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D G Young

Publications and source records attributed to D G Young.

At least 19 recordsLinked to original sources
PubMed1992

Possible determination of the vector and reservoir of leishmaniasis in the Dominican Republic.

Two species of sand flies were collected by various methods from sites in the Dominican Republic. Lutzomyia cayennensis hispaniolae was the more common of the two. It was found in wooded habitats from sea level to an elevation of 442 m. This species was observed feeding on lizards (Anolis sp.) in the wild. In the laboratory, it fed only on lizards and only under lighted conditions. The other species, Lu. christophei was only found in the vicinity of seven leishmaniasis case sites. It readily fed on or probed rodents and humans. Although no naturally infected sand flies were collected, in the laboratory Lu. christophei was readily capable of transmitting the Dominican Leishmania parasite to uninfected BALB/c mice. We collected 167 specimens of three species of rodents and three Herpestes auropunctatus (mongoose) from the vicinity of two case sites. All four species are non-endemics introduced in post-Columbian times. Although we were unable to isolate parasites from any of these specimens, four of 44 Rattus rattus from one case site were seropositive for antibodies against Leishmania by indirect fluorescent antibody testing. This represents the first report of transmission of the Dominican Leishmania parasite by a sympatric species of sand fly and suggests that commensal rodents may play a role in the epidemiologic cycle.

Animals↗
PubMed1991

The changing incidence of neural tube defects in Scotland.

The impact of neural tube defects on neonatal surgery has been declining in Scotland over the past two decades. The Scottish statistics for neural tube defects were studied from 1971 to 1988. The incidence of neural tube defects in Scotland has declined from 5.50 to 1.10 per 1,000 births over this period (3.00 to 0.58 per 1,000 births for spina bifida and 2.50 to 0.52 per 1,000 births for anencephaly). Antenatal maternal alpha-fetoprotein (AFP) screening was introduced to Scotland on a wide scale in 1976. The number of terminations for anencephaly peaked in 1980 (85), and for spina bifida in 1981 (70), and both have since declined. The Scottish birth rate has been about 67,000 per year over this period. The declining incidence of neural tube defects is not explained by the effect of antenatal screening and terminations alone. A downward trend was apparent before 1976, and although antenatal screening has had a considerable impact on anencephaly births (peak terminations 89% in 1983), it has had only a modest impact on spina bifida births (peak terminations 53% in 1984). We conclude that the natural decline in incidence of neural tube defects is the major factor in the observed decline in neonatal surgical admissions for these defects.

Abortion, Eugenic↗
PubMed1991

Follow-up of spina bifida children with and without upper renal tract changes at birth.

The aim of this study was to assess 2 groups of children with spina bifida; one with and the other without upper renal tract (URT) changes at birth and to evaluate the outcome of their management. In Group 1, there were 148 patients who had normal URT at birth. They were studied for a mean follow-up of 131 months. Twenty-eight per cent developed URT changes in later life. The median time interval for URT changes to develop between birth and the first assessment which showed abnormal finding, was 33 months and between the last normal URT assessment and the development of URT changes, was 16 months. Six patients with URT changes were treated conservatively and 36 required intervention. Twenty-eight of 42 patients showed initial improvement of URT changes but 25 subsequently deteriorated. In 3 patients renal function deteriorated with renal failure in one and renal impairment in 2. In Group 2, 24 patients who had URT changes present at birth were also studied for a mean follow-up of 115 months. The URT changes in 8 patients deteriorated after the initial assessment over a median time of 15 months. Twelve patients' URT changes improved spontaneously without active intervention over a median time interval of 16 months but 5 subsequently deteriorated. Overall, the prognosis of children with URT changes at birth did not seem to be any worse than children developing changes later in life. Lesions of sacral and thoraco-lumbar regions of the spine were most commonly associated with URT changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Characterization of Leishmania colombiensis sp. n (Kinetoplastida: Trypanosomatidae), a new parasite infecting humans, animals, and phlebotomine sand flies in Colombia and Panama.

Characterization of Leishmania colombiensis sp.n. is presented, which on the basis of biological and molecular criteria, appears to be a new member of the L. braziliensis complex. A total of nine isolates of the new parasite were made in Colombia and Panama between 1980 and 1986: two from human cases of cutaneous leishmaniasis, six from phlebotomine sand flies, and one from a sloth. Although most closely related to L. lainsoni, L. colombiensis sp.n. is clearly distinguishable from other members of the genus by its reactivity with monoclonal antibodies, isoenzyme electrophoresis, and restriction endonuclease fragment patterns of kinetoplast DNA (k-DNA).

Adult↗
PubMed1991

Recent advances in laboratory mass rearing of phlebotomine sand flies.

Recent technical and procedural advances in mass rearing of sand flies have resulted in larger, healthier, and less labor-intensive colonies. We now maintain closed colonies of Phlebotomus papatasi, P. duboscqi, P. argentipes, and Lutzomyia longipalpis which produce up to 1,000 females per week, in excess of colony-maintenance requirements, for use in research. Advances include larval food preparation in acrylic-plastic incubator cabinets, strict regulation of food quantity and moisture in 500-ml plaster-lined rearing jars, use of large plaster-lined adult holding/mating cages and vacuum-powered aspirators for trauma-free handling of adults.

Animal Feed↗
PubMed1990

Pseudomembranous enterocolitis--a potentially lethal disease.

The cases of nine children with pseudomembranous enterocolitis, five of whom died, are reported here. Six had prior antibiotic therapy, and in eight there were other diseases present that were considered to contribute to the development of this disease. Awareness of this condition, which requires aggressive medical and surgical management, is discussed.

Child↗
PubMed1990

Genetic relationships among phlebotomine sand flies (Diptera: Psychodidae) in the verrucarum species group.

Isozyme data were used to identify populations of certain Lutzomyia taxa in the verrucarum species group, mostly in the series townsendi. Lutzomyia youngi Feliciangelis and Murillo and L. spinicrassa Morales, Osorno, Osorno, and Hoyos each have diagnostic allomorphs for phosphogluconate dehydrogenase (6PGDH) and fumarate hydratase (FUM). The 6PGDH and FUM data and those from 6-phospho-fructokinase and phosphoglucomutase distinguish Lutzomyia sp., a new species from Columbia to be described and named later. Data from these enzymes and glucose phosphate isomerase will separate L. townsendi (Ortiz) from the others and from L. longiflocosa Osorno, Morales, Osorno, and Hoyos, L. quasitownsendi Morales, Osorno, Osorno, and Hoyos, and L. sauroida Osorno, Morales, and Osorno (three species that are inseparable using enzyme data). Three other species, L. serrana (Damasceno and Arouck) (series serrana) and L. columbiana (Ristorcelli and Van Ty) and L. andina Osorno, Osorno, and Morales (both in series verrucarum), are morphologically distinct using conventional characters and have fixed diagnostic differences at several enzyme loci. Statistical analyses of the enzyme data using genetic identities (I), differences (D), and the amount of genetic variation among these taxa indicated that such statistics can be as useful in the study of sand fly phylogeny and population genetics as they have been for other organisms. I and D values indicated that L. longiflocosa, L. quasitownsendi, and L. sauroida are very similar (I = 0.991 and D = 0.010) and possibly are populations of the same conspecific species. The levels of divergence, based on combined enzyme data for up to 21 gene loci among the taxa, are discussed, and a dendrogram based on genetic distance is presented. The genetic data confirmed established phylogenetic relationships among the sand fly taxa based on structural similarities.

Animals↗
PubMed1989

Value of antenatal diagnosis of abnormalities of the urinary tract.

OBJECTIVE: To assess the value of antenatal diagnosis of abnormalities of the urinary tract on ultrasonography. DESIGN: Retrospective study. SETTING: Two obstetric units in Glasgow. SUBJECTS: 62 Fetuses in which renal abnormalities were diagnosed on antenatal ultrasonography. INTERVENTIONS: Six fetuses had their bladders aspirated to determine renal function. Fifteen pregnancies were terminated on the basis of the findings on antenatal ultrasonography, and if possible necropsy was performed on the fetuses. In babies who were born alive the final diagnosis was made by postnatal ultrasonography, intravenous urography, radionuclide scanning, cystography, and, in those who died in the early neonatal period, necropsy. Neonates who were referred with a known obstructed kidney had nephrostomy or pyeloplasty. END POINT: Assessment of the value of antenatal diagnosis of renal abnormalities on ultrasonography for babies who had no clinical evidence of disease postnatally. MAIN RESULTS: Eighteen fetuses did not survive birth; the antenatal diagnosis was accurate in all 18. Of the 44 babies born alive, five had normal urinary tracts, in two of whom antenatal ultrasonography had probably indicated a false positive diagnosis. Fourteen babies died during the early neonatal period. Twenty five babies with renal abnormalities were followed up; the antenatal diagnosis was inaccurate for 10 of them, the commonest misdiagnosis being hydronephrosis for multicystic kidney and vice versa, and there was one false positive diagnosis. The initial clinical findings in 14 babies would have led to the early detection of a urological abnormality. In the 30 babies with no clinical evidence of disease the antenatal diagnosis was of definite value in eight, probable value in 15, and marginal value in seven. Overall, an accurate antenatal diagnosis was made in 46 of the 62 cases (74%); in 12 cases renal disease was detected but its specific nature was not determined; and in four cases the diagnosis was misleading. CONCLUSIONS: The overall value of antenatal diagnosis is that it indicates early termination of fetuses with fatal renal disease, prepares parents and medical staff for the likelihood of serious neonatal problems, and shows abnormalities of the urinary tract that may not be detected postnatally.

Abortion, Induced↗
PubMed1989

Adjuvant chemoimmuno- and immunotherapy in Dukes' stage B2 and C colorectal carcinoma: a 7-year follow-up analysis.

A prospectively randomised controlled clinical trial of adjuvant therapy was undertaken, at a single-centre, population-based cancer institute, in patients with Dukes' stages B2 and C colorectal carcinoma after curative surgery. Between 1976 and 1983, 253 patients were randomised to either control (no further therapy after surgery), immunotherapy (oral bacille Calmette-Guérin [BCG] 120 mg once a month) for 5 years or chemoimmunotherapy (oral BCG as above with methyl-cyclohexyl-chloroethyl nitrosourea [meCCNU] 130 mg/m2 on day 1 and 5-fluorouracil [5-FU] 325 mg/m2/day on days 1-5 and 375 mg/m2/day on days 36-40) repeated every 10 weeks for 8 cycles. The median follow-up of patients is now 6.95 years. Of the control, immunotherapy, and chemoimmunotherapy groups 22.35%, 39.28%, and 28.57%, respectively, have relapsed. The log-rank analysis of results shows no disease-free or overall survival advantage for patients receiving adjuvant therapy compared with the control group. Patients receiving adjuvant immunotherapy for stage B2 appear to have a significantly inferior disease-free survival compared with other groups, but their overall survival is similar. There are no significant differences in disease-free or overall survival in the three groups of patients with stage C tumour. Of 82 patients dying, 78.05% died of progressive colorectal carcinoma, 13 patients developed a second malignancy; the remainder died of seemingly unrelated causes.

Adenocarcinoma↗
PubMed1989

Additional Plasmodium species from Anolis lizards of Hispaniola and Panama.

Saurian malaria parasites in the Caribbean were previously represented by only two species, Plasmodium azurophilum and P. floridense. An additional three species of Plasmodium occur on Hispaniola which appear, because of morphometric and qualitative similarities, to be related to South and Middle American species: a subspecies of Plasmodium tropiduri in Anolis cybotes; a population of Plasmodium minasense anolisi in A. cybotes and A. distichus; and another parasite in A. distichus which is designated as a subspecies of a previously undescribed Plasmodium species in Anolis limifrons. Taxonomic descriptions based upon morphology of mature schizonts and gametocytes are given, the previously unknown parasites are described as new species/subspecies, and comparison is made with P. floridense which also occurs in their respective host species. A Fallisia species was also present but is not described. The increased diversity of Plasmodium parasites in Hispaniolan anoles is attributed to colonization of the island by four separate evolutionary lines of Anolis lizards, in comparison to fewer invasions of Jamaica and Puerto Rico, where only P. floridense and P. azurophilum are found.

Animals↗
PubMed1989

Epidemiology of visceral leishmaniasis in Colombia.

Epidemiologic studies were conducted during the period 1986-1988 in a small rural community in Colombia (El Callejon) where visceral leishmaniasis is highly endemic. In this community of 185 people, 14 cases of infantile visceral leishmaniasis were diagnosed in the 9 years 1981-1988. Leishmanin skin testing of a sample of the human residents showed that prevalence of Leishmania chagasi infection increased with age; overall, 51.2% of the subjects had a positive reaction. A canine surveillance program was instituted, using introduced sentinel dogs as well as the indigenous dog population. Eleven of 16 sentinel dogs were infected within 8 months of exposure; mean seroconversion time was 4.4 months. Eleven of 25 seronegative local dogs were also infected during the 26 month period; mean seroconversion time was 8 months. Parasites identified by isozyme electrophoresis as L. chagasi were recovered from 18 of 22 seropositive dogs. Collections of wild animals using baited live traps yielded mainly the neotropical opossum, Didelphis marsupialis. Leishmania chagasi was recovered from 12 of 37 (32.4%) opossums. Six of 681 female Lutzomyia longipalpis collected in the community had flagellates in their guts; cultures from 4 were identified as L. chagasi. These data confirmed that active parasite transmission occurred. The relatively high prevalence of L. chagasi infection found among D. marsupialis captured near human dwellings suggests that these animals may be an important peridomestic reservoir.

Age Factors↗
PubMed1989

Characterization of five new phleboviruses recently isolated from sand flies in tropical America.

Five new phlebotomus fever virus serotypes (Bunyaviridae: Phlebovirus) are described. These viruses, designated Ambe, Ixcanal, Mariquita, Armero, and Durania, were isolated from sand flies (Diptera: Psychodidae) collected in Brazil, Colombia, and Guatemala. Two of the agents were recovered from pools of male sand flies. The new viruses are antigenically related to other members of the phlebotomus fever serogroup by immunofluorescence, but are distinct from the other 39 members of this serogroup by plaque reduction neutralization test.

Animals↗
PubMed1988

Kasabach-Merritt syndrome.

Eight infants with hemangiomata associated with severe consumption coagulopathy are reviewed; three died. The presentations and method of management are discussed. The varied response to different modalities of therapy initiated this report and led to a search of the world literature in an attempt to identify the pattern of response, if any, to particular therapy. From our own experience with two cases and from the review of the literature, it appears that radiotherapy alone or in combination with steroids gives a superior overall treatment in terms of reducing the death rate.

Combined Modality Therapy↗
PubMed1988

Spastic hemiparesis and presumed prenatal embolisation.

An infant with clinical evidence of prenatal right subclavian arterial occlusion subsequently developed left hemiparesis with cystic infarction of the territory of the right middle cerebral artery. Perinatal strokes have not been reported with signs of limb ischaemia at birth; this finding may be a warning of possible simultaneous cerebral infarction.

Female↗
PubMed1988

Neonatal tumours: Glasgow 1955-86.

Fifty one neonatal tumours were diagnosed in Glasgow over a 32 year period. The most common tumours were teratomas (n=19), others being renal tumours (n=9), soft tissue sarcomas (n=8), neuroblastomas (n=7), and others (n=8). Of the total, 31% were malignant. Neonatal tumours pose difficult problems of management, and because of their comparative rarity and the great potential for cure we recommend that all centres dealing with such patients should contribute to and benefit from a Neonatal Tumour Registry.

Eye Neoplasms↗
PubMed1988

Cefotaxime lavage in children undergoing appendicectomy.

In an attempt to reduce postoperative sepsis, a series of randomised, double-blind studies was begun in 1982, using cefotaxime as backbone therapy. Up to 1985 (stages I and II), the best results were obtained using a combination of cefotaxime (75 mg/kg intravenously in 3 doses at 12-hourly intervals) plus metronidazole (10 mg/kg intravenously in 3 doses), both drugs administered 1 hour before surgery (preoperatively) or at anaesthetic induction (peroperatively). In 300 consecutive cases, the wound infection rates were 1% in uncomplicated acute appendicitis and 5% in perforated/gangrenous appendices. The present study (stage III) reports the findings in 401 consecutive patients: 215 treated with the above regimen, either pre- or perioperatively (group 1) and 186 who additionally had peritoneal lavage with cefotaxime 2 g/L during surgery (group 2). There were 16 wound infections overall, 2 among patients administered prophylaxis preoperatively and 14 in those administered prophylaxis perioperatively. All produced mixed cultures, with Escherichia coli, Streptococcus milleri and Bacteroides fragilis predominating. The overall figures for postoperative sepsis are 12/215 (5.6%) in the non-lavage group and 8/186 (4.3%) in the lavage group. Among patients with a perforated and/or gangrenous appendix, the wound infection rate was 8/72 (11.1%) in the non-lavage group (group 1) and 4/66 (6.1%) in the lavage group (group 2). Each group had 2 cases of pelvic abscess.

Appendectomy↗