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Biomedical subjects

J J Phillips

Publications and source records attributed to J J Phillips.

At least 19 recordsLinked to original sources
PubMed1998

TurboPrep II: an inexpensive, high-throughput plasmid template preparation protocol.

In an effort to reduce plasmid template preparation costs for large-scale genomic sequencing projects, a boiling minipreparation protocol has been developed that enables a single individual to easily prepare 768 sequence-quality templates in 8 h, without automation. The maximum throughput for one individual using one centrifuge in the manual configuration is 1920 templates in about 8 h. The most time-consuming manual steps of this method involve pipetting, which can be automated, resulting in a significant increase in throughput and about a 60% increase in yield. This method in the fully manual configuration yields sufficient double-stranded template for two sets of cycle sequencing reactions, membrane spotting for hybridization analysis and host cell transformation for the recovery of the original recombinant. The current materials cost per template using this method is less than twenty cents. The quality of the sequence generated has been evaluated by manual 35S radioactive cycle sequencing. Initial results have shown templates prepared by this method to yield greater than 300 bp of readable sequence when the radioactively labeled products were resolved on 6% modified denaturing polyacrylamide gels.

DNA, Recombinant↗
PubMed1996

Adrenal gland volume in major depression: relationship to basal and stimulated pituitary-adrenal cortical axis function.

We measured adrenal gland volume and both baseline and stimulated pituitary and adrenal cortical hormones in 35 unmedicated, major depressives and 35 individually matched normal control subjects. Mean adrenal volume in the depressives was significantly larger, by about 38%, than the adrenal volume of their matched controls. Basal plasma adrenocorticotropic hormone (ACTH)1-39 was significantly lower, and basal plasma cortisol was significantly higher, in the patients. In contrast, basal plasma ACTH determined by radioimmunoassay (RIA) was not significantly different between the two groups. The ACTH response to ovine corticotropin-releasing hormone (oCRH), whether measured specifically as ACTH1-39 or by the less-specific RIA, was highly significantly lower in the depressives than in the controls. However, neither the cortisol response to oCRH nor its response to low-dose ACTH 1-24 differed significantly between groups. In both groups of subjects, correlations between adrenal gland volume and all the hormone measures were low, and none represented more than 4% shared variance. In the patients, adrenal volume did not correlate significantly with duration of the present episode, lifetime number of episodes, melancholic subtype, Hamilton Depression Scale total score, or the Hamilton suicidality item. However, adrenal volume was significantly positively related to the somatization factor of the Hamilton scale, which was almost totally accounted for by the specific items of somatic symptoms and somatic anxiety.

Adolescent↗
PubMed1996

Cryopreservation of rooster sperm using methyl cellulose.

Experiments were designed to determine when, during the cryopreservation process, sperm lose fertilizing capacity and whether the cryoprotectant, methyl cellulose (MC), could be used in combination with glycerol to cryopreserve sperm and remain in the inseminate without reducing fertility. Semen diluted in Minnesota Avian extender (MNA) and inseminated immediately had greater fertility (75%) than semen processed for cryopreservation (12 to 60%). The largest decreases in fertility were due to addition of glycerol to sperm and to cryopreservation. In another experiment, fertility of inseminates containing 0, 1, and 2% glycerol were 82, 29, and 21%, respectively, for eggs collected 2 to 5 d after insemination. When 0.5% MC was added to the same three treatments, fertility rates were 88, 63, and 69%, respectively. Semen cryopreserved in MNA containing 9% glycerol; MC + 3% glycerol; MC + 4% glycerol; MC + 9% glycerol; or 9% glycerol with the cryoprotectant removed post-thaw by dilution and subsequent centrifugation exhibited 59, 30, 35, 60, and 69% viable cells, respectively; and 65, 38, 46, 69, and 65% motile sperm, respectively. Sperm cryopreserved with MC and either 4 or 9% glycerol exhibited similar numbers of sperm binding to chicken perivitelline layers in vitro as did fresh sperm, whereas sperm frozen with MC and 3% glycerol bound oocytes with only 31% efficiency (P < 0.05). The extent to which cryopreserved sperm penetrated the perivitelline layer in vitro was independent of glycerol concentration, but was four times more efficient than that of fresh sperm (P < 0.05). The fertility rates of fresh semen, semen frozen in 9% glycerol with the cryoprotectant removed after thawing, and semen frozen in MC with either 3 or 4% glycerol were 87.4, 27.6, 0.8, and 0.5%, respectively (P < 0.05). The MC reduces the contraceptive effects of glycerol when inseminated with fresh sperm, but does not maintain fertilizing capacity in frozen-thawed sperm when used in combination with 3 or 4% glycerol.

Animals↗
PubMed1995

Adrenal gland volume in major depression. Increase during the depressive episode and decrease with successful treatment.

BACKGROUND: Hyperactivity of the pituitary-adrenocortical axis is the most prominent neuroendocrine abnormality in major depression. It is state-related, returning to normal with resolution of the depressive episode. Adrenal gland enlargement also has been reported in patients with major depression and has been hypothesized as an index of cumulative lifetime depression. However, whether or not adrenal enlargement decreases with successful treatment of depression has not yet been studied, to our knowledge. We, therefore, determined adrenal gland volume in patients with major depression before and after treatment and in matched normal controls, and compared adrenal size with functional indexes of pituitary-adrenocortical activity. METHODS: Adrenal volumes were measured by magnetic resonance imaging in nine adult and two adolescent patients with major depression during their illness and during full remission when medication had been stopped for at least 1 month, and in nine adult and two adolescent normal control subjects individually matched to the patients. Basal, 4 to 7 PM plasma corticotropin 1-39 and cortisol levels, and corticotropin 1-39 and cortisol responses to administration of ovine corticorelin and lowdose cosyntropin also were measured. RESULTS: Mean adrenal gland volume was significantly larger, by about 70% in the patients while depressed than after successful treatment, and it also was significantly larger, again by about 70%, than the mean adrenal gland volume of their matched controls. After treatment, the mean adrenal volume of the patients decreased and was no longer significantly different from that of their controls at baseline. The magnitude of the decrease was significantly positively correlated with the duration of the depressive episode. Basal, late-afternoon plasma corticotropin 1-39 levels were significantly lower in the patients while depressed than in their matched controls, but basal plasma cortisol levels did not differ significantly among the three groups, nor did the corticotropin 1-39 and cortisol responses to corticorelin or the cortisol response to cosyntropin. Correlations between adrenal gland volume and basal corticotropin and cortisol levels, and the corticotropin and cortisol responses to hormone challenge, were not consistently in the expected direction in any of the three groups of subjects. CONCLUSIONS: Adrenal gland enlargement occurring during an episode of major depression appears to be state-dependent, in that it reverts to the normal size range during remission after treatment. It thus does not appear to be an index of cumulative lifetime depression. The lack of a discernible relationship between adrenal volume and pituitary-adrenocortical activity remains to be explained and might be related to noncorticotropin influences on the adrenal gland, including other tropic hormones and/or neural mechanisms.

Adolescent↗
PubMed1994

Bond strength of six dentinal adhesives.

This study compared the shear bond strengths on dentine of five dentine adhesives against Scotchbond 2 as a control. Dentine specimens from 225 extracted human permanent molar teeth were used in a matched-pair design, such that 45 tooth sides were treated along with the matching control for each of the five test materials. Shear bond strength testing was conducted 24 h after the completion of each specimen. Results showed that mean force (MPa) for the materials were: XR Bond, 17.1 +/- 5.1; Scotchbond Multi-Purpose, 15.9 +/- 6.5; Syntac, 13.5 +/- 8.6; All-Bond 2, 6.2 +/- 4.1; Scotchbond 2 (control composite score), 4.9 +/- 3.0; Denthesive, 3.4 +/- 1.7. Matched pair t-test comparisons with Scotchbond 2 control were: XR Bond, P = 0.0005; Scotchbond Multi-Purpose, P = 0.0005; Syntac, P = 0.0005; All-Bond 2, P = 0.0368; Denthesive, P = 0.005. Analysis of variance determined a statistically significant difference (P = 0.05) between the means of the bond strengths, which fell into four groups: Group A, XR Bond and Scotchbond Multi-Purpose; Group B, Syntac; Group C, All-Bond 2 and Scotchbond 2; Group D, Scotchbond 2 and Denthesive. In Group C, there was no significant difference between Scotchbond 2 and All-Bond 2. In Group D there was no significant difference between Scotchbond 2 and Denthesive, however, there was significant difference between All-Bond 2 and Denthesive. It was concluded that XR Bond and Scotchbond Multi-Purpose had significantly better shear bond strength than the other dentine adhesives.

Analysis of Variance↗
PubMed1993

Positive bowel contrast agent for MR imaging of the abdomen: phase II and III clinical trials.

PURPOSE: To evaluate the efficacy and safety of two dose levels of an orally administered ferric ammonium citrate-based contrast agent for bowel enhancement on T1-weighted spin-echo magnetic resonance (MR) images in 222 patients with known or suspected abnormality of the upper abdomen. MATERIALS AND METHODS: Adverse reactions were graded for intensity, frequency, duration, and relationship to the contrast agent. Twelve unblinded readers compared enhanced with unenhanced images; all MR images were evaluated by two independent offsite radiologists in a blinded review. RESULTS: No statistically significant changes in mean vital signs or laboratory values were seen. Forty-eight of 220 patients (22%) reported minor side effects. The readers found increased intraluminal signal intensity and improved contrast enhancement of the gastrointestinal tract and distention and improved signal homogeneity in 101-107 cases (89%-98%) after ingestion; the blinded reviewers' findings were similar. CONCLUSION: The contrast agent provided new or additional radiologic information in 142 patients (64%), specific additional information in a detected abnormality in 46 of 142 patients (32%), and information that changed diagnosis, management, or surgical approach in 22 of 142 patients (15%).

Abdomen↗
PubMed1993

MR mammographic localization. Work in progress.

The authors present phantom test results for a stereotaxic device that may permit simple, rapid, and accurate needle biopsy and localization of breast lesions detected at contrast material-enhanced magnetic resonance (MR) mammography. The mechanical accuracy of this prototype MR breast localizer is approximately plus or minus 3.5 mm at 5 cm.

Biopsy, Needle↗
PubMed1992

Influence of the mode of preparation on the long-term efficacy of homologous costal cartilage implants.

Devitalized homologous costal cartilage is widely employed as an implant in the management of the saddle nose. The tissue response induced by the implant is a combination of enveloping fibrosis and implant resorption, which will probably, ultimately, be complete. We have studied the balance between resorption and fibrosis, following different modes of cartilage preparation, in the mouse. Homologous costal cartilage was devitalized by four common methods--irradiation, formalin, glutaraldehyde and alcohol. Segments of this cartilage were inserted at separate sites in the subcutaneous plain of the tail. These implants were harvested after one year for histology. Variations in the mode of cartilage devitalization, while inducing variations in the degree of the tissue response, did not influence the balance between fibrosis and resorption. Thus the long term maintenance of tissue bulk following homologous cartilage implantation is not influenced by the mode of preparation. Evidence suggests that the ultimate cosmetic results of autologous and homologous costal cartilage implantation would be much the same, and the use of homologous cartilage must be justified on other grounds.

Animals↗
PubMed1991

MR and CT imaging of ethanol-treated liver tumors in an animal model.

To characterize the radiographic appearance of liver lesions over time following ethanol injection, seven New Zealand white rabbits underwent surgical implantation of small fragments of VX-2 carcinoma within the liver. Upon reaching 1 cm in diameter, a tumor nodule was directly injected with absolute ethanol. Another nodule in the same animal was injected with saline as a control. Imaging was performed 6-24 days after the injections by high resolution CT and MRI, and correlation obtained with the pathologic specimens. Long TR spin-echo MR sequences were found to characterize the ethanol-treated regions of liver most accurately. Liver tissue infarcted by alcohol could be differentiated from tumor and necrosis by virtue of its short T2 relaxation value. There were no distinguishing features by other imaging techniques between the ethanol-treated and control tumor nodules. Peripheral contrast enhancement was demonstrated in both, corresponding to fibrous tissue around the ethanol-injected regions, and to viable tumor in the case of controls.

Animals↗
PubMed1991

Adrenal gland volume determination by computed tomography and magnetic resonance imaging in normal subjects.

To compare the usefulness of computed tomography (CT) and magnetic resonance imaging (MRI) for the quantitative determination of adrenal gland size in human subjects, adrenal gland volumes were determined by both techniques in five female and five male, normal, nonstressed adult volunteers. Mean left and right adrenal volumes were slightly larger by CT, and the left adrenal volume was slightly larger than the right by both imaging techniques. Volume determinations by CT and MRI correlated +0.85 and +0.82 for the left and right glands, respectively. Body surface area was highly correlated, and sex moderately correlated, with left and right adrenal volumes by both techniques. Both CT and MRI somewhat overestimated the known volumes of a set of phantoms, CT by an average of 42% and MRI by an average of 20%. The results of this initial study suggest that MRI holds promise as a technique for in vivo adrenal gland measurements, and that the influence of both body surface area and sex should be considered in comparative studies of adrenal size.

Adrenal Glands↗
PubMed1991

Magnetic resonance imaging of pediatric head and neck cystic hygromas.

We retrospectively reviewed the magnetic resonance imaging (MRI) findings of eight pathologically proved cystic hygromas in seven pediatric patients. All lesions showed multiple cysts, best depicted on T2-weighted images (T2WI). Six of the eight lesions had well-defined borders. Fluid-fluid levels were visualized in seven of eight lesions, with very high signal intensity of the upper fluid on T2WI. On T1-weighted images, all lesions showed a mean signal intensity greater than that of muscle (1.6 times) and cerebrospinal fluid (CSF; 4.04 times) and less than that of fat (0.5 times). On T2WI, the mean signal intensity was greater than that of CSF (1.8 times), muscle (9.45 times), and fat (2.54 times). Chemical analysis of the cystic fluid from one lesion showed high lipid content and hemorrhage, consistent with the preoperative and in vitro MRI findings on the fluid from the same patient. Lesion anatomic distribution showed frequent posterior triangle involvement; however, the epicenter of 75% of the lesions was outside the posterior triangle. Only one lesion had involvement limited to the posterior triangle. There was equal distribution of right and left sides and no midline lesion. Seven lesions displaced the sternocleidomastoid muscle laterally, whereas one displaced it posteriorly, with no evidence of muscle infiltration. Only those patients with submucosal involvement (two of seven) had respiratory symptoms. Gadolinium provided no additional information with regard to diagnosis or extent of involvement. Our experience indicates that MRI is useful in the diagnosis and treatment planning of cystic hygromas.

Child, Preschool↗
PubMed1990

Acute infective airway obstruction associated with subglottic stenosis.

Pre-existing subglottic stenosis in a 22-month-old child with laryngotracheobronchitis resulted in failure to intubate the trachea on the intensive therapy unit. Tracheostomy was necessary in the operating theatre to secure the airway. The implications for safe management are discussed.

Acute Disease↗
PubMed1988

Visual contrast enhancement with a patterned overlay.

A dot-screen pattern was devised and superimposed on computed tomography images to improve contrast at a viewbox. The phenomenon is believed to be probably related to lateral inhibition. To evaluate its usefulness, the device was used on 12 images (eight showed metastatic liver lesions, and four were normal); each image was viewed without the device by ten observers. Three control images were viewed a second time without the device. The remaining nine images were viewed a second time with the device. The overlay improved diagnostic performance in nine observers. Sensitivity improved by 12%, and confidence in true-positive findings increased by 41.6%. Forty-five percent of false-negative findings were converted to true positive with the use of the overlay.

Humans↗
PubMedDate not supplied

MR imaging of Ho:YAG laser diskectomy with histologic correlation.

Twelve cadaveric vertebral specimens were imaged after holmium yttrium aluminum garnet (Ho:YAG) laser diskectomy to determine the usefulness of magnetic resonance (MR) imaging in evaluating treatment outcome. The Ho:YAG laser was operated at 1.0-2.0 J per pulse, 5 Hz, and 250-microseconds pulse width. The total energy varied between 600 and 2,700 J. Two distinct patterns emerged on MR images. Tissue ablation at higher power (1.5 and 2.0 J per pulse) produced discrete signal voids that correlated with areas of laser-induced ablation identified at gross inspection. More subtle changes, characterized by a high-signal-intensity ring, were seen in the specimens lased at 1.0 J per pulse. The latter appearance corresponded to incomplete vaporization of diskal tissue, a broader zone of minimal thermal injury, and sparing of adjacent vertebral endplates. Total mass loss did not appear to be affected by the choice of power setting (1.0 vs 1.5 J per pulse), with total laser energy held constant.

Adult↗
PubMedDate not supplied

Motion artifact suppression technique (MAST) for MR imaging.

A technique has been developed that significantly improves the image resolution and reduces motion artifacts in conventional two-dimensional Fourier transform and three-dimensional Fourier transform magnetic resonance imaging sequences. Modifications on the gradient waveforms completely refocus the transverse magnetization at the echo time, regardless of the motion occurring between the time of the 90 degrees radiofrequency excitation and the echo time (within-view). This accomplishes suppression of motion artifacts and regains the signal from flowing blood and CSF. Images of the head, abdomen, chest, and spine are reproduced which show the increase in signal and anatomical detail that would otherwise be degraded and lost in artifact noise. This technique has reduced the practical difficulty of obtaining clinically diagnostic T2-weighted abdominal images. It also has allowed diagnostic quality T1- and T2-weighted images to be obtained with one acquisition per view, thus reducing the total scan time.

Brain Stem↗
PubMedDate not supplied

Perirenal hemangioendothelioma in a newborn: sonograph and MR findings.

This is a case report of perirenal hemangioendothelioma in a newborn and discussion of lesions in the perirenal space in newborns. The findings in this case, high echogenicity on sonographic images and high signal intensity on T2-weighted spin echo magnetic resonance images, mimic those described for hemangiomas in other locations.

Hemangioendothelioma↗