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Biomedical subjects

K Murphy

Publications and source records attributed to K Murphy.

At least 217 records · Page 12Linked to original sources

A comparison between illumination and position pictorial depth cues.

It has long been established that pictorial depth is created by position and illumination cues, but the relative effectiveness of these cues is unknown. This study compared position cues in line illustrations to combined position and illumination cues in color illustrations for the amount and quality of depth depiction. Results show that including illumination cues in illustrations enhances the impression of space and that illustrations of shallow space are more affected than illustrations of deep space when illumination cues are deleted.

Depth Perception↗

Interferon therapy for condylomata acuminata.

Current therapy for condylomata acuminata (genital warts) is not consistently effective. Therefore, we conducted a randomized, double-blind trial to compare interferon alpha-2b with placebo in the treatment of this disorder. Our rationale was that interferon has both antiproliferative and antiviral properties. The placebo or interferon (1 X 10(6) IU) was injected directly into one to three warts three times weekly for three weeks. The injections were well tolerated by both groups of patients. The side effects of fever, chills, myalgia, headache, fatigue, and leukopenia occurred more commonly in the interferon group than in the placebo group, but such effects rarely disrupted daily routines. Only 13 of 296 patients (4 percent) discontinued therapy because of side effects (11 in the interferon group and 2 in the placebo group). Twenty-six other patients were excluded from analysis because of a loss to follow-up or other deviations from protocol, thus leaving 257 patients in the final evaluation. At one week after the completion of therapy, interferon had produced a large and significantly greater reduction in mean wart area (a 62.4 percent decrease), as compared with placebo (a 1.2 percent increase in mean area) (P less than 0.001). At the conclusion of the study (13 weeks after the completion of therapy), the mean wart area was still decreased 39.9 percent below the initial size in the interferon group, whereas it had increased by 46 percent over base-line measurements in the placebo group (P less than 0.001). At the same time, all treated warts had completely cleared in 36 percent of the interferon recipients and in 17 percent of the placebo recipients (P less than 0.001), whereas treated warts progressed in 13 percent of the interferon recipients and in 50 percent of the placebo recipients (P less than 0.001). We conclude that injection of interferon alpha-2b directly into genital warts appears to be an effective and fairly well-tolerated form of therapy.

Adolescent↗

Use of bretylium tosylate as prophylaxis and treatment in hypothermic ventricular fibrillation in the canine model.

We conducted a study to determine if bretylium tosylate (BT) is effective in the prophylaxis and treatment of hypothermic ventricular fibrillation (VF) in the setting of various maneuvers thought to induce this lethal arrhythmia. Twenty-two mongrel dogs were cooled to 24 C after being placed in a cold room. At 24 C, a double-blinded placebo or BT solution was infused. The dogs then were removed from the cold. They underwent the following sequential maneuvers: oral endotracheal extubation and intubation, central line and nasogastric tube placement, vigorous movement, and Swan-Ganz catheter insertion. If VF ensued, arterial blood gases were drawn, and BT was given only if refractory to countershock and epinephrine. Of the dogs that were given placebo, six of 11 (55%) fibrillated with manipulation, as compared with one of 11 (9%) dogs pretreated with BT (P = .067). Three of the 11 dogs that received BT fibrillated within minutes of its infusion. In the placebo dogs that fibrillated, four required BT and two defibrillated with countershock alone or with epinephrine prior to achieving stable rhythms.

Animals↗

Negative bone scans of joints after aspiration or arthrography: experimental studies.

It has long been suspected anecdotally that needle aspiration or contrast arthrogram before bone scan may cause a false-positive bone scan. This dictum often directs the sequence of events in the clinical workup of joint disease, yet data to support or refute this are lacking. This study was undertaken to generate such data. Fifty-six joints in mature dogs were examined, including hips, knees, elbows, and shoulders. The joints were examined in pairs; one joint was injected with Conray 60 for an arthrogram, and the contralateral joint was injected with an equal volume of normal saline to simulate a joint aspiration. Confirmation of needle placement and injection into the joints was made with fluoroscopic and digital subtraction imaging. Numbers of attempts required for aspiration and quantity of contrast material extravasated were noted for each joint. Baseline 99mTc-HDP or 99mTc-MDP bone scans were done before the experimental joint aspirations, with follow-up scans at 24 and 96 hr. The scans showed no significant change from baseline after either needle aspiration or arthrogram. When the diagnostic workup suggests the need for such a procedure, it should be performed. In contradiction to popular belief, joint aspiration and/or arthrogram did not affect a subsequent bone scan.

Animals↗

Alternating chemotherapy and thoracic radiotherapy with concurrent cisplatin-etoposide for limited-stage small-cell carcinoma of the lung.

Seventy patients with limited-stage small-cell lung cancer (SCLC) were given six courses of chemotherapy alternating two drug combinations: a combination of cyclophosphamide, doxorubicin (Adriamycin [Adria Laboratories, Columbus OH]) and vincristine (CAV) was alternated with cisplatin and etoposide at 3-week intervals. Thoracic radiotherapy was administered concurrently with the first cisplatin-etoposide chemotherapy. Prophylactic cranial irradiation (PCI) was administered after the completion of all chemotherapy. No maintenance treatment was used. Seventy-six percent of patients achieved a complete clinical response. The median survival was 78 weeks and the 2-year survival rate was 32% with an average follow-up of 3 1/2 years. Seventeen percent are currently alive and disease free. Cisplatin and etoposide can be administered concurrently with thoracic irradiation with acceptable toxicity. Our results justify further clinical research using alternating chemotherapy and concurrent thoracic irradiation and cisplatin-etoposide chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

Technetium-99m BIDA biliary scintigraphy in the evaluation of the jaundiced patient.

Biliary scintigraphy using 99mTc p-butyl acetanilidiminodiacetic acid (BIDA) was performed as part of the diagnostic evaluation on 96 patients with jaundice (serum bilirubin greater than 2 mg/dl) to assess its value in this group of patients. The results of scintigraphy revealed no obstruction to the flow of the scintigraphic agent into the duodenum in 54 patients, delayed appearance of the agent (normal upper limit 60 min) in the duodenum indicating partial obstruction in 22 patients, and complete obstruction of the duct demonstrated by absence of agent in the duodenum in 20 patients. The findings were correlated with the final diagnosis and the overall results show accuracy of 92.7%, sensitivity of 97.3%, and specificity of 89.8%. Biliary scintigraphy was thus found to be useful in differentiating nonobstructive, partially obstructive, and completely obstructive causes of jaundice.

Adolescent↗

Complete nucleotide sequences of three VH genes in Caiman, a phylogenetically ancient reptile: evolutionary diversification in coding segments and variation in the structure and organization of recombination elements.

Complete nucleotide sequences are described for three caiman (Caiman crocodylus crocodylus) immunoglobulin VH genes (C3, E1, and G4) that hybridize with a murine VH probe. The E1 and G4 genes are physically linked (intergenic distance, approximately equal to 6.5 kilobases) in the same transcriptional orientation but are not directly contiguous with the C3 gene. When the coding segments, including both framework and complementarity-determining regions, of these genes and the murine probe sequences are compared by metric analysis, it is apparent that the caiman genes are only slightly more related to each other than to the mammalian sequence, consistent with significant preservation of nucleotide sequence over an extended period of phylogenetic time. Based on the presence of transcriptionally critical 5' sequences and the absence of terminator codons, frameshift mutations, or other recognizable alterations, the genes do not appear to be pseudogenes. The E1 gene, however, is distinguished from other VH genes because (i) the spacer region within the 3' recombination signal sequence is 12 base pairs, typical of VK genes but not of VH genes, which possess 22- to 23-base-pair spacers and (ii) a near-perfect VH recombination signal sequence is present within the intervening sequence that splits the segment encoding the leader. These studies establish VH gene multiplicity in a species that arose prior to mammalian radiation and provide a description of differences in the configuration and location of recombination elements associated with an otherwise potentially functional gene.

Alligators and Crocodiles↗

Immunoglobulin VH gene structure and diversity in Heterodontus, a phylogenetically primitive shark.

A mouse VH probe has been used to identify and isolate VH homologs in a DNA library of Heterodontus francisci (horned shark). The complete nucleotide sequence of one VH gene, HXIA, has been determined and found to exhibit striking organizational homology and nucleotide identity with mammalian prototype VH genes. Metric analysis of the complete sequence is consistent with the early phylogenetic diversification of framework and complementarity-determining regions (CDR). Both the predicted amino acid sequence and the specific hybridization of the CDR2-specific, synthetic oligodeoxynucleotide probe in spleen mRNA suggest that HXIA is functionally expressed. A probe consisting of the entire coding region of this gene hybridizes with multiple components in Southern blot analysis of Heterodontus genomic DNA and together with the identification of additional unique VH+-lambda clones indicates that considerable complexity is associated with the germline VH gene family in a contemporary species that represents an early stage in the phylogenetic development of the vertebrates.

Amino Acid Sequence↗

Is the voluntary control of exercise in man necessary for the ventilatory response?

The ventilatory response to electrically induced exercise (EEL) was studied in eighteen normal subjects and compared with the response to performing the same exercise voluntarily (EV). EEL was produced by surface electrode stimulation of the quadriceps and hamstring muscles so as to cause a pushing movement at 1 HZ against a spring load; this produced no pain or discomfort. Matching of EV to EEL was achieved by subjects copying a tension signal recorded during EEL and displayed on a storage oscilloscope. There were no differences between the resting states measured before either form of exercise. The ventilatory response (change in ventilation as a ratio of the change in CO2 elimination) was similar in the two types of exercise. The increases in ventilation and CO2 elimination were greater with EEL. Small but significant increases in the gas exchange ratio and serum lactate were found for EEL but not for EV, suggesting an increase in anaerobic metabolism in EEL. End-tidal PCO2 showed little change in either form of exercise. In some runs end-tidal PCO2 rose, but insufficiently to account for the ventilatory response as judged by the response to inhaled CO2. In two subjects arterial blood samples showed small and inconsistent changes in both Pa,CO2 and PaO2 for EV and EEL. pH and base excess changes also were consistent with more anaerobiosis with EEL compared to EV. The first ten breaths of exercise were used to study the on transient. In EV, expiratory duration shortened and ventilation increased significantly on the first breath but CO2 elimination did not increase until the second breath; in EEL, these variables did not change significantly until the second breath. For the remainder of the on transient the pattern of the ventilatory response was similar for EV and EEL. By the end of the on transient both EV and EEL had reached approximately 80% of their final steady-state values. These results suggest that a normal ventilatory response can occur in the absence of a drive to exercise from the cortex.

Adult↗

The role of spinal cord transmission in the ventilatory response to exercise in man.

The ventilatory response to electrically induced exercise was studied in thirteen patients with traumatic spinal cord transection at or about the level of T6. The steady-state and on-transient responses to this exercise were compared with those obtained in eighteen normal subjects (Adams, Garlick, Guz, Murphy & Semple, 1984). Exercise was produced by surface electrode stimulation of the quadriceps and hamstring muscles so as to produce a pushing movement at 1 HZ against a spring load. At rest there was no significant difference between normals and patients, except that the patients had a lower CO2 elimination (VCO2) and end-tidal PCO2 (PET,CO2) and a higher heart rate. On exercise the mean rise in VCO2 for the patients was 172 ml min-1 (S.D. 72), and for the normals was 287 ml min-1 (S.D. 143). The corresponding mean changes in ventilation (VI) were 4.4 l min-1 (S.D. 2.2) and 7.6 l min-1 (S.D. 3.2). However, the ventilatory equivalent for CO2 (delta VI/delta VCO2) in the steady state was not significantly different between patients (26.0, S.D. 5.9) and normals (28.5, S.D. 7.4). In the steady state there was a mean rise in PET,CO2 of 0.9 mmHg (S.D. 1.4) in the normals, and 3.2 mmHg (S.D. 2.7) in the patients, but there was overlap between the two groups. In many experimental runs in both groups, PET,CO2 did not rise, and sometimes fell. Where PCO2 did rise, the ventilatory response to exercise could not be accounted for on the basis of the ventilatory sensitivity to CO2 inhalation. From arterial sampling in three of the patients it was found that when PET,CO2 rose, the corresponding change in Pa,CO2 was less. During the on transient, there was a significant rise in both VCO2 and VI by the second breath in both groups. At the end of the on transient the normal subjects had achieved 84% (S.D. 40) of the steady-state increase in VCO2 and 88% (S.D. 24) of the increase in VI. The corresponding values for the patients were 67% (S.D. 17) and 77% (S.D. 16) respectively; these differences between normals and patients are significant. The increase of VI during the on transient in the patients was achieved almost entirely by an increase in tidal volume whereas in normals, an increase in respiratory rate was a more important component. We conclude therefore that in man, spinal cord transection with a presumed loss of muscle afferents allows a ventilatory response to electrically induced exercise that cannot be explained by classical chemoreception.(ABSTRACT TRUNCATED AT 400 WORDS)

Carbon Dioxide↗

Amylase isoenzymes in the evaluation of trauma patients.

In traumatized patients, elevation of the levels of serum amylase is often noted and may lead to a diagnosis of pancreatitis or pancreatic injury. In the presence of multiple injuries, it is often difficult to evaluate clinically for pancreatitis or pancreatic injury. Since the serum amylase is derived from both the pancreatic and the salivary glands, it is useful to determine the origin of the elevated levels of serum amylase in these patients. A total of 31 patients including 21 trauma patients were studied, and the total serum amylase and also the pancreatic (P) and salivary (S) fractions were determined by isoelectric focusing. Compared with the normal control group, most trauma victims had elevated total amylase levels (normal, 30-128 U). In six patients with head and facial trauma, the P-fraction was 7.6 per cent, and the S-fraction was 92.4 per cent (normal, P 35-50%; S 50-65%), while in six patients with penetrating abdominal trauma, the P-fraction was 81 per cent, and the S-fraction was 19 per cent. These differences were statistically significant. The data demonstrate the value of measuring fractions of amylase in addition to total amylase levels. In patients with head and facial trauma alone, elevated levels of serum amylase are due to an increase in the salivary fraction. Elevation of total serum amylase in traumatized patients does not necessarily indicate pancreatic injury. Measurements of amylase fractions were thus useful in evaluation of trauma patients.

Amylases↗

Complete nucleotide sequence of an immunoglobulin VH gene homologue from Caiman, a phylogenetically ancient reptile.

Immunoglobulin variable (V) gene regions typify extensive multigenic families in terms of overall size, chromosomal arrangement and presence of large numbers of apparent pseudogenes. A unique mechanism of somatic reorganization involving recombination of VH, D and JH or VL and JL segments accompanies the differentiation of lymphoid cells and together with somatic mutation and other types of recombination accounts for V-region diversity. Although these processes have been well characterized in higher mammals, little is known concerning their origin and diversification during phylogenetic time. Previously, we described the blot-hybridization characteristics of murine VHIII probes with restriction enzyme-digested genomic DNA isolated from several phylogenetically critical species, including Caiman crocodylus, a modern representative of an ancient reptilian subclass. Here we have used a murine probe, S107V, to select homologous clones from a library of Caiman genomic DNA constructed in a lambda bacteriophage. The complete nucleotide sequence of a Caiman gene homologous to the murine VH gene and its adjacent 5' and 3' region is described. Comparison of the sequence with mammalian prototypes shows evidence of considerable organizational and structural homology extending outside the presumed VH-coding region and including elements believed to be involved in somatic recombination. Inferences about the evolution of this multigenic family can now be extended to the level of phylogenetic class.

Alligators and Crocodiles↗