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K Sorensen

Publications and source records attributed to K Sorensen.

At least 37 records · Page 2Linked to original sources
PubMed1994

Peroxide accumulation in detergents.

It is known that polyether detergents have a propensity for peroxide accumulation but the rate of this accumulation and the conditions under which it occurs are not well-appreciated. We here describe the use of the FOX (ferrous oxidation in Xylenol orange) assay as a screen for detergent peroxide accumulation. We also show that a chain-breaking antioxidant, but not a metal-chelating agent block peroxide accumulation in detergent stored in the light at room temperature.

Butylated Hydroxytoluene↗
PubMed1994

Surgical treatment of aortic coarctation in infants younger than three months: 1985 to 1990. Success of extended end-to-end arch aortoplasty.

There remains controversy regarding the appropriate surgical treatment of coarctation of the aorta in infants. In 1985 we introduced the extended end-to-end repair into our practice and now wish to present a review of our recent experience. One hundred fifty-one infants younger than 3 months of age underwent repair of coarctation between 1985 and 1990. In 25% and 33% of the patients, there was hypoplasia of the isthmus and of the transverse arch, respectively. Surgical procedures were as follows: subclavian flap angioplasty in 15 patients, resection with a traditional end-to-end anastomosis in 43, and resection with an extended end-to-end anastomosis into the arch in 77. In 30 patients, the extension was proximal to the origin of the left carotid artery (radically extended end-to-end anastomosis). Other procedures were used in 16 patients. Mortality (13 early and 12 late deaths) was related on multivariate analysis to the presence of an associated major heart defect, preoperative resuscitation, and direct postoperative gradient over the arch. This immediate postoperative gradient was significantly lower after both extended and radically extended end-to-end anastomosis if there was a hypoplastic isthmus, and after radically extended end-to-end anastomosis if the transverse arch was hypoplastic. Actuarial freedom from recoarctation at 4 years was 57% (confidence limits 28% to 78%) after subclavian flap angioplasty, 77% (confidence limits 60% to 87%) after end-to-end anastomosis, 83% (confidence limits 66% to 92%) after extended end-to-end anastomosis and 96% (confidence limits 77% to 100%) after radically extended end-to-end anastomosis. We conclude that the extended end-to-end anastomosis and radical end-to-end anastomosis appear to offer the best prognosis for all infants with coarctation. The technique can be applied successfully to almost all types of arch anomalies.

Age Factors↗
PubMed1994

Outcome measures for the neonatal management of pulmonary atresia with intact ventricular septum.

The outcome in 135 patients with pulmonary atresia with intact ventricular septum was reviewed in terms of actuarial survival and "suitability" for eventual definitive repair (defined as having a tricuspid valve diameter larger than 2.4 standard deviations below the mean normal beyond the neonatal period). Of patients who underwent an initial closed valvotomy, 50% were dead, 22% were alive and suitable, and the remaining 28% were alive but unsuitable for definitive repair at 5 years. None of 66 patients who underwent primary shunt alone achieved suitability and 52% were dead at 5 years. No mode of neonatal closed valvotomy was consistently satisfactory: in only 10 of 26 survivors with serial measurements did the neonatal valvotomy alone achieve decompression to subsystemic pressures. Only half of the decompressed ventricles achieved growth of the tricuspid valve disproportionate to somatic growth as a result of the neonatal procedure. Strategies for the neonatal treatment of pulmonary atresia with intact ventricular septum should not rely on closed operations on the pulmonary valve to optimized right ventricular growth.

Actuarial Analysis↗
PubMed1993

Use of seronegative samples for the calibration and reporting of serological enzyme immunoassay results.

For evaluation of serological assays, a seropositive reference sample is often arbitrarily assigned a value (EIU) against which test samples are compared. An alternate method, in which seronegative samples are identified by iteration and in turn used to established mean and standard deviation for the quantification (in units of Standard Deviation Ratio (SDR)) of each tested sample, was investigated on 1100 serum samples routinely tested for IgG against Borrelia burgdorferi. Of the 76 specimens that were positive in the EIU system, our computerized SDR method classified 9 as borderline and 67 as positive, none as negative. Of the 917 EIU-negative specimens, the SDR method classified 4 as borderline and 913 as negative, none were SDR positive. We conclude that the SDR has numerous advantages: lower number of borderline specimens found, its computer automation and its more stable results. The method is only suited for larger assays.

Antigens, Bacterial↗
PubMed1993

Impaired endothelial function occurs in the systemic arteries of children with homozygous homocystinuria but not in their heterozygous parents.

OBJECTIVES: Because endothelial dysfunction is an early event in atherogenesis, we aimed to determine whether endothelial function is normal or impaired in the systemic arteries of children with homozygous homocystinuria or in those of heterozygous adults, or both. BACKGROUND: Homocystinuria is strongly associated with premature vascular disease in homozygotes, and even heterozygotes have been shown to be at increased risk from early atherosclerosis associated with hyperhomocystinemia. METHODS: We conducted noninvasive studies on the superficial femoral or brachial arteries of 9 children aged 4 to 17 years (mean 11) with homozygous homocystinuria and on the brachial arteries of 14 obligate heterozygous parents age 33 to 49 years (mean 41). Each subject was matched with two control subjects. Using high resolution ultrasound, we measured vessel diameter at rest, during reactive hyperemia (with flow increase causing endothelium-dependent dilation) and after sublingual administration of nitroglycerin (an endothelium-independent vasodilator). RESULTS: Flow-mediated dilation was observed in the control children (9 +/- 0.6%, range 6% to 14%) but was impaired in the children with homocystinuria (2.8 +/- 0.7%, range 0% to 7%, p < 0.0001). In contrast, nitroglycerin-mediated dilation was similar in both groups (15.7 +/- 1.6% vs. 13.1 +/- 1.2%, p = 0.27), indicating that the impaired flow-mediated dilation is secondary to endothelial dysfunction. In the heterozygous parents, both flow-mediated dilation and nitroglycerin responses (6.3 +/- 0.9%, 17 +/- 1.4%, respectively) were similar to control values (6.8 +/- 0.7%, 20.7 +/- 1.7%, p > 0.10). CONCLUSIONS: Children with homozygous homocystinuria had impaired endothelial function in the systemic arteries as early as 4 years of age, representing an early event in their premature vascular disease. However, endothelial function was preserved in the heterozygous adults.

Adolescent↗
PubMed1993

Ventricular expression and circulating levels of immunoreactive dynorphin in heart transplant recipients.

1. Dynorphin, an endogenous opioid peptide, acts on specific kappa-opioid receptors in the rat heart for the local regulation of atrial natriuretic peptide release. No known study has examined the expression of dynorphin in the human heart. 2. In the present study a specific radioimmunoassay technique was used to determine ventricular expression of dynorphin at the peptide level in endomyocardial biopsy specimens and in plasma obtained from 13 heart transplant recipients. Ventricular biopsy specimens collected from 10 patients without cardiac complications during necropsy (less than 24 h from time of death) and plasma samples from 10 normal healthy subjects were used as controls. 3. The immunoreactive level of ventricular dynorphin was higher in heart transplant recipients (mean +/- SEM 141 +/- 32 pg/mg of soluble protein, range 7-573 pg/mg of soluble protein, P < 0.001) than in control subjects (16 +/- 3 pg/mg of soluble protein, 2-34 pg/mg of soluble protein). The plasma concentration of immunoreactive dynorphin was also higher (P < 0.001) in heart transplant recipients (mean +/- SEM 14 +/- 1 pg/ml, range 5-39 pg/ml) than in normal healthy subjects (7 +/- 0.4 pg/ml, 5-10 pg/ml). No relationship was observed between ventricular and plasma levels of dynorphin. 4. These results show that immunoreactive levels of dynorphin in plasma and ventricle are increased after heart transplantation, suggesting a possible pathophysiological role for dynorphin in the heart.

Adolescent↗
PubMed1993

Ventricular expression of brain natriuretic peptide gene following orthotopic cardiac transplantation in children--a three year follow up.

OBJECTIVE: The aim was to examine ventricular brain natriuretic peptide (B-type natriuretic peptide, BNP) gene expression and to determine its relationship with ventricular BNP and circulating BNP levels in paediatric cardiac transplant recipients, over a three year period after transplantation. METHODS: Total RNA extracted from endomyocardial right ventricular biopsy tissues (n = 26) of 13 cardiac transplant recipients (age range 5-17 years) and 10 normal hearts obtained at necropsy (age range 19-76 years) as controls was analysed by northern and slot blot hybridisations. Specific radioimmunoassay techniques were used to determine levels of BNP and atrial natriuretic peptide (A-type natriuretic peptide, ANP) in plasma (n = 26) and ventricular biopsy (n = 26) samples. RESULTS: Ventricular BNP messenger ribonucleic acid (mRNA) levels from slot blot hybridisations in the transplanted heart [122(3) arbitrary units, range 97-143] were significantly higher (p < 0.01) than in the normal heart [63(5) arbitrary units, range 37-98]. Northern blot hybridisations confirmed this result and gave a major BNP mRNA transcript of approximately 900 nucleotides. There was no significant relationship between ventricular BNP mRNA levels and ventricular BNP (r = 0.15, p = 0.5, n = 26) or plasma BNP levels (r = 0.16, p = 0.4, n = 26). There was also no significant relationship between ventricular BNP mRNA levels and any of the haemodynamic variables, or immunosuppressive drugs. A ventricular ANP RNA transcript of approximately 900 nucleotides was detected in the transplanted heart but was below the limit of detection in the normal heart. For the long term study, increased levels of BNP and ANP in both plasma and ventricular samples were observed in the first year after transplantation, with a significant reduction (p < 0.01) in levels three years later. CONCLUSIONS: Ventricular BNP gene expression is increased at the mRNA level after heart transplantation in children. Expression of both ventricular BNP mRNA and ANP mRNA in the transplanted heart may be an important response in the modulation of cardiac function after transplantation.

Adolescent↗
PubMed1990

Bone metastasis from gynecologic carcinomas: a clinicopathologic study.

Between 1948 and 1984, autopsies were performed on 305 patients with primary carcinomas of the cervix, endometrium, ovaries, fallopian tubes, vulva, and vagina. Skeletal metastases were detected premortem and at autopsy in 49 cases (16.1%): cervix, 20 (40.8%); endometrium, 17 (34.7%); ovary, 7 (14.3%); vulva, 4 (8.2%); fallopian tube, 1 (2%). There were no cases of osseous metastasis from vaginal carcinoma. The incidence and sites of metastasis from these gynecologic carcinomas were correlated with their clinical and histopathologic classifications. This clinicopathologic study, based on autopsy data, demonstrates that osseous metastases are not uncommon, are significantly greater than clinically appreciated, and correlate with advanced anatomic stage and histopathologic type and grade.

Autopsy↗
PubMed1990

Induction of cervical neoplasia in the mouse by an extract of cells infected by varicella-zoster virus.

Since several human herpesviruses, including varicella-zoster virus (VZV), have been demonstrated to transform mammalian cells in vitro, VZV was tested in a mouse model of virus-induced cervical neoplasia to determine whether it is oncogenic in vivo. Herpes simplex viruses types 1 and 2 and cytomegalovirus have been previously shown to induce cervical neoplasia in this mouse model. VZV was propagated in WI-38 cell cultures and inactivated by ultraviolet irradiation. Control material was prepared in an identical manner from uninfected cell cultures. Cotton tampons, saturated with inactivated virus or control material, were inserted into the vaginas of C57BL mice three times a week for 60 weeks. Cervical dysplasia was detected in 40% and invasive carcinoma in 34% of virus-exposed mice by histological examination. No lesions were detected in control animals. These observations indicate that VZV, or some product of virus-infected cells, is oncogenic in vivo for the mouse cervix.

Animals↗
PubMed1990

Outcome in mild and moderate cervical dysplasias related to the presence of specific human papillomavirus types.

In situ hybridization with biotinylated DNA viral probes (ISH-B) for human papillomavirus (HPV) types 6/11, 16, 18, 31, and 33 was used to study the outcome in 32 cases of mild and 21 cases of moderate cervical dysplasia with koilocytotic change that were followed for an average of 27 mo. The rates of regression, persistence, and progression for cervical intraepithelial neoplasia (CIN) I and CIN II were 50%, 41%, and 9%, and 43%, 48%, and 9%, respectively. While progression of HPV 16 CIN I and II lesions was observed, regression occurred in 80% (four of five) and 43% (three of seven) of CIN I and II HPV 16-positive lesions, respectively. Regression was also seen in lesions that contained HPV 31 or HPV 33. All of the HPV 18 lesions persisted. The findings are compared with those of previous studies. Since some of the assumed more aggressive viral types can regress when followed by cytologic and biopsy examinations, caution must be exercised when attempting to predict the clinical outcome based solely on the specific viral type present in a given CIN lesion.

Adolescent↗
PubMed1989

Transthoracic needle aspiration biopsy in inflammatory pseudotumors of the lung.

The cytologic findings on transthoracic needle aspiration biopsy in four patients with pulmonary inflammatory pseudotumor are described. These findings have not been previously illustrated in the literature. The main cytologic components of this lesion are histiocytes, lymphocytes, fibroblasts, pneumocytes, and plasma cells. Familiarity with these features is essential to avoid misdiagnosis and possible overtreatment.

Adenocarcinoma↗
PubMed1989

Newer techniques of laryngeal reinnervation.

We relate the experience obtained in the use of the right superior laryngeal nerve (motor branch)--cricothyroid muscle pedicle flap in dogs in an attempt to reinnervate the right posterior cricoarytenoid muscle (PCA). The right vocal cord was paralyzed by severance and removal of 2.5 cm of the right recurrent laryngeal nerve. Evaluation 6 months postoperatively revealed the vocal fold remobilization on the right side to have an average of about one half the mobility of the left, normal side. After the recurrent laryngeal and superior laryngeal nerves on the left were severed, the vocal cord mobility dropped to only about one fourth. This suggests that the dogs had contralateral reinnervation. Nevertheless, the right vocal cord mobility, driven only by the right superior laryngeal nerve, was enough to secure an adequate airway without the need for a tracheotomy. This experiment was statistically significant on comparison with a control group. Electromyographic studies as well as PCA histochemistry were performed.

Animals↗
PubMed1989

Newer technique of laryngeal reinnervation: superior laryngeal nerve (motor branch) as a driver of the posterior cricoarytenoid muscle.

This report analyzes the experience gained using two different techniques to reinnervate the paralyzed vocal cord. In the neurotization group, the superior laryngeal nerve (SLN) motor branch-cricothyroid muscle pedicle was used to reinnervate the posterior cricoarytenoid muscle. In the direct nerve anastomosis group, the SLN was anastomosed to the abductor branch of the recurrent laryngeal nerve (RLN), and the ansa hypoglossi (AH) to the adductor branch of the RLN. A third group of animals (control) had the right RLN sectioned without any anastomosis. About 5 to 6 months postoperatively the animals were killed painlessly and evaluated. The neurotization group revealed vocal fold mobilization on the right side to have an average of about half of the mobility of the left, normal side. After the RLN and SLN on the left were severed as well as the AH bilaterally, the vocal cord mobility was reduced to about one fourth. The direct nerve anastomosis group showed about fourfold less vocal cord mobility than the neurotization group. After the SLN, RLN, and AH were severed bilaterally, the control group showed no vocal cord mobility. The neurotization technique has been selected for further experimentation in human adults.

Anastomosis, Surgical↗
PubMed1989

Direct nerve implantation vs. nerve-muscle pedicle: a comparative study of reinnervation in the rabbit.

To determine the optimal method for reinnervation of the paralyzed head and neck musculature, we compared direct muscular nerve implants (DNI) with nerve-muscle pedicles (NMP) in rabbits. In 25 anesthetized animals, one ansa hypoglossi nerve was cut. Five animals served as controls and two groups of 10 each received cross-over DNIs or NMP from one sternothyroid to the contralateral sternohyoid muscle. The transplanted nerves of animals that survived long enough for neurotization to occur (8 DNIs, 5 NMPs) were stimulated with 3 to 10 mA. 0.05 msec pulse trains to obtain force curves from corresponding straps. Fiber diameters and areas were calculated on muscles harvested before the animals were killed. There was a nonsignificant trend toward stronger contraction in the NMP group, but NMP fibers were significantly larger than those in DNI and control groups (p less than 0.001).

Animals↗