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Biomedical subjects

W S James

Publications and source records attributed to W S James.

17 recordsLinked to original sources

Molecular epidemiology of dengue virus type 3 in Venezuela.

During the past 40 years, dengue haemorrhagic fever and dengue shock syndrome (DHF/DSS) have emerged in humans, with approximately 3 million cases reported and over 58 000 deaths. Dengue virus serotypes 1, 2 and 4 (DENV-1, -2 and -4) have been co-circulating in Venezuela for at least the past 10 years, causing minor or major outbreaks of dengue fever (DF) and DHF/DSS. The first recorded outbreak due to DENV-3 in Venezuela dates to 1964 and the virus then seems to have disappeared. However, DENV-3 re-appeared recently (in July, 2000) in Venezuela after 32 years of absence and produced a prolonged major outbreak, which, by the end of 2001, involved 83 180 cases of dengue, mostly DF (92 %). Previous phylogenetic studies revealed that the DENV-3 circulating during the 1960s Latin American outbreak was a genotype V virus. To gain a better understanding of the nature of the current epidemic, the complete sequence was determined of the envelope (E) gene of 15 Venezuelan DENV-3 viruses isolated during 2000 and 2001 from patients presenting with different disease severity. Sequence data were used in phylogenetic comparisons with global samples of DENV-3. Analysis revealed that the strain circulating in Venezuela is closely related to isolates that were previously present in Panama and Nicaragua in 1994 and since then have spread through Central American countries and Mexico. This study also confirms previous reports showing that the DENV-3 strain currently circulating in the Americas is related to the strain that caused DHF epidemics in Sri Lanka and India in 1989-1991 (genotype III). Finally, no evidence of the re-emergence of the strain that circulated in Venezuela in the late 1960s and 1970s (genotype V) was found.

Americas↗

Neurological manifestations of dengue infection.

BACKGROUND: Severe forms of dengue, the most important arboviral infection of man, are associated with haemorrhagic disease and a generalised vascular leak syndrome. The importance of dengue as a cause of neurological disease is uncertain. METHODS: During 1995, all patients with suspected CNS infections admitted to a referral hospital in southern Vietnam were investigated by culture, PCR, and antibody measurement in serum and CSF for dengue and other viruses. FINDINGS: Of 378 patients, 16 (4.2%) were infected with dengue viruses, compared with four (1.4%) of 286 hospital controls (odds ratio [95% CI] 3.1 [1.7-5.8]). Five additional dengue positive patients with CNS abnormalities were studied subsequently. No other cause of CNS infection was identified. Seven infections were primary dengue, 13 secondary, and one was not classified. Ten patients had dengue viruses isolated or detected by PCR, and three had dengue antibody in the CSF. 12 of the 21 had no characteristic features of dengue on admission. The most frequent neurological manifestations were reduced consciousness and convulsions. Nine patients had encephalitis. No patient died, but six had neurological sequelae at discharge. Phylogenetic analysis of the four DEN-2 strains isolated mapped them with a DEN-2 strain isolated from a patient with dengue haemorrhagic fever, and with other strains previously isolated in southern Vietnam. INTERPRETATION: In dengue endemic areas patients with encephalitis and encephalopathy should be investigated for this infection, whether or not they have other features of the disease.

Adolescent↗

Postmortem electrical excitability of skeletal muscle: preliminary investigation of an animal model.

Presented is a preliminary study of the feasibility of using an animal model to investigate the postmortem time-dependent decay in muscular response, when subjected to electrical stimulation and to develop an animal model for the assessment of the use of electrical excitability as a method for determining the postmortem period of a human corpse. Analysis of the results shows a correlation between the rate of decay of muscular response with the postmortem interval.

Animals↗

The recognition of chimeras of rat and human CD4 by HIV-1 gp120 and by monoclonal antibodies.

The use of chimeras of rat and human CD4 to probe the HIV-1 gp120 and antibody binding properties of CD4 is reviewed. Short segments of human CD4 sequence were substituted for the equivalent regions of rat CD4 which does not bind gp120, and analysis of the properties of these chimeras established: (i) that residues 33-58 of the NH2-terminal domain of human CD4 encompass the high-affinity gp120 binding site; and (ii) that chimeras containing residues 33-62 mediate HIV-1 infection. The chimera-binding specificities of gp120 and a large panel of anti-CD4 antibodies were also determined. This allowed a critical test of the popular notion that receptor mimics appear at high frequency among antibodies elicited by immunization with receptor ligands and that anti-idiotypic antibodies can be used to identify novel receptors. The data suggest that such mimics appear infrequently, if at all, a result which is consistent with the failure of the anti-idiotype approach to identify new genes encoding receptors with prescribed functions.

Amino Acid Sequence↗

Introducing quality assurance to a state hospital medical staff.

Establishing a quality assurance program in a developing state hospital requires considering the unique problems of being a physician in such a setting. The hospital and medical staff must be developed to the point where consideration of quality of care is a feasible goal. Managers can take advantage of the interests of individual medical staff as well as serendipitous factors promoting a program.

Hospitals, Psychiatric↗

The cytochrome oxidases of Bacillus subtilis: mapping of a gene affecting cytochrome aa3 and its replacement by cytochrome o in a mutant strain.

A mutant of Bacillus subtilis has been isolated that fails to grow on succinate as the source of carbon, yet grows on glucose. Intact cells of the mutant and cytoplasmic membranes derived therefrom lack cytochromes a and a3 but contain a cytochrome o-like pigment, which forms a photodissociable compound with CO and is reactive with oxygen. The mutation in the genome has been located and lies at about 130 degrees on the chromosomal map between the metC and pyrD loci. The designation cox is suggested for this gene.

Bacillus subtilis↗

The head-tail linker protein of bacteriophage T5: genetic and immunological studies.

We investigated the properties of amber mutants of coliphage T5 defective in a late stage of phage assembly. The non-functional heads synthesized by mutants am25 or am158 were unable to combine with functional tails to produce viable phage particles. These mutants were shown to lack a single protein, designated the head-tail linker protein (HTLp), which was identified by polyacrylamide gel electrophoresis and Western blot analysis and had an Mr of 18,000. An extract containing the HTLp, when added to the HTLp-deficient heads, restored their ability to combine with functional tails.

Electrophoresis, Polyacrylamide Gel↗

Medicine court: Rogers in practice.

The authors conducted a prospective study of the impact of the Rogers decision involving patients' right to refuse treatment during the first year (1983-1984) of its implementation in the Massachusetts facility for the criminally insane. They learned that of the 98 cases submitted to the probate court, only 39 were heard. The court found that 35 (90%) of the 39 patients whose cases were heard lacked competence to make treatment decisions. Hearings occurred 2-7 months after petitions were signed by treating physicians. In arriving at the decisions the court appeared to rely more on reports of violent incidents than on evidence of mental illness or testimony about competence.

Commitment of Persons with Psychiatric Disorders↗

Host-adaptive antigenic variation in Bunyaviruses.

Bunyamwera virus and snowshoe have virus (family Bunyaviridae) were passaged up to six times through mosquito cells in culture and the resultant viruses were compared to the input, mammalian cell-passed virus using monoclonal antibodies raised against the input virus. The mosquito cell-adapted virus population consisted of mutants which were better adapted to replication in the new host than was the input mammalian cell-passed virus and were differentially susceptible to neutralization by antibody.

Aedes↗

Cervical accessory respiratory muscle function in a patient with a high cervical cord lesion.

The function of the accessory respiratory muscles (ARM) of the neck were studied in a quadriplegic patient suffering from a C2-3 lesion of the cervical spinal cord. Subtotal expiratory paralysis resulted in an essentially complete loss of expiratory reserve volume such that residual volume and functiona residual capacity were equal (RV=FRC). Tidal volume and vital capacity were severely reduced. Being extrinsic to the chest, the ARM of the neck functioned independently of changes in thoracic gas volume; however, their performance appeared posture-dependent, and was less efficient in the sitting position. Despite the fact that the ARM preferentially expanded the upper part of the ribcage, significant V/Q mismatch did not seem to occur. Voluntary use of glossopharynegeal breathing (GPB) greatly enhanced the patient's ventilatory capability. Flow volume data during GPB documented the efficiency of the glossopharyngeal muscles, which function as a positive pressure pump to force air into the lungs.

Adult↗

The role of bronchial arteriography and therapeutic embolization in hemoptysis.

A case is presented which demonstrates the value of bronchial arteriographic studies in localizing and treating hemoptysis. The patient was bleeding from an old post-tuberculous bulla and for several reasons was not a candidate for surgery. Bronchial arteriographic studies demonstrated both hypervascularity in the region of the cavity and also a mycotic aneurysm of a bronchial artery. After therapeutic embolization with gelatin (Gelfoam), the hypervascularity and aneurysm were no longer opacified. Active bleeding abruptly ceased and, except for a single mild recurrence, has not recurred during the three months since therapeutic embolization. The major theoretic risk of bronchial arteriographic study and therapeutic embolization is spinal injury. It is believed that permanent injury can almost be avoided, providing proper technique is used.

Bronchial Arteries↗

Ethyl chloride: an ineffective bacteriostatic or cidal agent for arthrocentesis.

The local and general anesthetic properties of ethyl chloride have been well delineated. The purpose of this study was to determine if ethyl chloride, when used as a local anesthetic, had any bacteriostatic or cidal effects on the normal array of skin flora. Fifteen different aerobic bacteria or fungi were collected from pure cultures. A total of 30 specimens were sprayed; 2 specimens of each of the 15 bacteria were sprayed with ethyl chloride for both 5 and 10 seconds. These specimens then were restreaked once the ethyl chloride had evaporated, and were incubated for 24 hours. At 24 hours the cultures were checked and found to have no significant growth inhibitions. It is thus concluded that ethyl chloride alone does not have any bacteriostatic or cidal effects on these commonly found skin flora.

Anesthetics, Local↗