Biomedical subjects

K Campbell

Publications and source records attributed to K Campbell.

At least 145 records · Page 8Linked to original sources

PubMed1991

The mouse IgH 3'-enhancer.

A lymphoid-specific transcription enhancer element has recently been identified at the far 3' end of the rat immunoglobulin heavy chain (IgH) locus. Sequence analysis presented here reveals that this enhancer is flanked by a 350-bp invert repeat, giving a structure reminiscent of a transposable element. We therefore screened for the equivalent enhancer in the mouse to determine whether its presence was conserved during evolution. A mouse homologue was indeed identified and is located 16 kb downstream of the C alpha 1 exon. It is also flanked by invert repeats and these are not repeated throughout the genome. The mouse and rat enhancers retain high sequence homology. As regard activity, the IgH 3'-enhancer is lymphoid specific. However, this activity was detected in two plasmacytoma lines tested but not in two B cell lymphomas nor in HeLa cells suggesting that the enhancer may only play a stage-specific role during lymphocyte differentiation. As regards function within the IgH locus, we found that inclusion of the mouse IgH 3'-enhancer (in addition to the intron-enhancer) on mu gene expression plasmids effected a small increase in mu mRNA levels in stable plasmacytoma transfectants.

Animals↗

PubMed1991

Ovarian neoplasms and the risk of adnexal torsion.

Previous reports examining adnexal torsion suggested that benign ovarian neoplasms are more likely to undergo torsion than malignant ovarian neoplasms. To our knowledge, this clinical observation has not been quantified. To examine this hypothesis, we reviewed our experience with ovarian neoplasms found at the time of surgery over a 10-year period. Benign ovarian neoplasms had a 12.9-fold increased risk of undergoing adnexal torsion when compared with malignant ovarian neoplasms (95% confidence interval, 10.2 to 15.9). The histologic type of ovarian neoplasm does not appear to affect the rate of adnexal torsion. Adnexal torsion rarely involves cancer.

Adnexal Diseases↗

PubMed1991

Congenital heart disease, parental stress, and infant-mother relationships.

The effect of congenital heart disease on early social relationships was assessed by observing 42 infants with the disease and 46 healthy infants in a standardized laboratory setting with their mothers. Significantly fewer infants with congenital heart disease, in comparison with healthy peers, were considered to have secure relationships with their mothers. The quality of the infant-mother relationship in the group with congenital heart disease was not related to parents' reports of their own stress or psychologic well-being. Severity of illness did not have a direct effect on the quality of the infant-mother relationship, but securely attached infants showed more subsequent improvement in health than insecurely attached peers showed. Attention to the infant-mother relationship in clinical care may improve the social development of babies with congenital heart disease and may have positive effects on physical health as well.

Adult↗

PubMed1991

Long-term smoking intervention at the worksite: effects of quit-smoking groups and an "enriched milieu" on smoking cessation in adult white-collar employees.

Maximizing the potential of worksites for smoking intervention remains elusive. We hypothesized that long-term effectiveness of group intervention would be enhanced when offered within an "enriched milieu" (full program) compared with relative isolation (group only). The data failed to support the hypothesis. Although sustained abstinence rates were higher at full-program sites (50%) than at group-only sites (44%), the difference did not achieve statistical significance. Initial (35% vs. 47%) and 12-month (18% vs. 22%) quit rates at full-program and group-only sites also failed to demonstrate the "benefit" of the "enriched milieu."

Adult↗

PubMed1991

A study of chromosome 11p13 translocations involving TCR beta and TCR delta in human T cell leukaemia.

A frequent site of translocation damage in human T-ALL has been localized to a specific region of chromosome band 11p13. Five new T-ALL cases are described which break in the major T-ALLbcr region of 11p13, two involving a novel translocation t(7;11)(q35;p13), with breakage at the T cell receptor (TCR) beta gene from 7q35, and three involving TCR delta from 14q11 in the more common t(11;14)(p13;q11). Analysis of the mechanism of one T-ALLbcr/TCR beta translocation and a previously described t(11;14)(p13;q11) was conducted by genomic cloning of translocation breakpoints, using the polymerase chain reaction (PCR). Both seem to have occurred by recombinase error, but only the t(7;11) showed sequence-specific joining. Nonetheless recombinase mediation of the t(11;14) is implied by the presence of N-region addition (a hallmark of recombinase joins) on both derivative chromosomes. These observations reinforce the view that translocations in the T-ALLbcr region of chromosome 11p13 are a major lesion in human T-ALL. In addition, these can occur by mimicry of VDJ joining, but sequence specificity is not obligatory.

Base Sequence↗

PubMed1990

Ca-ATPase isozyme expression in sarcoplasmic reticulum is altered by chronic stimulation of skeletal muscle.

Chronic stimulation of a predominantly fast skeletal muscle enhanced the expression of type I (slow muscle) Ca-ATPase and suppressed the expression of the type II (fast muscle) Ca-ATPase. Monoclonal antibodies IID8 and IIH11 against type I (slow) and type II (fast) isozymes respectively, were used to type the Ca-ATPases of the isolated SR (sarcoplasmic reticulum) by Western blots, and the Ca-ATPases of the muscle fibers by immunohistochemistry. Of the fibers from control muscles 80% stained for the type II isozyme and 20% for the type I isozyme. Following chronic stimulation all fibers stained for type I isozyme and none stained for type II isozyme. Ca-ATPase isozyme distribution in isolated SR confirmed this effect of chronic stimulation. The calcium uptake activities of homogenates of stimulated muscles were 22% of the control muscles. The Ca-ATPase and calcium-uptake activities of the isolated SR from stimulated muscles were, respectively, 32 and 45% of the control muscles.

Animals↗

PubMed1990

Bilateral ovarian neoplasms and the risk of malignancy.

Bilateral ovarian neoplasms are believed more likely to be malignant than are unilateral neoplasms. To our knowledge, this clinical tenet has not been evaluated or quantified. To test this hypothesis, we conducted a 10-year review of ovarian neoplasms found at the time of celiotomy at the Women's Hospital, Los Angeles County-University of Southern California Medical Center. Overall, women with bilateral neoplasms had a 2.6-fold increased risk of malignancy when compared with women who had unilateral neoplasms (95% confidence interval, 2.0 to 3.4; p less than 0.001). The age-standardized relative risk was 1.8 (95% confidence interval 1.4 to 2.3). When standardized for the effect of menopausal status, the relative risk was 2.0 (95% confidence interval, 1.6 to 2.5). Bilaterality is associated with a doubling in the risk of cancer, a highly significant difference.

Age Factors↗

PubMed1990

Maternal sensitivity and the security of infant-mother attachment: a Q-sort study.

40 mothers and their 12-month-old infants were observed twice at home by 2 observers for 2 hours. After the second visit, the observers described the infant using the Waters Attachment Behavior Q-sort and the mother's interactive behavior with the Maternal Behavior Q-sort developed by the present authors and Ainsworth's rating scales. Maternal sensitivity was unrelated to maternal age, income, or SES, but correlated positively with maternal education. Mothers of more difficult children were less sensitive. A strong relation was found between infant attachment and maternal sensitivity as measured by the Maternal Behavior Q-sort and by the Ainsworth scales. Using the Q-sort procedure, mothers of more secure infants were more frequently characterized as noticing their babies' signals and using these signals to guide their behavior; they also were more knowledgeable about their infant and appeared to enjoy them more than mothers of less secure infants.

Adult↗

PubMed1990

Immitance audiometry.

Immitance audiometry is a safe, simple, reliable, and relatively objective method of determining middle-ear function that provides advantages for examining the difficult patient because minimal cooperation is needed. Acoustic-immitance measurements obtain sophisticated data that give us valuable information about the middle ear mechanism as a whole. It can be used in a quiet office environment. Immitance audiometry can confirm a doubtful otoscopic diagnosis and screen for ear disease. There are limitations to observer reliability with otoscopy, which has good sensitivity but poor specificity, in contrast to immitance audiometry. The tympanogram can be classified into four different patterns on the basis of its characteristics. These patterns are diagnostic, distinguishing normal function from various types of middle ear pathology. Immitance audiometry has very high sensitivity and specificity. The acoustic reflex, a contraction of the stapedius muscle following an intense auditory stimulus, can be valuable in determining a conductive hearing loss and many other otologic diagnoses. As a screening tool, immitance audiometry is most valuable in populations at risk for middle ear effusion, primarily those aged 7 months to 5 years. Significant improvements in measurements of ear function also allow us to be more precise in the diagnoses of otosclerosis, perforation of the tympanic membrane, ossicular discontinuity, facial nerve dysfunction, and brain stem disorders.

Acoustic Impedance Tests↗

PubMed1990

Asymmetrical auditory probe evoked potentials during REM and NREM sleep.

Two experiments were conducted to evaluate interhemispheric differences in late auditory evoked potentials (AEPs) during rapid-eye-movement (REM), Stage 2, and Stage 4 sleep. In the first study, 1,000-Hz stimuli [80 db (SPL)] were presented binaurally at a rate of 1/1.1 s. Analyses of variance were computed on the absolute difference in the amplitude of right and left evoked responses. N1 AEPs were significantly more asymmetrical in Stage 4 sleep compared to either REM or Stage 2 sleep. A second study was conducted with a wider topographical electrode distribution. This study used both a long and a short interstimulus interval with 500-Hz 80-db SPL tone pips. The absolute difference in the amplitude of right and left AEPs was compared across sleep stage. Asymmetries were larger in Stage 4 sleep than in either REM or Stage 2. Examination of these data indicated relative hemispheric balance in REM and Stage 2 sleep with largest asymmetries in Stage 4. The results do not support the view that REM and non-REM sleep stages are associated with differential activation of the two cerebral hemispheres. Rather, they suggest that the sleep cycle is characterized by variations in the degree of asymmetry. Asymmetries in Stage 4 sleep were not consistently in favor of the left hemisphere.

Adolescent↗

PubMed1990

Umbilical cord prolapse. A contemporary look.

The true impact of medical intervention for umbilical cord prolapse is unknown. We reviewed all cases of the condition over a nine-year period at Women's Hospital, Los Angeles County-University of Southern California Medical Center, in an attempt to answer this question. The perinatal mortality rate associated with umbilical cord prolapse increased significantly with decreasing levels of medical intervention. No fetal deaths occurred in the hospital.

Adolescent↗

PubMed1989

Role of prostacyclin in the splanchnic hyperemia contributing to portal hypertension.

To determine the possible role of prostacyclin (PGI2) as a mediator of the splanchnic hyperemia seen with portal hypertension, the portal and mesenteric hemodynamics in normal and portal hypertensive rabbits were studied before and after cyclo-oxygenase blockade. Three weeks after partial portal vein ligation, splenic pulp pressure was elevated from 4.3 +/- 0.9 to 9.8 +/- 0.8 mmHg (p less than 0.01). Mesenteric blood flow increased from 77.0 +/- 4.7 ml.min-1.100 g-1 to 99.1 +/- 5.19 ml/min-1/100 g-1. Mesenteric vascular resistance fell from 0.82 +/- 0.6 mmHg/ml-1/min-1 to 0.49 +/- 0.07 mmHg/ml-1/min-1 (p less than 0.01). These hemodynamic changes were associated with a 27.3 +/- 0.2% rise in systemic arterial levels of PGI2 (p less than 0.01) and were substantially ameliorated by cyclo-oxygenase blockade with indomethacin. The effects of indomethacin blockade were reversed by exogenous PGI2. Moreover, in normotensive rabbits, infusion of PGI2 reproduced the splanchnic hyperemia and caused a very small but significant increase in portosystemic shunting. These findings support the previously proposed concept that splanchnic hyperemia may contribute to the maintenance of chronic portal hypertension. Furthermore, they suggest that this effect may be partially mediated by splanchnic PGI2 production.

Animals↗

PubMed1989

Effects of hyperventilation, hypothermia, and altered blood viscosity on cerebral blood flow, cross-brain oxygen extraction, and cerebral metabolic rate for oxygen in cats.

Therapies including hyperventilation (HV) and hypothermia (HT) are currently simultaneously used in brain-injured children at risk for cerebral swelling to reduce cerebral blood flow (CBF) and alter cerebral metabolic rate for oxygen (CMRO2). Since HV and HT may contribute to significant patient morbidity, we evaluated the effects of these treatments in combination on CBF, CMRO2, and cross-brain oxygen extraction (CBO2) using the Kety-Schmidt technique before controlled bleeding to alter blood viscosity in 20 lightly anesthetized, paralyzed cats, and after bleeding in another 17 cats. The degree of HV (PaCO2 24 to 26 torr) and HT (32 degrees and 30 degrees C) used were representative of that employed in pediatric neurointensive care. HV at normothermia resulted in a significant decline in CBF (P less than .05) and an unchanged CMRO2. HV and HT together to 32 degrees C resulted in a further significant fall in CBF and CMRO2 (p less than .05), but an unchanged CBO2. Further cooling of the animal to 30 degrees C during HV, both before and after controlled bleeding, resulted in no further significant fall in CBF, CBO2, or CMRO2. This relationship was found despite a significant fall in Hgb (p less than .001), suggesting that blood viscosity did not significantly influence CBF at this temperature. Our data suggest that HT to 32 degrees C during HV may have therapeutic benefit by decreasing CBF and CMRO2, but further cooling to 30 degrees C may not result in further cerebral protective effects.

Animals↗

PubMed1989

Distribution and metabolism of 1,2,4-trimethylbenzene (pseudocumene) in the rat.

1. Single doses of 1,2,4-trimethylbenzene (124TMB) or 14C-124TMB were administered orally to rats for metabolism and distribution studies. 2. 14C-124TMB was rapidly and widely distributed throughout the body with the highest levels in adipose tissue. No other preferential uptake of 14C-124TMB by any of the organs or tissues examined was evident. 3. Tissue levels declined rapidly within 24 h after dosage, with more than 99% of the administered radioactivity recovered in the urine during this period. 4. A complex mixture of isomeric trimethylphenols, dimethylbenzyl alcohols, dimethylbenzoic acids and dimethylhippuric acids excreted in the urine accounted for more than 81% of the administered dose. The major metabolites were 3,4-dimethylhippuric acid (30.2% dose), 2,4-dimethylbenzyl alcohol (12.7% dose, primarily as sulphate and glucuronide conjugates) and 2,5-dimethylbenzyl alcohol (11.7% dose, primarily as sulphate and glucuronide conjugates).

Administration, Oral↗

PubMed1989

Relative frequency of primary ovarian neoplasms: a 10-year review.

The relative frequency of ovarian neoplasms varies according to information in different texts. In an attempt to clarify the distribution of primary ovarian neoplasms by decades of life, a 10-year retrospective review of 861 women with a postoperative diagnosis of an ovarian neoplasm was undertaken. Benign cystic teratoma was the single most common ovarian neoplasm, accounting for 44% of all neoplasms, and was 57% more frequent than benign serous tumors. Germ cell neoplasms were the most common group of benign ovarian neoplasms; epithelial neoplasms were the most common malignant neoplasm. Stromal neoplasms and neoplasms of low malignant potential were uncommon at all ages. The risk that an ovarian neoplasm was malignant increased 12-fold from ages 20-29 to 60-69. The overall risk that an ovarian neoplasm was malignant was 13% in premenopausal women and 45% in postmenopausal women.

Adult↗

PubMed1988

Generalized demodicosis in a cat responsive to amitraz.

Generalized demodicosis was diagnosed in a 14-year-old castrated male domestic short-hair cat. No underlying disease was detected. The cat responded incompletely or poorly to commonly recommended treatment, but responded well to total body dipping with 0.0125% amitraz at weekly intervals.

Administration, Topical↗

PubMed1988

Effects of a faculty prepaid group practice in a pediatric primary care clinic.

Medical student and resident education at a hospital-operated pediatric primary care clinic (PPCC) was threatened by chronic financial deficits and by a state mandate that all patients receiving medical care through the state Aid to Families with Dependent Children program be enrolled in a health maintenance organization (HMO). To comply with the mandate, the PPCC was reorganized in 1984 as a faculty-operated prepaid group practice independent of the hospital. The new PPCC contracted with an HMO to provide care, with reimbursement based on capitation. The PPCC continues to serve the same patient population as before the reorganization, continues its teaching activities, and no longer has financial deficits. The experience at this clinic shows that converting to a faculty prepaid group practice can be cost-effective, promote efficiency, and improve faculty-hospital relations. Such a group practice is an appropriate organization for maintaining medical education programs while providing care in a capitation payment system.

Aid to Families with Dependent Children↗

PubMed1988

Subcellular localization of the human immunodeficiency virus trans-acting art gene product.

The genome of the human immunodeficiency virus is distinguished from other animal retroviruses by the presence of several additional open reading frames. The protein product of one of these novel genes, which has been termed art or trs, is required for the expression of the virus structural genes but not for the expression of virus encoded regulatory proteins. Immunocytochemistry and subcellular fractionation demonstrate that the art protein is located predominantly in the nucleus. Therefore, any proposed mechanism for the function of art is likely to involve nuclear events.

Animals↗