

PubMed1988

Sequence analysis of the HLA-DR beta and HLA-DQ beta loci from three Pemphigus vulgaris patients.

Pemphigus vulgaris (PV) is an autoimmune dermatologic disease that has been associated with the HLA serotypes DR4 and DRw6. In studying this association at the level of coding sequence polymorphism, we have determined the nucleotide sequences of the second variable exons from the HLA-DR beta and DQ beta loci from three PV patients with the HLA serotypes DR4/4, DR4/5, and DR4/5. These exons were enzymatically amplified by polymerase chain reaction (PCR) and cloned directly into an M13 vector for DNA sequencing. Analyses of amino acid sequences translated from the nucleotide sequence data show that all three patients contained a DR4 DR beta I sequence associated with the Dw10 DR4 subtype specificity, a relatively rare subtype among U.S. Caucasian DR4 haplotypes. The DQ beta sequence from three of the four DR4 haplotypes was identical to the sequence (DQB3.2) found on 60-80% of control DR4 haplotypes. These observations suggest that the amino acid residues at position 68, 69, and 72 of the DR beta I chain that distinguish Dw10 from the other DR4 subtypes may be involved in disease susceptibility.

Amino Acid Sequence↗

PubMed1988

Allelic sequence variation of the HLA-DQ loci: relationship to serology and to insulin-dependent diabetes susceptibility.

Analysis of sequence variation in the polymorphic second exon of the major histocompatibility complex genes HLA-DQ alpha and -DQ beta has revealed 8 allelic variants at the alpha locus and 13 variants at the beta locus. Correlation of sequence variation with serologic typing suggests that the DQw2, DQw3, and DQ(blank) types are determined by the DQ beta subunit, while the DQw1 specificity is determined by DQ alpha. The nature of the amino acid at position 57 in the DQ beta subunit is correlated with susceptibility to insulin-dependent diabetes mellitus. This region of the DQ beta chain contains shared peptides with Epstein-Barr virus and rubella virus.

Alleles↗