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Biomedical subjects

C Lee

Publications and source records attributed to C Lee.

At least 649 records · Page 36Linked to original sources
PubMed1993

Attitudes, knowledge, and stages of change: a survey of exercise patterns in older Australian women.

This article describes a telephone survey of attitudes and behavior relevant to exercise adoption among 286 Australian women aged 50 to 64. Stages of change identified by the transtheoretical model of behavior change were related to attitudes, knowledge, and demographic variables. In comparison with exercisers, precontemplators were older, had lower exercise knowledge, perceived lower levels of family support for exercise, expected fewer psychological benefits from exercise, and rated exercise as less important than avoiding smoking. The main significant difference between contemplators and those in the action or maintenance stage involved the perception of practical barriers. Despite the limitations of this cross-sectional self-report study, it identifies attitudes and knowledge as potential targets for intervention with middle-aged women.

Aging↗
PubMed1993

Trichinosis with ventilatory failure and persistent myocarditis.

Life-threatening infections with Trichinella spiralis are rare in countries that have adopted laws requiring cooking of raw garbage fed to pigs. Thus such infections may pose a diagnostic dilemma for clinicians unfamiliar with their presentation. We report a case of imported trichinosis in a Mexican national who developed respiratory failure, myocarditis, and sinus arrest. The patient recovered uneventfully after the administration of benzimidazole and corticosteroid drugs, although a pacemaker was required to maintain normal cardiac rhythm. Symptomatic myocarditis is a rare complication of trichinosis that is often associated with increased morbidity and mortality. This report illustrates and reviews important features of the epidemiology, clinical presentation, and management of trichinosis.

Adult↗
PubMed1993

Localization and molecular heterogeneity of sulfated glycoprotein-2 (clusterin) among ventral prostate, seminal vesicle, testis, and epididymis of rats.

In the rat reproductive tract, sulfated glycoprotein 2 (SGP-2) is present in the ventral prostate, seminal vesicle, testis, and epididymis. In the ventral prostate, SGP-2 is associated with the process of programmed cell death, while in the testis and epididymis a role for SGP-2 in sperm maturation has been proposed. Available information suggests that there are both inter- and intra-organ variations in SGP-2 localization, molecular forms, and response to androgen ablation. In the present study, localization of SGP-2 within the ventral prostate, seminal vesicle, and epididymis was compared by immunohistochemistry. In the ventral prostate of intact rats, immunoreactive SGP-2 was confined to a discrete population of epithelial cells lining the proximal ducts. Epithelial cells in other regions of the ventral prostate did not stain for SGP-2. A similar staining pattern was observed for the seminal vesicle; a small population of SGP-2-expressing epithelial cells was found in epithelium that did not stain for SGP-2. The epididymis also demonstrated a non-uniform staining pattern. The caput displayed strong immunoperoxidase reaction over the apical membrane and stereocilia of all principal cells. Principal cells also showed variable degrees of cytoplasmic staining ranging from weak to strongly positive. The corpus and cauda showed a similar staining pattern. After castration, all epithelial cells in the ventral prostate and seminal vesicle became intensely positive for SGP-2 staining. In the caput and cauda epididymis there was an increase in the number of principal cells demonstrating strong intracellular staining for SGP-2. These results suggest that as observed previously in the regressing ventral prostate, increased intracellular SGP-2 staining may also be associated with the regressing epididymis and seminal vesicle. Differences in molecular forms of SGP-2 were investigated by two-dimensional Western and lectin blots. Molecular forms of SGP-2 differed between testis and epididymis but were similar between ventral prostate and seminal vesicle. Prostate and seminal vesicle forms of SGP-2 differed from those of both testis and epididymis. Analysis of terminal carbohydrate present on the various SGP-2 molecular forms also confirmed the existence of heterogeneity. These results demonstrate the presence of multiple molecular forms of SGP-2 in various organs of the male reproductive tract in rats and suggest a possible variation in functional activity and/or half-life of SGP-2 in these organs.

Animals↗
PubMed1993

Lymphocyte activation in HIV-1 infection. I. Predominant proliferative defects among CD45R0+ cells of the CD4 and CD8 lineages.

OBJECTIVES AND DESIGN: The proliferative defects of CD4 and CD8 cells taken from 474 HIV-1-seropositive individuals during various stages of disease were quantitated. Phytohaemagglutinin (PHA) and soluble anti-CD3 were used in optimal mitogenic concentrations in the presence of recombinant interleukin-2 (rIL-2) and conditioned medium, and the proliferation of cells from HIV-1-seropositive donors was assessed in co-culture with HIV-1-seronegative cells in order to exclude effects of cytokine deficiency. Defects within the CD45RA+ ('unprimed') and CD45R0+ ('primed') T-cell populations were also investigated. METHODS: Quantitative immunofluorescence and double and triple labelling in flow cytometry were performed for (1) CD25 (IL-2 receptor alpha chain) expression, (2) lymphocyte and T-cell survival, and (3) blast transformation and proliferation--in relation to the original input of cells for each subpopulation. RESULTS: T cells from normal and HIV-1-seropositive donors were CD25+ at day 1. In HIV-1-seropositive patients a variable number of CD4 and CD8 lymphocytes failed to further increase CD25, and died as a sign of activation-associated lymphocyte death (AALD). Forty-two per cent of asymptomatic subjects, including 32% of those with CD4 cell counts > 400 x 10(6)/l, showed a poor blast transformation (< 30% blasts). Cells from HIV-1-seropositive donors showed poor blast responses when co-cultured with HIV-1-seronegative cells; both CD4 and CD8 cells were handicapped. In asymptomatic HIV-1-seropositive people T cells with the CD45R0+ RA- ('primed') phenotype were three to five times more vulnerable to AALD than the CD45RA+ RO- ('unprimed') cells. In patients in Centers for Disease Control and Prevention (CDC) disease stage IV both CD45R0+ and -RA+ populations were severely affected. CONCLUSIONS: This is the first quantitative analysis to demonstrate that in HIV-1 infection mitogen-stimulated CD45R0+ ('primed') T cells preferentially die upon activation. Both the CD4 and CD8 lineages are affected, as seen in animal models of graft versus host disease. AALD may explain defects of immunological memory. The analysis of AALD may be a suitable assay for studying whether antiviral drugs influence the proliferative responses of lymphocytes.

CD3 Complex↗
PubMed1993

Tc-99m sestamibi uptake by cerebellar metastasis from bronchogenic carcinoma.

Tc-99m sestamibi has been used to detect primary brain and lung tumors. The authors report a patient who underwent brain imaging to differentiate tumor from abscess in the cerebellum because of a ring-like enhancement lesion on a brain CT scan. An abnormal area of increased sestamibi uptake in the right cerebellum was demonstrated planar and on a SPECT imaging. The removed tumor was confirmed to be poorly differentiated metastatic carcinoma.

Aged↗
PubMed1993

Limitations of cervical radiography in the evaluation of acute cervical trauma.

We retrospectively reviewed the medical records and cervical films, computed tomographic (CT) scans, and tomographic studies of 216 consecutive patients with cervical injuries. A trauma series of roentgenograms--a cross-table lateral (CTL), a supine anteroposterior, and an open-mouth odontoid view--was performed in 100%; CT scanning was performed in 100%; and tomography was done in 9% of cases. We determined what percentage of the patients were asymptomatic initially in the emergency department; the total numbers of fractures, subluxations, and dislocations of the cervical spine in these patients; and what percentage of the cervical injuries were not detected with the plain films. Of the 216 patients in the series, 188 (87%) had known signs or symptoms of cervical injury; however, 28 (13%) of the patients were initially asymptomatic with no neurologic deficit. Of these 28, 17 were intoxicated or had mild closed head injuries; however, in 11 (5%) there was no clinical clue to their cervical injury other than a known injury mechanism. Prospectively, 67% of the fractures and 45% of the subluxations and dislocations were not detected by the CTL films, and 32% of the patients, over half of whom had unstable cervical injuries, were falsely identified as having normal spines. Prospectively, the trauma series improved the sensitivity of plain films for detecting cervical injuries but still did not detect 61% of the fractures and 36% of the subluxations and dislocations, and falsely identified 23% of the patients, half of whom had unstable cervical injuries, as having normal cervical spines.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

Transverse process fractures of the cervical vertebrae: are they insignificant?

Transverse process fractures of the cervical vertebrae have been considered rare and insignificant. In a retrospective study of 216 patients with cervical fractures evaluated by plain films and computed tomography, we found that transverse process fractures were common. Transverse process fractures were present in 24% of patients with cervical fractures and accounted for 13.2% of all cervical fractures. Cervical radiculopathy and brachial plexus palsy were present in 10% of patients with transverse process fractures. In 78% of transverse process fractures, CT scanning showed that the fracture extended into the transverse foramen. Vertebral angiography, performed in eight patients with fractures involving the transverse foramen, showed dissection or occlusion of the vertebral artery in seven (88%) instances. Two of these seven patients had clinical evidence of vertebral-basilar artery stroke. Vertebral angiography should be considered when patients with transverse process fractures extending into the transverse foramen develop signs and symptoms of vertebral-basilar artery insufficiency.

Adolescent↗
PubMed1993

Expression, identification and subcellular localization of the proteins encoded by the hepatitis C viral genome.

We have expressed the full-length coding region and selected domains of the hepatitis C virus (HCV) cDNA in mammalian cells by transfection. Using HCV antibody-positive human sera and monospecific antibodies the proteins encoded by the putative structural and non-structural regions of the open reading frame of HCV were identified as core (p22), E1 (gp32-35), E2 (gp68-72), NS2 (p23), NS3 (p72), NS4a and b (p10 and p27) and NS5a and b (p56 and p70). We have also defined the subcellular localizations of the HCV proteins using indirect immunofluorescence assays.

Animals↗
PubMed1993

Rapid and specific detection of the thermostable direct haemolysin gene in Vibrio parahaemolyticus by the polymerase chain reaction.

Synthetic oligonucleotide primers derived from a sequence of the thermostable direct haemolysin (tdh) gene were used in a polymerase chain reaction (PCR) amplification technique to detect this gene in strains of Vibrio parahaemolyticus. A total of 36 TDH-producing, and 89 TDH-negative Vibrio parahaemolyticus strains and 46 other vibrios and enteric pathogens were studied. In all, 36 strains of Vibrio parahaemolyticus from which the tdh gene could be successfully amplified by PCR were found to be TDH-positive in TDH haemolysin assay. No amplification products were obtained from Vibrio parahaemolyticus strains that were TDH-negative in the haemolysin assay or from other vibrios and enteric pathogens, with the exception of two strains. The PCR results were consistent with DNA hybridization tests. The detection limit for the tdh gene by PCR amplification was 40 pg of total DNA, or broth culture containing 1000 viable cells. Amplification products were confirmed by restriction enzyme digestion and Southern blot hybridization. The PCR method could detect the tdh sequences in stool samples from patients with gastroenteritis caused by V. parahaemolyticus. This PCR protocol clearly identified TDH-producing strains of V. parahaemolyticus and provides an alternative to conventional methods for TDH detection by research laboratories, clinical laboratories, regulatory agencies, and the seafood industry.

Base Sequence↗
PubMed1993

The progression of HIV disease in a haemophilic cohort followed for 12 years.

A cohort of haemophilic patients who seroconverted to HIV-1 between October 1979 and July 1985 has been followed to 1 January 1992. The median age at initial seropositivity was 24 years with a range of 2-77 years. By January 1992, 38/111 (34%) had developed AIDS and 39/111 (35%) had died (four of liver failure including one hepatoma). Using Kaplan-Meier plots, the calculated progression to AIDS at 12 years is 45% (95% CI 31, 58): for age > 25 years 63% (95% CI 45, 82), age < 25 years 32% (95% CI 15, 48) P = 0.0001; CMV positive 68% (95% CI 48, 87) CMV -ve 20% (95% CI 8, 32) P = 0.0009. The 12-year progression rate to CD4 + 0.2 or AIDS is 66% (95% CI 55, 76). 21/34 (63%) of patients who are p24 antigen positive have developed AIDS compared to 17/77 (22%) who are p24 antigen negative (= 0.0001). 19/34 (56%) and 20/77 (23%) of those p24 positive and negative respectively have died (P = 0.007). Before antiviral and prophylactic treatment for asymptomatic patients there were nine AIDS cases in 3.84 years experience with CD4+ < 0.05 (1/0.43 years) and since treatment, 10 AIDS cases in 18.22 years (1/1.8 years). Age, CMV status and p24 remain strongly predictive of disease progression. Treatment appears to reduce the incidence of AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1993

The definition and assessment of physical activity in cardiovascular risk reduction research.

Community-wide promotion of physical activity is becoming increasingly relevant in the development of social, economic, and health-related policy. Such research raises issues in the assessment of physical activity on a population basis. This paper reviews definitions of physical activity for cardiovascular risk reduction and the assessment techniques which arise from them, and makes some recommendations, firstly for the identification of appropriate levels of physical activity, and secondly for the development and selection of assessment techniques. It seems that a clearer conception of appropriate activity levels for fitness and for health will require further research with a range of population groups and activity types. Greater standardisation of questionnaires, improved validity of measures, and a greater understanding of possible response biases will also improve the quality of the basic information on which interventions and policies are developed.

Cardiovascular Diseases↗
PubMed1993

Detection of tetracycline resistance determinants in pig isolates from three herds with different histories of antimicrobial agent exposure.

A total of 114 gram-negative fecal isolates from domestic pigs in herds with different histories of antimicrobial agent exposure were screened for the presence of plasmid DNA and specific tetracycline resistance determinants. More than 84% of the isolates harbored plasmid DNA, which ranged in size from 2.1 to 186 kb. A total of 78 isolates (68.4%) were resistant to tetracycline at concentrations greater than 4 micrograms/ml. Plasmid DNAs from about 56% of the tetracycline-resistant isolates hybridized with DNA probes for class A, B, C, and D tetracycline resistance determinants. The class B determinant was the most common determinant (35% of the isolates), followed by the class C determinant (12%) and the class A determinant (1%). About 9% of the isolates contained two determinants on plasmids. None of the plasmids from isolates hybridized with the class D determinant probe. The class C determinant was the most prevalent determinant on plasmids in isolates from pigs not exposed to antimicrobial agents for more than 146 months, while the class B determinant was more prevalent on plasmids in isolates from pigs exposed to either subtherapeutic or therapeutic levels of antimicrobial agents. Most tetracycline resistance determinants were localized on plasmids which were more than 30 kb long. A great number of wild-type tetracycline-resistant Escherichia coli strains were found with the class E determinant on their chromosomes. This study revealed a high prevalence of tetracycline resistance determinants in the fecal flora of pig herds whether or not they were fed with antibiotics.

Animals↗
PubMed1993

Effect of linker insertion mutations in the human immunodeficiency virus type 1 gag gene on activation of viral protease expressed in bacteria.

We have expressed the human immunodeficiency virus type 1 (HIV-1) protease (PR) in bacteria as a Gag-PR polyprotein (J. Luban and S.P. Goff, J. Virol. 65:3203-3212, 1991). The protein displays enzymatic activity, cleaving the Gag polyprotein precursor Pr55gag to the expected products. The PR enzyme is only active as a dimer, and we hypothesized that PR activation might be used as an indicator of polyprotein multimerization. We constructed 25 linker insertion mutations throughout gag and assessed the PR activity of mutant Gag-PR polyproteins by the appearance of Gag cleavage products in bacterial lysates. All mutant constructs produced stable protein in bacteria. PR activity of the majority of the Gag-PR mutants was indistinguishable from that of the wild type. Six mutants, one with an insertion in the matrix (MA), four with insertions in the capsid (CA), and one with insertions in the nucleocapsid (NC), globally disrupted polyprotein processing. When PR was provided in trans on a separate plasmid, the Gag proteins were cleaved with wild-type efficiency. These results suggest that the gag mutations identified as disruptive of polyprotein processing did not conceal the scissile bonds of the polyprotein. Rather, the mutations prevented PR activation in the context of a Gag-PR polyprotein, perhaps by preventing polyprotein dimerization.

Amino Acid Sequence↗
PubMed1993

Children of HIV positive haemophilic men.

All 14 children who were conceived at the time their 12 haemophilic fathers were anti-HIV positive were shown to be HIV negative and to be healthy physically and mentally. Eleven of the 12 female partners have remained anti-HIV negative and one has seroconverted. Despite counselling it is likely that children will continue to be conceived by anti-HIV positive haemophiliacs.

Adult↗
PubMed1993

Interstitial localization of telomeric DNA sequences in the Indian muntjac chromosomes: further evidence for tandem chromosome fusions in the karyotypic evolution of the Asian muntjacs.

The Indian muntjac is believed to have the lowest chromosome number in mammals (2n = 6 in females and 2n = 7 in males). It has been suggested that a series of tandem chromosome fusions from an ancestral Chinese muntjac-like species (2n = 46) may have occurred during the karyotypic evolution of the Indian muntjac. In an earlier study, hybridization signals generated by the Chinese muntjac centromeric heterochromatin DNA probe (C5) were found to be distributed interstitially in the chromosomes of the Indian muntjac, providing supportive evidence for the tandem chromosome fusion theory. In this study, the highly conserved human telomeric DNA sequence (TTAGGG)n was localized by fluorescence in situ hybridization (FISH) on the metaphase chromosomes of three Cervidae species: the Indian muntjac, Chinese muntjac, and woodland caribou. As expected, hybridization signals were observed at the termini of almost every chromosome in all three species. In addition, interstitial hybridization signals were detected in chromosomes 1 and 2 of the Indian muntjac. The observed interstitial telomeric signals appeared to correspond to specific interstitial centromeric heterochromatin sites. These interstitial telomeric signals could represent remnant DNA sequences from the ancestral species telomeres, further supporting the tandem chromosome fusion theory. Furthermore, these observations permit the elucidation of the chromosome sites where breakage and fusion most likely occurred during the restructuring of the ancestral Chinese muntjac-like chromosomes to form the present day Indian muntjac karyotype.

Animals↗
PubMed1993

Population pharmacokinetics of ceftizoxime in premature newborns.

The population pharmacokinetic parameters of ceftizoxime were determined in 50 premature newborns less than 1 week of age (birth weight = 1.8 +/- 0.6 kg) with a clinical diagnosis of suspected sepsis. Each infant received ceftizoxime 25 mg/kg every 12 h intravenously over 30 min for a total of 6 doses. Serum concentrations of ceftizoxime were assayed by HPLC at 0.5, 1, 2.5 and 11.5 h or at 0.5, 1.5, 4.5 and 11.5 h after the first and the sixth dose. A total of 184 serum concentrations following the first dose and 160 following the sixth dose were fit separately and then collectively to a one-compartment model using NONMEM. The separately estimated parameters were not significantly different between the first and the sixth dose. The final parameter estimates were 27.1 ml/h/kg, 333 ml/kg and 8.5 h for clearance, volume of distribution and half-life, respectively. Other factors including gestational and postnatal age were not associated with alterations in ceftizoxime clearance. That the large variability in clearance was decreased from a coefficient of variation of 80 to 50% warrants dosing premature infants on the basis of body weight. The results of this study suggest that 25 mg/kg ceftizoxime every 12 h appears to be an appropriate dosing regimen for premature neonates.

Ceftizoxime↗