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Biomedical subjects

R L Bailey

Publications and source records attributed to R L Bailey.

50 records · Page 3Linked to original sources
PubMed1992

A longitudinal study of trachoma in a Gambian village: implications concerning the pathogenesis of chlamydial infection.

In order to investigate risk factors for the acquisition of trachoma, and to study the effect of continued exposure to ocular chlamydial infection on the severity of inflammatory trachoma and its cicatricial sequelae, a longitudinal study was conducted in a Gambian village. Over a 20-month period, the incidence of active (inflammatory) trachoma was significantly higher among those sharing a bedroom with an active case (64/561, 11.4%) than among those who were not exposed in this way (37/658, 5.6%) (relative risk 1.97, 95% confidence interval 1.33-2.90). There was a positive trend in the odds ratio for severe to moderate inflammatory disease versus mild disease as the number of active cases in the bedroom increased, but this failed to achieve statistical significance (P = 0.0506). Individuals with inflammatory trachoma of moderate or severe intensity at one survey were significantly more likely than others to have moderate or severe inflammatory changes at a previous or subsequent survey (odds ratio 14.9, 95% confidence interval 3.9-68.0), implying that host factors may be more important determinants of severity than the frequency of exposure to reinfection.

Adolescent↗
PubMed1992

Genotyping of Chlamydia trachomatis from a trachoma-endemic village in the Gambia by a nested polymerase chain reaction: identification of strain variants.

Direct amplification of the major outer membrane protein (MOMP) gene by polymerase chain reaction (PCR) was used to identify Chlamydia trachomatis in eye swabs from clinically active cases of endemic trachoma in a Gambian village. Chlamydial DNA was detected in 51% of 96 subjects with clinically active disease and in 5% of 37 clinically negative individuals. The PCR detection was combined with typing, using nested primers to variable sequences (VS) 1, 2, and 4 of the MOMP genes to distinguish between trachoma genotypes A, B, and C, respectively. Genotypes A and B were detected in the village, with some individuals harboring both genotypes within the same eye. DNA sequencing revealed strain variants of both genotypes. Typing of genotype and strain variants is now in progress to study trachoma transmission within the village.

Bacterial Outer Membrane Proteins↗
PubMed1991

The impact of medical services on trachoma in a Gambian village: antibiotics alone are not the answer.

We have measured the prevalence of active trachoma in children aged less than 15 years in the Gambian village of Keneba, which has had excellent free medical care and a continuous supply of antibiotics since 1974. The prevalence was 13%, with the peak prevalence (20%) occurring in the 2 to 3-year age group. Of 71 cases diagnosed, only 23 (33%) had complained of ocular symptoms in the previous 3 months, in spite of the fact that 66 (94%) had attended the clinic. Only five had been diagnosed as having trachoma by the duty paediatrician (7%). Compliance with treatment was poor, with only 29 subjects returning for continued treatment (41%), and at follow-up 16 months later 22 of 64 subjects still had active disease (34%). We conclude that the widespread use of antimicrobial agents does not preclude the persistence of endemic disease. Socio-economic improvement or behavioural changes appear necessary for the control of trachoma in endemic areas. In the meantime there is a need for greater awareness of the disease both among clinicians in endemic areas and among the communities afflicted.

Adolescent↗
PubMed1991

Rapid method for processing soil samples for polymerase chain reaction amplification of specific gene sequences.

Bacterial cells can be differentially separated from soil colloids on the basis of their buoyant densities. By using this principle, a modified sucrose gradient centrifugation protocol has been developed for separating bacterial cells from most of the soil colloids. Since the bacterial cell suspension still contained some colloidal soil particles, which inhibited polymerase chain reaction amplification, a new "double" polymerase chain reaction method of analysis was adopted for amplification of Tn5-specific gene sequences. This new protocol allowed rapid detection of small numbers (1 to 10 CFU/g) of bacterial cells present in soil samples.

Base Sequence↗
PubMed1991

Expression of MHC class II antigens by conjunctival epithelial cells in trachoma: implications concerning the pathogenesis of blinding disease.

In an attempt to understand the pathogenesis of corneal changes and conjunctival scarring in trachoma, which are responsible for blindness in some 7 million people worldwide, the surface expression of major histocompatibility complex class II antigens on conjunctival epithelial cells was sought in patients with different clinical features of the disease. Class II expression was significantly associated with active (inflammatory) trachoma, but an independent association with corneal pannus or conjunctival scarring could not be shown. Longitudinal data suggest that class II expression may antedate clinically active disease and persist after it has resolved.

Adolescent↗
PubMed1990

Quantitative cytochemistry of lysosomal structures in rat incisor maturation enamel organ.

Trimetaphosphatase was used as a lysosomal marker in the ruffle-ended maturation ameloblasts and associated papillary cells. Morphometric analysis was carried out of the percentage area of these cells (density) occupied by the various enzyme-reactive lysosomal structures. The density of total TMPase-positive lysosomal structures, tubular lysosomes and multivesicular bodies in ruffle-ended ameloblasts were all significantly greater (p less than or equal to 0.05) in early than in late maturation enamel formation. In papillary cells the same was true of tubular lysosomes, whereas the greater density of enzyme-positive total structures in early maturation was not statistically significant when compared to late maturation. These findings demonstrate a corresponding pattern between enamel-organ lysosomal activity and the period of early enamel maturation when most enamel protein is lost. They support the likely involvement by ruffle-ended ameloblasts and papillary cells in absorption and degradation of exogenous enamel proteins.

Acid Anhydride Hydrolases↗
PubMed1990

Diagnostic peritoneal lavage in evaluation of acute abdominal disease.

Diagnostic peritoneal lavage (DPL) is an established procedure in evaluation of trauma victims but is less well established for use in patients suspected of having acute intra-abdominal disease. Twenty-six seriously ill patients at our institution who had DPL for acute intra-abdominal disease form the basis of this report. Use of DPL indicated sepsis in ten patients; in seven of the ten, findings were confirmed at celiotomy or autopsy. Only one of the ten survived without laparotomy or confirmatory necropsy indicating the result of DPL had been false-positive. Sepsis was not indicated by DPL in 16 patients. Fourteen patients appeared to have true-negative results confirmed by operation (three patients), autopsy (four patients), or survival longer than two weeks (seven patients). Complications occurred in one patient whose DPL showed sepsis. Two patients with negative results of DPL died within two weeks of examination without confirmatory operation or autopsy and could not be evaluated. We therefore, consider the overall diagnostic accuracy in our patient group to be 95%. We recommend the use of DPL in patients suspected of an acute intra-abdominal disease process who are unable to undergo other evaluation for reasons such as critical illness.

Abdomen, Acute↗
PubMed1990

Is diagnostic peritoneal lavage for blunt trauma obsolete?

Diagnostic peritoneal lavage was 97 percent accurate, with a 2 percent false positive rate and a 1 percent false negative rate in this series of 414 patients. The ease, safety, and accuracy of diagnostic peritoneal lavage justify its continued use in evaluating these patients. Recent studies show computerized tomography (CT) can be highly accurate in detecting intra-abdominal injuries after blunt trauma. We reviewed our experience with diagnostic peritoneal lavage (DPL) to evaluate whether the accuracy, safety, speed, and cost justified its continued use. Four hundred fifteen DPLs were performed on 414 patients from February 1, 1983, through December 31, 1987. All DPLs were done by the open technique. The lavage was considered grossly positive if 10 cc gross blood were aspirated. If there were greater than 100,000 red blood cells (RBC)/mm3, greater than 500 white blood cells (WBC)/mm3, elevated amylase or bilirubin, or bacteria or vegetable fibers the lavage was microscopically positive. There were no cases with elevated bilirubin, amylase, or presence of bacteria. All four cases with "rare vegetable fibers" were false positive. Six DPLs were for penetrating trauma to the lower chest or back. There were 291 negative lavages, including five false negatives (1%), and 124 positive DPLs, including seven false positives (2%), resulting in a crude accuracy of 97 percent. Three of the five false negative lavages had a ruptured diaphragm as the only intra-abdominal injury. There was one minor complication. DPL was usually performed in the trauma resuscitation room during the secondary survey. At our institution, the total fees for DPL are +185 less than the fees for CT. DPL is accurate, rapid, safe, and avoids the disruption of patient care that results in the radiology suite. DPL remains our procedure of choice for evaluating blunt abdominal trauma in the adult.

Abdominal Injuries↗
PubMed1989

Lymphoma of the stomach.

A retrospective review revealed 17 lymphomas in a 25-year period (1960-84). Presenting features did not allow differentiation from carcinoma. Preoperative diagnosis was made in 3 patients by endoscopic biopsy. Treatment included apparent complete resection of 12 patients. Incomplete removal following biopsy with or without a drainage procedure was performed on five patients. Radiation therapy was used on ten patients and chemotherapy was used on three patients. There were three 5-year survivors and four others with survival greater than 2 years. All patients surviving more than 2 years had apparent complete resection while five patients also had radiation. One also had chemotherapy. Analysis of our patients with review of other series suggests complete resection with adjacent nodes to be the best approach. Appropriate node sampling, liver biopsy, and removal of the spleen if it appears clinically involved should be done. Postoperative radiation and/or chemotherapy may be indicated only when apparent complete resection is not feasible.

Aged↗
PubMed1985

Adrenalectomy attenuates stimulation-produced analgesia.

Ablation of the adrenal glands potentiates analgesia induced by morphine and attenuates an opioid form of stress-induced analgesia. the adrenal cortex has been implicated in analgesia induced by morphine and enkephalin-like peptides in the adrenal medulla have been suggested to modulate stress-induced analgesia. The effect of adrenalectomy upon analgesia produced by stimulation of the brain has not been investigated. The present investigations demonstrated that antinociception (measured with the tail-flick test) from focal stimulation of the periaqueductal grey was attenuated or abolished after adrenal ablation. These results implicate adrenal hormones in the regulation of the endogenous pain inhibitory system in the brain.

Adrenalectomy↗
PubMedDate not supplied

Transmission ecology of the fly Musca sorbens, a putative vector of trachoma.

Recent evidence suggests that eye-seeking flies are important trachoma vectors. We conducted a series of investigations to identify which species of synanthropic flies are potential vector(s) of this blinding disease in The Gambia. Several species of fly were caught in fish-baited attractant traps placed in villages throughout the year (1997/98) but only 2 species, Musca sorbens and M. domestica, were caught from the eyes of children. M. sorbens comprised < 10% of the total number of flies caught with attractant traps but was responsible for > 90% of fly-eye contacts, the remainder were made by M. domestica. All fly species were more numerous in the wet season than the dry season. Eyes of young children are considered to be the main reservoir of Chlamydia trachomatis, the causative agent of trachoma. Collections of eye-seeking flies from children showed frequent fly-eye contacts (median [interquartile range], 3 [1.5-7] every 15 min). Children with potentially infective ocular or nasal discharge had twice as many fly-eye contacts than children with no discharge (P < 0.001). There was no difference in exposure to fly-eye contacts if a child sat inside or outside a house (P = 0.273). Female flies were more commonly caught from eyes than male (P < 0.001). The presence of Chlamydia DNA was demonstrated by PCR on 2 of 395 flies caught from the eyes of children with a current active trachoma infection. Both positive flies were M. sorbens, one male and the other female. Further elucidation of M. sorbens behavioural ecology and the development of sustainable strategies to control these flies should be a priority. It is likely that M. sorbens is the principal insect vector of trachoma in The Gambia.

Animals↗