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Biomedical subjects

J Hale

Publications and source records attributed to J Hale.

At least 55 records · Page 3Linked to original sources
PubMed1995

Susceptibilities of Neisseria gonorrhoeae to the glycylcyclines.

To assess the activities of two glycylcyclines, N,N-dimethylglycylamido (DMG) derivatives of minocycline (MINO) and 6-demethyl-6-deoxytetracycline (DMDOT), 203 gonococcal isolates recovered at six sexually transmitted disease clinics in the western United States were evaluated. Antimicrobial susceptibilities to tetracycline HCl, doxycycline, MINO, DMG-DMDOT, and DMG-MINO were determined by agar dilution tests. DMG-DMDOT and DMG-MINO were more active than tetracycline HCl, doxycycline, or MINO regardless of the presence of Tet M or of chromosomal mutations mediating tetracycline resistance (P < 0.001).

Gonorrhea↗
PubMed1993

Relations between attentional deficits and clinical symptoms in schizophrenic outpatients.

Information-processing impairments have been suggested to be at the core of the cognitive deficits observed in schizophrenia and may represent preclinical markers of genetic vulnerability to the illness. Of particular importance in information-processing research have been measures such as the Continuous Performance Test (CPT) and the Partial Report Span of Apprehension (SPAN) that place high momentary loads on processing resources. The relationships between the two cognitive measures and between the two measures and clinical symptoms were examined in 50 patients with either DSM-III-R schizophrenia or schizoaffective disorder. The information-processing measures were modestly correlated with each other and with an estimate of verbal, but not nonverbal IQ. The SPAN was correlated with negative symptoms and the CPT with formal thought disorder. These results provide some evidence of convergent validity but also suggest that constructs other than high momentary processing load are implicated in their sensitivity to schizophrenia.

Adult↗
PubMed1990

Applications of voxel shifting in magnetic resonance imaging.

Due to the nature of three-dimensional Fourier transform (3-DFT) data acquisition in magnetic resonance imaging (MRI), the spatial relation between a resolved volume element (a voxel) and the object can be manipulated easily. Those manipulations have practical consequences in terms of registering slice positions with respect to features of interest in producing oblique reformatted images where volume resolution is preserved, and in generating reformatted images that project the viewing plane onto a surface through the object that has an arbitrary shape.

Fourier Analysis↗
PubMed1989

Induction of ovulation with subcutaneous pulsatile gonadotropin-releasing hormone: correlation with body weight and other parameters.

We treated 21 anovulatory infertile patients with subcutaneous pulsatile gonadotropin-releasing hormone (GnRH) administered via a syringe pump. Response to treatment was assessed by urinary estrogen excretion and ultrasound measurement of follicular growth. Ten patients ovulated and 8 subsequently conceived, for a total of 10 pregnancies. Human chorionic gonadotropin (hCG) was not administered routinely, but two patients required hCG to induce follicular rupture. The majority of the patients who conceived had a body mass index (BMI) of less than 21 and a luteinizing hormone (LH)/follicle-stimulating hormone ratio of less than 1. Conversely, those patients with either elevated BMI or LH or both generally failed to respond satisfactorily to this treatment. It is suggested that pulsatile GnRH is most likely to succeed in inducing ovulation if the BMI is less than 21 and the LH is normal, but is unlikely to be successful if there is both an elevated LH and a BMI of greater than 25. Between these two extremes, the response is variable and a therapeutic trial may be appropriate.

Anovulation↗
PubMed1989

Accessible magnetic resonance imaging.

The cost of magnetic resonance imaging (MRI) is driven by magnetic field strength. Misperceptions as to the impact of field strength on performance have led to systems that are more expensive than they need to be. Careful analysis of all the factors that affect diagnostic quality lead to the conclusion that field strength per se is not a strong determinant of system performance. Freed from the constraints imposed by high-field operation, it is possible to exploit a varied set of opportunities afforded by low-field operation. In addition to lower costs and easier siting, we can take advantage of shortened T1 times, higher contrast, reduced sensitivity to motion, and reduced radiofrequency power deposition. These conceptual advantages can be made to coalesce onto practical imaging systems. We describe a low-cost MRI system that utilizes a permanent magnet of open design. Careful optimization of receiving antennas and acquisition sequences permit performance levels consistent with those needed for an effective diagnostic unit. Ancillary advantages include easy access to the patient, reduced claustrophobia, quiet and comfortable operation, and absence of a missile effect. The system can be sited in 350 sq ft and consumes a modest amount of electricity. MRI equipment of this kind can widen the population base than can access this powerful and beneficial diagnostic modality.

Costs and Cost Analysis↗
PubMed1989

"Angiography" by magnetic resonance imaging: detailed vascular anatomy without ionizing radiation or contrast media.

Using software to transform magnetic resonance imaging (MRI) tomographic data into three-dimensional projections, we have produced "angiograms" of the abdominal aorta in 18 patients with occlusive (15) and aneurysmal (3) disease. This information may be displayed to demonstrate flow, cross-sectional diameter, or aortic surface anatomy. To test the accuracy of the MRI studies, we compared them at selected points with the transected aorta and with routine aortograms. Relative cross-sectional diameter estimated by MRI was within 15% of measured aortic diameter in 14 of the 18 vessels and enabled correct detection of thrombus in 16. We conclude that MRI may accurately image the diseased abdominal aortic wall. In addition, an angiographic display format may aid in the interpretation of these studies. Although MRI is not likely to replace aortography, it could be used adjunctively to define aortic wall thickness and the presence of thrombus.

Aged↗
PubMed1988

Diagnosis of trichomoniasis. Comparison of conventional wet-mount examination with cytologic studies, cultures, and monoclonal antibody staining of direct specimens.

The accuracy of (1) conventional wet-mount examination, (2) Papanicolaou-stained gynecologic smears, (3) a direct slide test using fluorescein-conjugated monoclonal antibodies against Trichomonas vaginalis, and (4) two different culture media for the diagnosis of trichomoniasis in a high-risk population of 600 women was compared. Use of Feinberg-Whittington or Diamond's culture medium resulted in a diagnosis of 82 and 78 cases, respectively, and the combination of two cultures identified 88 infected women. In comparison, wet-mount examination detected only 53 (60%) of the cases. Cytologic smears were interpreted as positive for T vaginalis in 49 (56%) of the 88 cases but also resulted in seven false-positive smears, and specimens from 18 women with negative cultures were interpreted as "suspicious" for trichomoniasis. Monoclonal antibody staining detected 76 (86%) of the 88 positive specimens, including 27 (77%) of the 35 cases missed by wet-mount examination. In summary, wet-mount and cytologic studies were insensitive, and cytology study was the least specific method for diagnosis of trichomoniasis. Direct immunofluorescence with monoclonal antibodies holds promise as a sensitive and specific alternative to cultures for rapid detection of T vaginalis in clinical specimens.

Animals↗
PubMed1986

Tetracycline resistance and tetM in pathogenic urogenital bacteria.

Clinical isolates of Gardnerella vaginalis, Streptococcus agalactiae, Bacteroides spp., and Mobiluncus spp. were screened for resistance to tetracycline and for the presence of the streptococcal tetM determinant. The S. agalactiae and G. vaginalis strains contained DNA sequences homologous to the tetM determinant, while strains of the other two genera did not.

Bacteria↗
PubMed1986

Two-dimensional thin-layer chromatography for the specific detection of hippurate hydrolysis by microorganisms.

Glycine, one of the end products of hippurate hydrolysis by microorganisms, was detected by a rapid, specific technique utilizing two-dimensional thin-layer chromatography. A loopful of growth of each organism from its suitable agar medium was washed, suspended, and incubated with 0.1% sodium hippurate for 30 min at 37 degrees C. The supernatant of the incubated suspension from each organism was then dansylated, and the dansyl derivatives were separated by two-dimensional thin-layer chromatography on polyamide sheets. Glycine, a product of hippurate hydrolysis, was detected under UV light. This technique does not require prolonged incubation and was found to be more specific and reliable than the standard ninhydrin reaction. In addition, it is inexpensive and can be easily conducted in a clinical microbiological reference laboratory. By this method, 100% (22/22) of Campylobacter jejuni and 0% (0/9) of Campylobacter coli reference strains were positive. In addition, 100% (13/13) of group B streptococci, 100% (24/24) of group D streptococci, and 90% (18/20) of Gardenerella vaginalis clinical isolates were positive for hippurate hydrolysis. This method is useful for the identification to the species level of Campylobacter organisms and the biotyping of Gardnerella organisms and for the detection of hippurate hydrolysis by unknown microorganisms.

Bacteria↗
PubMed1985

Radiation risks for patients having X rays.

In addition to radiation from naturally occurring radioactive materials and cosmic rays, individuals in developed countries receive radiation doses to bone marrow and gonads from the medical diagnostic use of X rays. A brief discussion of radiation epidemiology shows that deleterious effects are low even when doses are high. The concept of "acceptable risk" is introduced to help evaluate the small, but still existent, risks of radiation dose. Examples of bone marrow and gonadal doses for representative X-ray examinations are presented along with the current best estimates, per unit of X-ray dose, of the induction of leukemia or of genetic harm. The risk to the patient from an examination can then be compared with the normal risk of mortality from leukemia or of the occurrence of genetic defects. The risk increase is found to be very low. The risks to unborn children from radiographic examinations are also discussed. The benefit to the patient from information obtained from the examination must be balanced against the small risks.

Abnormalities, Radiation-Induced↗