Biomedical subjects
Publications and source records attributed to R C Sanders.
Congenital anomalies of the genitourinary system represent the commonest fetal anomaly. The sonographic findings in hydronephrosis, multicystic kidney (dysplastic kidney), polycystic kidney, and renal agenesis are reviewed.
Eighty-seven cases of subacute sclerosing panencephalitis (SSPE) were diagnosed from September 1988 to April 1991 in Papua New Guinea (PNG), by demonstration of high-titre measles-specific antibodies in cerebrospinal fluid (CSF). For 1990 the annual incidence of SSPE, for the study provinces, was calculated to be 56 cases per million under 20 years of age and it is expected that this figure will be higher in 1991. The mean age of presentation was 4.9 years, with a male to female ratio of 1.8:1. An elevation in the ratio of immunoglobulin G as a percentage of total protein in CSF and an increase in the CSF:serum immunoglobulin G ratio was shown in SSPE patients. The dramatic appearance and high frequency of the disease in PNG might relate to the early age of measles infection encountered in children in this country.
The controversy over the endemicity of human T cell lymphotropic virus type I (HTLV-I) in Melanesia has been settled recently by the isolation of genetically distinct, highly divergent sequence variants of HTLV-I from unrelated inhabitants of Papua New Guinea and the Solomon Islands. Still at issue, however, is the significance of the high frequency of indeterminate HTLV-I Western blots (defined as reactivity to only gag-encoded proteins) among Melanesians. To investigate whether this indeterminate seroreactivity reflects specific reactivity to the Melanesian HTLV-I variants, 27 seroindeterminate Melanesians from Papua New Guinea and the Solomon Islands were studied for evidence of HTLV-I infection. Although antibodies against Melanesian variant-specific env gene products and variant-specific env gene sequences were detected by Western blot analysis and polymerase chain reaction, respectively, in all 11 HTLV-I Western blot-positive Melanesians, none of the 27 seroindeterminate Melanesians had such variant-specific antibodies or HTLV-I proviral sequences. In addition, attempts to isolate HTLV-I from seroindeterminate individuals were unsuccessful. These data indicate that HTLV-I infection is not the cause of the indeterminate Western blot reactivity seen in Melanesia.
Serum samples collected from two groups in the Tari District of Southern Highlands Province were assayed for markers of hepatitis B virus (HBV) infection. 85% of women of childbearing age were found to have markers of HBV infection; 37% were positive for HBV surface antigen (HBsAg), indicative of the chronic carrier state, and 6.6% were positive for HBV e antigen (HBeAg), indicating the presence of actively replicating virus. 75% of women negative for HBsAg were positive for antibody to HBV core antigen (HBcAb), a marker of past infection. A group of children aged 6 to 18 years showed a significantly lower prevalence of markers of infection (66%) but higher rates of HBsAg positivity (46%) and HBeAg positivity (30%). Only 37% of the HBsAg-negative children in this group were positive for HBcAb. The results from this serosurvey suggest that the major route of HBV transmission in this population is horizontal, between older children, though significant transmission also occurs during the neonatal period.
We report the characterization of a variant of human T-lymphotropic virus type I (HTLV-I) isolated from an interleukin 2-dependent, CD8+ T-cell line derived from peripheral blood mononuclear cells of a healthy member of a remote, recently contacted hunter-horticulturalist group (Hagahai) in Madang province of Papua New Guinea. Antigenic characterization of this variant, designated PNG-1, by immunofluorescence, indicated no expression of gag-encoded proteins p19 and p24 (even after incubation with 5-bromo-2'-deoxyuridine), using monoclonal and polyclonal antibodies against HTLV-I gag gene products. Virus-specific proteins of 15, 19, 46, 53, and 61/68 kDa were demonstrated by Western blot analysis, using sera from patients with serologically and/or virologically confirmed HTLV-I myeloneuropathy, sera from HTLV-I-infected rabbits, and antibodies prepared against the C terminus of the major envelope glycoprotein gp46. Restriction endonuclease maps of PNG-1 proviral DNA differed from that of a prototype strain of HTLV-I (MT-2), but, as verified by polymerase chain reaction, PNG-1 was definitely HTLV-I, not HTLV-II. Nucleotide sequencing and further molecular genetic studies of this variant may provide insights into the origin and evolution of HTLV-I.
Ultrasound is of value in the investigation and management of infertility in males and females. Monitoring of follicle growth and follicle aspiration is well accepted and commonly used. Defects of ovulation such as polycystic ovary disease or luteinized unruptured follicle syndrome may be recognized. Problems related to the union of the sperm and ova may also be seen. Obstructing lesions such as endometriosis and fibroids may be investigated by ultrasound. In males the principle use of ultrasound lies in the examination of the seminal vesicles, vas deferens, and ejaculatory ducts to see whether they are intact and unobstructed. Defective sperm motility may be due to varicoceles which are easily detected by the use of ultrasound.
Cohort studies were conducted on 29 pigs from 3 villages in the Highlands of Papua New Guinea. Animals ranged in age from 9 d to 5 m old. Three hundred and twenty nine faecal samples were collected from individual pigs followed over 3 to 6 w periods, and were examined for group A rotavirus antigen by ELISA, and rotaviral genomic RNA by polyacrylamide gel electrophoresis (PAGE). Electron microscopy was also conducted on selected samples. Group A rotavirus was detected in the faeces of 16 pigs with infected individuals coming from all villages. Non-group A rotavirus resembling group C was found in faeces from pigs from 2 villages. All of the group A rotaviruses examined had the same electrophoretype and this was distinct from that of the common type infecting humans in the area at the time of the study. None of the group A positive samples reacted with monoclonal antisera specific for human group A rotaviruses of serotypes 1, 2, 3, 4, or 8. The non-group A rotaviruses also all had identical electrophoretypes. In contrast to previous findings in intensive piggeries, rotavirus infection did not occur in all young pigs and was not limited to young animals under 2 m of age. Infected pigs varied in age from 12 days to 20 weeks of age. This pattern of infection was attributed to the non-intensive husbandry situations in the villages, with less opportunity for transmission to occur than in intensive piggeries.
The sonograms of five neonates with an obstructed urogenital sinus and four with an obstructed cloaca were retrospectively reviewed to determine the sonographic features and the role of pre- and postnatal sonography in the diagnosis and management of hydrocolpos. On pre- and/or postnatal sonograms, the obstructed genital tract was visualized in seven neonates as a large cystic pelvic-abdominal mass, which was the markedly distended urine-filled vagina. One neonate had multiple cystic masses, which resulted from an obstructed duplex genital tract. In one of the neonates with an obstructed cloaca, the anomaly was not diagnosed. The bladder was compressed by the distended vagina and was not visualized in five patients. A vaginal fluid-debris level in six patients was a key finding that distinguished the vagina from the bladder. Obstruction of the urinary tract was an associated feature. An obstructed uterovaginal anomaly with renal dysplasia and oligohydramnios on prenatal sonograms indicates a poor prognosis. Sonography contributes to the diagnosis of an obstructed genital tract and helps define the internal genital anatomy.
The sonograms of 13 patients with obstructed uterovaginal anomalies were reviewed to determine the role of sonography in diagnosis and management. In a retrospective analysis, the authors were able to define the cause of the obstruction and the upper level and length of the obstruction by combining the sonographic findings with those from the physical examination (ie, bulging hymen, blind vaginal pouch, no vaginal depth, normal vagina) or by combining transabdominal sonography with simultaneous digital insertion into the vaginal orifice. When the sonogram demonstrated hematometrocolpos or hematocolpos, the lesion was due to an imperforate hymen (n = 1) or high, middle, or low transverse vaginal septum (n = 7). When the sonogram demonstrated a hematometra, the lesion was due to Mayer-Rokitansky-Küster-Hauser syndrome with functioning uterine anlage(n) (n = 2), cervical dysgenesis (n = 1), and an obstructed uterine horn (n = 2). The presence and patency or absence of the cervix was established. Since the differentiation between a transverse vaginal septum, Mayer-Rokitansky-Küster-Hauser syndrome with active anlagen, and cervical dysgenesis with absent vagina cannot be made clinically, sonography provides important presurgical information.
In the past year, improved ultrasonographic quality has allowed the imaging of more and more subtle anomalies. A major focus of recent discussion, ie, whether the combination of ultrasonographic and maternal blood test results (eg, serum alpha-fetoprotein level) is a satisfactory screening method for commonplace anomalies such as Down's syndrome or spina bifida, is reviewed. Whether these noninvasive tests need to be supplemented by amniocentesis is also discussed, as are ultrasonographic markers for various trisomy syndromes and the association between renal abnormalities and chromosomal defects.
A small-scale trial was carried out at Tari in the Southern Highlands Province of Papua New Guinea to determine the effectiveness of a standard subcutaneous dose of Edmonston-Zagreb measles vaccine (Institute of Immunology, Zagreb) administered to children at less than 8 months of age. Specific antibody levels were measured before and 7-11 weeks after vaccination using an ELISA system. Paired sera from 41 children vaccinated at 4-7 months of age and from 18 children vaccinated routinely at 8-29 months of age were available for comparison. No child 6 months of age or older had detectable maternal antibodies and all of these seroconverted. Post-vaccination titres in 12 children aged 6-7 months were not significantly different from those in older children and 1 year later, post-vaccination titres were still high. In Papua New Guinea, and perhaps in other developing countries, it may prove appropriate and acceptable to vaccinate with Edmonston-Zagreb measles vaccine at 6 months of age without recourse to augmentation of dose from that currently recommended in older children.
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Serum samples collected in 1984 during a malariometric survey of two villages in the East Sepik Province of Papua New Guinea were tested for antibodies to HTLV-I. None of the villagers showed any symptoms suggestive of retrovirus infection. Eighteen of the 186 (9.5%) sera tested at that time were found to be positive. Blood samples were subsequently obtained from fifteen of the eighteen positives and subjected to analysis by enzyme-linked immunosorbent assay (ELISA), radioimmuno assay (RIA), radioimmunoprecipitation assay (RIPA), and Western blot (WB). Fourteen of the fifteen gave a positive ELISA response, but none were unequivocally positive by p 24 RIA. All sera tested were reactive to gag antigens by WB, but gave "indeterminate" results currently accepted criteria. Notably absent from the WB profiles of all of the study subjects was an antibody response to HTLV-I envelope protein gp 46. It is possible that these antibody responses are directed against a variant of HTLV-I or to a novel retrovirus which possesses core antigens similar to those of HTLV-I but has different envelope antigens. Until a virus is isolated, or the viral genome is identified in infected lymphocytes, the possibility remains that the response may be due to factors unrelated to retrovirus infection.
This is a report of a girl infant born with a protuberant abdomen and respiratory distress. A cystic mass was excised from the liver.
Biplanar, transrectal ultrasound guidance was used in the transrectal aspiration of two pelvic abscesses, one recurrent tumor, and one sterile, nonmalignant fluid collection. This method provides an alternative path that allows precise localization for aspiration biopsy of pelvic masses.
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277 patients underwent biplane transrectal ultrasonography. Twenty-two patients (7.9%) showed evidence of one or more intraprostatic cystic lesions. Histologic correlation was available with total prostatectomy specimens in six patients and surgical drainage in two patients. Sonographically, 11 patients showed one, 6 patients two, and 5 patients three or more intraprostatic cystic lesions. The size of the lesions ranged from 2 to 30 mm, and the majority of lesions were located within the central portion of the gland or at the junction of central and peripheral regions of the gland. Histologically, among the eight pathologically confirmed patients the lesions corresponded to cystically dilated, epitheliallined prostatic glands, a reepithelialized cyst related to previous biopsy, a dilated utricle, and two intraprostatic abscesses. The cystic lesions in our series were not associated with carcinoma of the prostate, but represented either a growth phenomenon related to the presence of benign prostatic hypertrophy, inflammatory conditions (abscesses), or anatomical variants (utricle).
Long term total parenteral nutrition (TPN) induces biliary sludge and formation of gallstones. Cholecystectomy is hazardous in these patients because of the underlying medical problems. Therefore, a randomized, double-blind controlled study was designed to test the hypothesis that daily administration of cholecystokinin-octapeptide (CCK-OP) prevents the formation of biliary sludge in humans receiving long term TPN. Adult patients receiving TPN for more than 21 consecutive days were studied. After randomization of 15 patients, the study was concluded because statistical significance was achieved. Eight patients received saline solution (placebo) intravenously and seven received CCK-OP (50 nanograms per kilogram) intravenously over a ten minute period daily. The groups were similar with respect to age, sex, diagnosis, liver function tests, amylase levels, total TPN time and time of study. All of the patients underwent weekly ultrasound studies. Volume and emptying studies of the gallbladder in response to the study drug were performed after one week. None of the patients receiving CCK-OP had sludge whereas five of eight of the patients receiving placebo had sludge (p less than 0.02). The results of emptying studies showed significant contraction of the gallbladder in those in the CCK-OP group but not in the placebo group. These data suggest that CCK-OP given intravenously daily prevents TPN induced stasis and sludge of the gallbladder. We conclude that CCK-OP should be used as routine prophylaxis against biliary sludge and formation of gallstones in patients receiving long term TPN.