Biomedical subjects
N M Williams
Publications and source records attributed to N M Williams.
Variation in susceptibility of ten mouse strains to infection with a strain of Ehrlichia risticii.
Eight inbred strains of mice (A/J, AKR/NCrlBR, BALB/cAnNHsd, C3H/HeJ, C3H/HeNHsd, C57BL/6J, C57BL/10SnJ and CBA/J) and two outbred strains (CF1 and ICR) were inoculated with a strain of Ehrlichia risticii and their relative susceptibility to disease was determined. The strains varied widely in susceptibility, some showing profound illness, with illness being barely detectable in others. Severity of illness was uniform within strains. This study confirmed that the A/J and BALB/cAnNHsd strains were very susceptible to illness, but the C3H/HeJ, CBA/J and the CF1 strains were slightly less susceptible. The C57BL/6J, C57BL/10SnJ, C3H/HeNHsd, AKR/NCrlBR and ICR strains were resistant.
Magnetic resonance imaging of an experimental model of intracranial metastatic disease. A study of lesion detectability.
RATIONALE AND OBJECTIVES: The detectability of brain metastases was evaluated in a rabbit model, with attention to magnetic resonance contrast dose and timing of image acquisition after injection of contrast medium. METHODS: Five New Zealand white rabbits were studied at 1.5 T 6 to 7 days and 11 to 12 days after surgical implantation of an adenocarcinoma tumor nidus. T1- and T2-weighted spin-echo images (0.9 x 0.9 x 2 mm3 voxel size) were obtained before administration of contrast medium. T1-weighted images were repeated 5, 15, and 30 minutes after intravenous injection of 0.1 mmol/kg gadoteridol. At 40 minutes, a supplemental dose of 0.2 mmol/kg (0.3 mmol/kg cumulative dose) was administered, with T1-weighted images repeated at 5, 15, and 30 minutes after the second injection. RESULTS: Six to 7 days after tumor implantation, lesion enhancement (percent change, with normalization to baseline and equilibrium values) was 42 +/- 9% at 5 minutes, 48 +/- 9% at 15 minutes, and 42 +/- 10% at 30 minutes after administration of 0.1 mmol/kg gadoteridol. After administration of 0.3 mmol/kg gadoteridol, lesion enhancement was 111 +/- 13% at 5 minutes, 116 +/- 8% at 15 minutes, and 100% at 30 minutes. On film review, 2 of 5 lesions were not detectable at 6 to 7 days after tumor implantation with 0.1 mmol/kg gadoteridol. Administration of 0.3 mmol/kg gadoteridol provided for lesion identification in each instance. Eleven to 12 days after tumor implantation, one lesion was not detectable with 0.1 mmol/kg gadoteridol. Administration of 0.3 mmol/kg gadoteridol again provided for lesion identification in all cases. Mean lesion enhancement increased from 39 +/- 15% to 104 +/- 10%. CONCLUSIONS: The administration of 0.3 mmol/kg gadoteridol (high dose) compared with 0.1 mmol/kg gadoteridol (conventional dose) improves metastatic lesion detectability in the brain. The lesions identified only at high dose were confirmed by histopathology. Smaller lesions were not detected at a dose of 0.1 mmol/kg.
Retention and attempted mechanical transmission of Ehrlichia risticii by Stomoxys calcitrans.
The ability of adult Stomoxys calcitrans (L.) (Diptera: Muscidae) to retain viable Ehrlichia risticii (Rickettsiaceae), the aetiologic agent of Potomac horse fever (PHF), and mechanically transmit the pathogen from citrated bovine blood artificially infected with E. risticii to susceptible mice was studied. Viable E. risticii were found in the digestive tract of S. calcitrans 3 h after the flies had engorged to repletion on infected blood; however, no E. risticii were detected in flies > or = 2 days after feeding. Subsequently, groups of S. calcitrans were fed for 20 s on infected blood, then fed to repletion on mice 30, 60, 130, 180 or 220 min after having feeding interrupted. Mice displayed no clinical signs of PHF and did not produce anti-E. risticii antibodies when assayed 30 days after S. calcitrans had fed. Although S. calcitrans were able to harbour viable E. risticii for at least 3 h, transmission of the disease agent to susceptible mice during interrupted feeding was not demonstrated under these experimental conditions.
HIV-related deaths from selected infectious diseases among persons without AIDS in New Jersey.
This study sought to quantify HIV-related deaths among persons not classified as having AIDS, in an area where AIDS incidence among injecting drug users (IDUs) is high. Death certificates of persons who were aged 25-44 years at death, died in 1987 in two New Jersey counties, and had certain infectious conditions were compared with names in the AIDS Registry. Hospital and/or Medical Examiner records were reviewed for nonmatching cases. Cases were considered as confirmed HIV infection if there was laboratory evidence of such infection and as suggestive HIV infection if the decedent had oral thrush or a combination of certain other clinical findings were present. Of 412 deaths meeting the above criteria, 165 (40.0%) were in the AIDS Registry. We investigated 205 of the remainder; of these, 7.3% were found to have AIDS, 21.5% had confirmed HIV infection without AIDS, and 15.1% had suggestive HIV infection. This increased the HIV-related mortality in excess of deaths due to AIDS in this age group by 9.2% for confirmed HIV infections and 15.6% for both confirmed and suggestive HIV infections, with deaths among IDUs increasing 12.3% for confirmed HIV infections and 18.9% for both confirmed and suggestive HIV infections. Thus, in addition to AIDS indicator diseases, a variety of other infectious conditions can lead to death in HIV-infected persons, particularly in IDUs; however, the extent of such deaths may be less than previously described.
Characterization of equine oviductal proteins synthesized and released at estrus and at day 4 after ovulation in bred and nonbred mares.
Proteins synthesized and released in vitro by oviducts collected from horse mares during estrus and at day 4 after ovulation for bred and nonbred mares were examined by two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (2-D SDS PAGE) and fluorography. Ampullary and isthmic regions both produced a wide array of nondialyzable proteins in culture. Major proteins or groups of proteins identified according to relative molecular weight (kDa) and apparent isoelectric point (pI) were at 100 kDa, pI 8; 100-200 kDa, pI 6; 150 kDa, pI 4.5; 60-100 kDa, pI 4; and an array of polypeptides at 21-22 kDa, pI 5-6. Oviductal secretory activity, measured by incorporation of radiolabeled amino acids into nondialyzable macromolecules released into incubation medium, was greater (P < .01) for the ampullary than the isthmic oviductal region. No consistent differences were observed in fluorograms between estrus vs. day 4 after ovulation, ampulla vs. isthmus, ipsilateral vs. contralateral to the corpus luteum or largest follicle, oviducts from bred vs. nonbred mares, or mare ages. Dialyzed medium from ampullary and isthmic regions of oviducts was subjected to 1-D or 2-D SDS PAGE followed by western blotting utilizing an antiserum directed against human retinol binding protein (RBP). The family of 21-22 kDA polypeptides was identified as immunoreactive RBP.
Endoscopic transanal resection in the management of patients with sessile rectal adenomas, anastomotic stricture and rectal cancer.
Forty patients underwent 61 endoscopic transanal resections using a urological resectoscope. Preoperative diagnoses were adenoma in 28 patients, carcinoma in seven and benign anastomotic stricture in five. Four patients with adenomas were found to have frank carcinoma. Ablation of 22 of 23 adenomas was achieved, 11 with a single transanal resection. Open operation was required for one patient. Locally advanced rectal malignancy was palliated in five of seven patients. All those with benign anastomotic stricture were cured by a single resection. The median operating time was 25 min, with 11 procedures exceeding 30 min. There were complications in seven cases (six bleeding, one septicaemia). The median hospital stay for the procedure alone was 3.5 days. There were no deaths within 30 days of operation. Endoscopic transanal resection is minimally invasive, quick, safe and effective. Histological surveillance is a major advantage and appears reliable. Low complication rates can be achieved by opting for several 'easy' resections and by restricting use of the procedure to lesions within 15 cm of the anal verge.
The incidence and management of catheter occlusion in patients on home parenteral nutrition.
For patients on Home parenteral nutrition (HPN), catheter-related problems are the major source of morbidity and occlusion of the central venous catheter is one of these. We have managed 17 episodes of catheter occlusion in 10 patients on HPN. The median time from insertion to occlusive episode was 23 months. 10 catheters (59%) were saved by the used of thrombolytics (one by thrombolytics and ethanol) and 7 were replaced. The recent incidence of catheter occlusion in this cohort was one episode per 150 patient-months of HPN (0.08 episodes per year). Patients with Crohns disease appear to be at greater risk of developing catheter occlusion (p = <0.05).
Pseudomonas infection of the catheter exit site successfully managed with topical acetic acid.
A case of recurrent catheter exit site infection with Pseudomonas aeruginosa is presented in a patient receiving home parenteral nutrition. The past episodes were managed by elective catheter replacement following extrusion of the catheter cuff. We describe the successful use of acetic acid to the exit site which resulted in the eradication of the organism and complete resolution of all signs.
Adolescent substance use during pregnancy.
Substance use during pregnancy may be a key mediator of the association between adolescent childbearing and poor newborn outcome. Substance use during pregnancy was evaluated for 50 teens who were consecutive patients at an inner-city university clinic. Although teens reported typical lifetime rates of substance use, self-reports and two urine assays indicated minimal substance use throughout pregnancy. Findings suggest that the adolescents exercised judicious decision making in light of the known health risks of substance use during pregnancy.
In vitro killing of Ehrlichia risticii by activated and immune mouse peritoneal macrophages.
Normal resident murine peritoneal macrophages inoculated in vitro with Ehrlichia risticii readily phagocytized the organism but were unable to suppress ehrlichial replication as determined by indirect fluorescent-antibody staining of the inoculated cells. In contrast, macrophages from Corynebacterium parvum-inoculated and E. risticii-recovered mice rapidly eliminated the ehrlichiae. Macrophages from E. risticii-recovered mice were as effective as the C. parvum-activated cells in phagocytizing and eliminating the organism. Opsonization of E. risticii with homologous antiserum prior to inoculation of macrophage cultures resulted in enhancement of phagocytosis and greater suppression of E. risticii replication in all macrophage groups. These findings indicate that the pathogenesis of E. risticii infection centers on the ability of the organism to enter and replicate within the macrophage with avoidance of macrophage antimicrobial effects. An immune response results in macrophage activation with enhancement of the macrophage's ability to eliminate E. risticii. Opsonization of E. risticii with anti-E. risticii serum renders E. risticii more susceptible to macrophage destruction.
Gluteal compartment syndrome following drug overdose.
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Equine protozoal myelitis in Panamanian horses and isolation of Sarcocystis neurona.
Schizonts of Sarcocystis neurona were identified microscopically in hematoxylin-eosin-stained spinal cord sections from 2 native Panamanian horses that exhibited clinical signs of equine protozoal myelitis (EPM). Spinal cord homogenate from a third Panamanian horse with EPM was inoculated onto monolayers of cultured bovine monocytes (M617). Intracytoplasmic schizonts containing merozoites arranged in rosette forms surrounding a central residual body first were observed 13 wk postinoculation. Parasites divided by endopolygeny and lacked rhoptries. Schizonts from each horse reacted with Sarcocystis cruzi antiserum in an immunohistochemical test.
Immunohistochemical diagnosis of protozoan parasites in lesions of equine protozoal myeloencephalitis.
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Attempted transmission of Ehrlichia risticii (Rickettsiaceae) with Stomoxys calcitrans (Diptera: Muscidae).
Experimental transmission of Ehrlichia risticii, the causal agent of Potomac horse fever, was attempted with adult stable flies, Stomoxys calcitrans, (L.) using two feeding schedules. In schedule A, a set of 140 flies was allowed to feed once on an experimentally infected donor pony and once 24 h later on a recipient pony. A different set of flies was used each day for a 12-d period. In schedule B, 240 flies were allowed to feed once daily for 12 consecutive d on the donor pony followed by five consecutive daily feedings on the recipient pony. E. risticii was isolated from the blood of the experimentally infected pony during the entire fly-feeding schedule. The recipient pony did not develop clinical signs of Potomac horse fever and remained seronegative to E. risticii up to 60 d after the last stable fly feeding. Mice injected intraperitoneally with emulsions of schedule A and B stable flies were seronegative for E. risticii 30 d after inoculation, and ehrlichial organisms were not demonstrated in impression smears from the digestive tracts of the flies. The stable fly did not transmit E. risticii under these experimental conditions.
The effect of a school entry law on mumps activity in a school district.
Sixty-three cases of clinical mumps occurring in a New Jersey school district presented an opportunity to determine compliance with the state's 1978 mumps "new entrants" school immunization law, investigate the effect of the law on the pattern of the outbreak, estimate the efficacy of mumps vaccine, and quantitate the economic impact of the outbreak. Only students in kindergarten (K) through grade 5 would have been affected by the immunization law. Students in the sixth grade were nearly seven times more likely to develop mumps than students in grades K through 5. The observed differences between the sixth graders and those in grades K through 5 most likely reflect the fact that sixth graders were not covered by the school law. Vaccine efficacy was estimated to be 91% (95% confidence interval = 77% to 93%). The total direct cost of the outbreak was $10,937 (clinic costs plus total cost to households). This outbreak demonstrates the significant impact of appropriate school vaccination laws on limiting the morbidity and economic and social costs of mumps.
Transmission of measles in medical settings. 1980 through 1984.
For the five-year period 1980 through 1984, a total of 241 persons with measles in 30 states were identified as probably having acquired their infection in a medical facility. The proportion of all measles cases acquired in medical settings increased from 0.7% for 1980 through 1982 to 2.9% for 1983 and 1984. Seventy-six percent of cases were found in patients or visitors, and 24% in personnel at the medical facility where transmission occurred. The highest proportion of cases occurred in children less than 5 years of age (54.3%), followed by persons 25 to 29 years of age (14.7%). Of spread (50.0%) and patient-to-staff spread (36.7%) were most common. Medical personnel rarely transmitted disease to others. More attention needs to be given to methods of preventing spread of measles in medical facilities, such as isolation precautions, postexposure prohylaxis of potential contacts (vaccination or immune globulin), and ensuring that medical personnel are immune to measles.
Fetal risk associated with rubella vaccine: implications for vaccination of susceptible women.
The Centers for Disease Control has maintained a register of women who received rubella vaccine within three months before or three months after conception to follow prospectively the outcome of pregnancy and to quantitate the risks to the fetus from the vaccine virus. The data indicate that rubella vaccine can cross the placenta and rarely can infect the fetus. However, no abnormalities consistent with congenital rubella syndrome have been noted in 144 infants whose susceptible mothers received the RA 27/3 rubella vaccine, the only vaccine available in the United States since 1979. Although the observed risk of defects consistent with congenital rubella syndrome is zero, there is a statistical theoretic risk of a congenital rubella syndrome-like defect; the maximum theoretic risk is 2.6%. These findings indicate that vaccination of nonpregnant postpubertal women who lack either serologic proof of immunity or a written record of vaccination on or after the first birthday can be done safely and effectively. Whereas congenital rubella infection will disappear from the United States as vaccinated children enter the childbearing years, if these practices are followed elimination of congenital rubella infection will be hastened.