Search PubMed⌕ Search

Biomedical subjects

J L Hubbard

Publications and source records attributed to J L Hubbard.

34 records · Page 2Linked to original sources
PubMed1991

Enzyme immunoassay for detection of antibodies against eastern equine encephalomyelitis virus in sentinel chickens.

We developed an enzyme immunoassay (EIA) for the detection of immunoglobulin M (IgM) and IgG subclass antibodies directed against eastern equine encephalomyelitis (EEE) virus in chickens. The assays were compared with the serum plaque reduction neutralization test (PRNT) and the hemagglutination inhibition (HI) test for ability to detect antibodies against EEE virus in laboratory-infected birds. No cross-reactivity was detected in serum from chickens inoculated with St. Louis encephalitis or Highlands J virus. The interval after infection when EEE virus-specific antibodies were first detected by IgM and IgG EIAs was found to be similar to that determined by the PRNT and HI tests: 2 to 4 days. The IgG EIA, PRNT, and HI test detected antibodies to EEE virus for at least 27 to 30 days after inoculation. In contrast, serum from five of seven chickens did not contain detectable IgM 30 days after infection. Similarly, in all three naturally infected sentinel chickens from Maryland, IgM class antibody was undetectable 1 to 5 weeks after IgM was initially detected. EIAs provide simple and rapid alternatives to traditional tests for monitoring EEE virus infections in sentinel chicken flocks. Moreover, the IgM EIA provides a means to separate recently infected chickens from those infected greater than or equal to 1 month earlier.

Animals↗
PubMed1990

Cancer of the endometrium.

Cancer of the endometrium is the most common and curable gynecologic malignancy. It has a most easily recognizable symptom in its usual presentation as postmenopausal bleeding. Treatment may vary considerably based on prognostic factors and may include surgery, radiotherapy, hormonal manipulation, or cytotoxic chemotherapy. Rehabilitation is the focus of nursing intervention and is initiated at the time of the cancer diagnosis. The continued effort by investigators to define intermediate and high-risk populations and, thus, appropriate adjuvant treatment will continue to reduce mortality from endometrial carcinoma.

Adenocarcinoma↗
PubMed1989

Renal and hepatic toxicity of N-arylsuccinimides in Fischer 344 rats.

The role of aromaticity in the nephrotoxic potential of N-arylsuccinimides was studied in male Fischer 344 rats. Rats were administered a single intraperitoneal (i.p.) injection of an N-arylsuccinimide derivative (0.4 or 1.0 mmol/kg) or sesame oil (2.5 ml/kg), and the renal function monitored at 24 and 48 h. The parent compound in this series, N-phenylsuccinimide (NPS), had previously been shown to induce only minimal renal effects, having no effect on urine volume, blood urea nitrogen concentration, kidney weight, p-aminohippurate accumulation or renal morphology. Only an increase in tetraethylammonium uptake has been observed following NPS administration to rats. These effects were not enhanced by reducing aromaticity (N-cyclohexylsuccinimide (NCS]. Compounds with increased aromaticity N-(1-naphthyl)succinimide (NNS), N-(1-anthracenyl)succinimide (1-NAS) and N-(9-anthracenyl)succinimide (9-NAS)--also only weakly affected renal function. However, NNS (1.0 mmol/kg) and, to a lesser degree, 9-NAS (1.0 mmol/kg) proved to be hepatotoxins. Liver damage was most pronounced near central vein regions of the lobule and least evident around periportal sites. Damaged liver tissue exhibited unusually large deposits of connective tissue and hypertrophied hepatocytes with numerous vacuoles in their cytoplasm. Therefore, derivatives of NPS with increased or decreased aromaticity relative to the parent compound do not exhibit the ability to induce moderate or marked nephrotoxicity. However, increasing aromaticity did produce the derivatives NNS and 9-NAS, which are hepatotoxins. These compounds represent the first members in this series of compounds to induce acute hepatotoxicity.

Animals↗
PubMed1989

Effects of triturated Culiseta melanura (Diptera: Culicidae) on recovery of eastern equine encephalomyelitis virus.

Experiments were done to determine the effect, if any, of larval and adult Culiseta melanura (Coquillett) suspensions on the recovery of eastern equine encephalomyelitis (EEE) virus in baby hamster kidney (BHK) and Vero cell cultures. Although triturated pools of this mosquito reduced the titer of EEE virus added to suspensions, suspensions prepared from as many as 100 Cs. melanura larvae or adults did not reduce titers of virus to undetectable levels. Similarly, the titer of EEE virus in orally infected female Cs. melanura remained detectable when a single infected mosquito was triturated in a pool with 99 uninfected mosquitoes. These results show that in BHK or Vero cell culture assay systems, triturated Cs. melanura do not completely prevent the detection of EEE virus. The results therefore indicate that mosquito suspensions would not interfere with the isolation of virus from field-collected mosquitoes. This conclusion suggests that mosquito suspensions were not a factor in previous studies that were unsuccessful at detecting transovarial transmission of EEE virus by Cs. melanura.

Alphavirus↗
PubMed1989

Adult cerebellar medulloblastomas: the pathological, radiographic, and clinical disease spectrum.

The records of 34 patients over 16 years of age with cerebellar medulloblastoma were retrospectively reviewed. All patients were treated by surgery, and all surviving patients were given radiation therapy. The imaging characteristics of this rare entity were evaluated with regard to the tumor location in the cerebellum, and the prognostic effects of histological characteristics such as neuronal or glial differentiation and the presence of desmoplasia were investigated. Neither histological parameters nor tumor location (median, paramedian, or lateral cerebellar) affected patient survival. The desmoplastic variant was encountered in 38% of these adult medulloblastomas and occurred in all three cerebellar locations. The degree of surgical resection did not have a major effect on long-term survival; long-term survival was possible even in patients who had received only a biopsy. The extent of initial radiation therapy was positively correlated with recurrence-free survival; full neuraxis irradiation was associated with a 13% incidence of delayed spinal metastases, whereas 75% of patients treated with irradiation of only the posterior fossa and/or the whole brain developed spinal deposits. A similar local recurrence rate (12.5%) was noted in both irradiation groups. Chemotherapy resulted in palliation in some patients with metastatic disease.

Adolescent↗
PubMed1987

Trapped fourth ventricle in an adult: radiographic findings and surgical treatment.

Trapped fourth ventricle is a rare entity that has most often been reported mainly in children as a late complication of lateral ventricle shunting. We report a case in a previously normal adult who developed symptoms several months after bacterial meningitis. Unique radiographic and surgical findings are discussed, and recommendations are made for the classification and treatment of fourth ventricular enlargement.

Cerebral Ventricles↗
PubMed1987

Prolactin-secreting adenomas: the preoperative response to bromocriptine treatment and surgical outcome.

Controversy exists regarding the effects of bromocriptine on the success of transsphenoidal surgery for patients with prolactinomas. Various studies on this drug have reported adverse effects, improvement, and no effect upon the subsequent surgical outcome. The authors have retrospectively reviewed the case histories of 55 patients with immunocytochemically confirmed prolactin-secreting pituitary adenomas operated on by a transsphenoidal approach between 1981 and 1985. All patients had received bromocriptine in a variety of doses and for variable durations prior to surgery. Thirty-nine patients were women and 16 were men, with an age range of 8 to 72 years. Basal prolactin levels prior to bromocriptine treatment ranged from 38 to 100 ng/ml in 11 patients, from 101 to 200 ng/ml in 12, and greater than 200 ng/ml in 29. The "cure" rates were 54%, 58%, and 38%, respectively. Thirty-one patients had microadenomas, with a postoperative cure rate of 68%; 12 had diffuse expansive adenomas, with a 17% cure rate; and 12 had grossly invasive tumors, with a 17% cure rate. A response to preoperative bromocriptine therapy was defined as a return of the basal prolactin level to normal: 18 patients were responders and 29 were hyporesponders; in eight the data were not available. The postoperative cure rate was 50% for the responders and 31% for the hyporesponders. Taking into account the distribution of tumor type, there was no actual difference in outcome between the responder and the hyporesponder groups. The total bromocriptine dose received preoperatively was nearly identical for all groups. No significant differences in the frequency or extent of fibrosis, calcification, or prolactin immunoreactivity were observed in the 55 patients when compared with 26 control prolactinomas not treated with bromocriptine. It is concluded that short-term bromocriptine treatment does not adversely affect surgical outcome in any of the prolactin-secreting adenoma groups, nor does response or lack of response to bromocriptine predict surgical outcome.

Adenoma↗
PubMed1985

Spontaneous cerebrospinal fluid rhinorrhea: evolving concepts in diagnosis and surgical management based on the Mayo Clinic experience from 1970 through 1981.

Spontaneous cerebrospinal fluid (CSF) rhinorrhea, occurring in the absence of recent trauma, is a distinct clinical entity that can be difficult to diagnose and treat. The case records of 28 patients with this entity were reviewed retrospectively. Pertinent historical data and the results of radiographic evaluation are discussed. The patients were classified into one of three major etiological categories: congenital anomaly, delayed posttraumatic, and tumor groups. The fistulas causing the rhinorrhea were approached extracranially or intracranially, depending on the suspected cause and location. A cure was obtained in 22 of the 27 patients surgically treated (81%). Seventeen patients were cured by a single operation, 5 were cured after multiple operations, and 5 continued to leak despite surgical treatment. Three of the 5 patients who were surgical failures had intracranial tumors, and 2 of them died from complications of persistent fistulas. With the use of a multidisciplinary team approach, an extracranial operation (transethmoidal or transsphenoidal) to repair a spontaneous CSF leak offers a high success rate and is associated with minimal morbidity in appropriately selected patients.

Adolescent↗
PubMed1983

Failure of naloxone to affect focal incomplete cerebral ischemia and collateral blood flow in cats.

Focal incomplete cerebral ischemia was created in 20 adult cats by retro-orbital middle cerebral artery (MCA) occlusion under halothane anesthesia. Arterial blood flow (CBF), bilateral electroencephalographic (EEG) recordings, and systemic arterial blood pressure (SABP) were monitored for the 1st hour of occlusion. Ten animals were treated with 10 mg/kg of naloxone within 10 minutes of MCA clipping, followed by a continuous infusion of naloxone at 2 mg/kg/hr for the duration of the occlusion (8 hours). Ten animals were treated in a similar fashion with physiological saline (control). Blood flow was restored after 8 hours. The brains were examined at the time of death or 7 days after the occlusion period. There was no difference between the two groups regarding cerebral infarction size or distribution, neurological outcome, SABP, PaCO2, or CBF. Minor changes in EEG amplitude observed in the naloxone-treated group appear to represent interaction of the drug with halothane after prolonged administration. The authors conclude that naloxone did not modify the outcome of focal cerebral ischemia in the cat.

Animals↗
PubMed1973

The effect of exercise on lactate metabolism.

1. An I.V. injection of 5 muc [U-(14)C]sodium L(+)-lactate was given to four subjects at rest and again 10 min after beginning a 40-50 min period of heavy exercise at an estimated 62-72% of their maximum aerobic power (V(O) (2) max.). Both blood lactate concentration and V(O) (2) remained relatively constant after the first few minutes of exercise.2. In all subjects both at rest and during exercise blood lactate and total radioactivity were measured at frequent intervals after injection of [(14)C]lactate. Timed expired gas collections were made and the quantity of (14)CO(2) present in each collection measured. In two subjects the specific activity of lactate and of glucose isolated from blood was also measured.3. It was found that during 30 min of exercise 35-68% of the administered [(14)C]lactate was recovered as (14)CO(2) in the expired gas, whereas at rest only 3-7% was recovered in the same period.4. After injection of [(14)C]lactate the blood (14)C concentration and the specific activity of the blood lactate declined very rapidly. This decline was more rapid during exercise than at rest.5. In the two subjects in whom it was measured the specific activity of blood glucose was lower during exercise than at rest.6. These results show that both at rest and during heavy exercise, lactate is removed from the blood and metabolized, and that during exercise this metabolism is much more rapid.7. In the light of these findings the sustained blood lactate concentration observed in these experiments is regarded as representing a dynamic equilibrium between the production and metabolism of lactate during exercise. The results give no support to the hypothesis that lactate is produced only during the first few minutes of submaximal work.

Blood Glucose↗
PubMedDate not supplied

Acute renal and hepatic effects induced by 3-haloanilines in the Fischer 344 rat.

Haloanilines are commonly used as chemical intermediates in the manufacture of a wide range of products. The purpose of this study was to examine the in vivo nephrotoxic and hepatotoxic potentials of the 3-haloanilines. The in vitro effects of the 3-haloanilines on renal function were also examined. In the in vivo experiments, male Fischer 344 rats (four rats/group) were administered a single intraperitoneal (i.p.) injection of an aniline hydrochloride (1.0 or 1.25 mmol kg-1) or vehicle. Renal and hepatic function were monitored at 24 and/or 48 h post-treatment. None of the 3-haloanilines were potent nephrotoxicants at either dose level. The greatest effects on renal function were observed following administration of 3-chloroaniline at a dose of 1.25 mmol kg-1 (oliguria, glucosuria, hematuria, decreased p-aminohippurate accumulation by renal cortical slices and increased blood urea nitrogen concentration). 3-Chloroaniline also was the only aniline compound to increase plasma ALT/GPT activity at 48 h. In the in vitro experiments, the ability of an aniline (10(-5) - 10(-3) M) to decrease organic ion accumulation in renal cortical slices from untreated rats was examined. The decreasing order of in vitro nephrotoxic potential was 3-iodoaniline > 3-bromoaniline > 3-chloroaniline > aniline > 3-fluoroaniline. These results indicate that the 3-haloanilines are not potent nephrotoxicants or hepatotoxicants at sublethal doses. In addition, the reasons why the 3-haloanilines have different orders of nephrotoxic potential in vivo and in vitro are not clear at this time.

Aniline Compounds↗