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Biomedical subjects

H Klein

Publications and source records attributed to H Klein.

At least 73 records · Page 4Linked to original sources
PubMed1999

The acceptability of the female condom among substance-using women in Washington, DC.

This research is based on structured interviews, semi-structured interviews, and informal firsthand observation of women residents of Washington, DC who used crack and/or injected drugs during the previous 30 days. The study entailed introducing these women to the female condom, exposing them to an HIV risk reduction intervention teaching them how to use it and how to negotiate its use with their sexual partner(s). Women were tested for HIV and asked to return one week later for their results. They were asked to try the female condom within that first week. Upon returning for their tests results, ethnographers discussed with them their experiences with the female condom. They were reinterviewed for follow-up three months later to assess changes in behavior from baseline as well as their longer term experiences with and opinions of the female condom. The data presented in this paper are based on the interviews conducted one week after baseline. Of particular interest and concern to this research were: women's perceptions of the female condom prior to and subsequent to using it, women's partners' perceptions of the female condom after being introduced to it, and potential barriers to use. In all, 131 women, mostly African-American, took part in this study, which was conducted during the winter of 1997-1998.

Adult↗
PubMed1999

[Percutaneous dilatational tracheostomy].

BACKGROUND: Tracheostomy provides a method for long-term ventilation in intensive care, which reduces the risk of necrotizing lesions of the pharyngeal and laryngeal mucosa. Since the introduction of the percutaneous dilatational tracheostomy, experienced physicians are able to perform bedside tracheostomies. This presentation reviews the complication rate and long-term outcome of percutaneous dilatational tracheostomy. PATIENTS AND METHOD: The method was applied in 57 patients following previous orotracheal intubation averaging 7.8 days (3 to 15 days). Underlying diseases were sepsis/SIRS in 29, stroke in 7, cerebral hypoxemia after cardiopulmonary resuscitation in 10, trauma in 7, prolonged weaning in 2, primary neurological diseases in 2. RESULTS: The following complications occurred during the procedure: 1 major and 7 minor bleedings. 2 subcutaneous emphysemas, 1 mediastinal emphysema following tracheal injury. No complication required surgical intervention. In the follow-up 17 patients (30%) died from their underlying disease, none from complications of the tracheostomy. After removed of the tracheal tube, in 39 patients the stoma closed spontaneously within 7 to 14 days. In 8 patients the tracheostoma persisted for more than 3 months, but no clinically relevant tracheal stenosis was found. CONCLUSION: Percutaneous dilatational tracheostomy is a safe procedure easy to perform in intensive care units. Bronchoscopic control is necessary to avoid complications.

Dilatation↗
PubMed1998

Outcome after treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma.

BACKGROUND: Treatment of differentiated thyroid cancer has been studied for many years, but the benefits of extensive initial thyroid surgery and the addition of radioiodine therapy or external radiation therapy remain controversial. OBJECTIVE: To determine the relations among extent of surgery, radioiodine therapy, and external radiation therapy in the treatment of high-risk papillary and non-Hürthle-cell follicular thyroid carcinoma. DESIGN: Analysis of data from a multicenter study. SETTING: 14 institutions in the United States and Canada participating in the National Thyroid Cancer Treatment Cooperative Study Registry. PATIENT: 385 patients with high-risk thyroid cancer (303 with papillary carcinoma and 82 with follicular carcinoma). MEASUREMENTS: Death, disease progression, and disease-free survival. RESULTS: Total or near-total thyroidectomy was done in 85.3% of patients with papillary carcinoma and 71.3% of patients with follicular cancer. Overall surgical complication rate was 14.3%. Total or near-total thyroidectomy improved overall survival (risk ratio [RR], 0.37 [95% CI, 0.18 to 0.75]) but not cancer-specific mortality, progression, or disease-free survival in patients with papillary cancer. No effect of extent of surgery was seen in patients with follicular thyroid cancer. Postoperative iodine-131 was given to 85.4% of patients with papillary cancer and 79.3% of patients with follicular cancer. In patients with papillary cancer, radioiodine therapy was associated with improvement in cancer-specific mortality (RR, 0.30 [CI, 0.09 to 0.93 by multivariate analysis only]) and progression (RR, 0.30 [CI, 0.13 to 0.72]). When tall-cell variants were excluded, the effect on outcome was not significant. After radioiodine therapy, patients with follicular thyroid cancer had improvement in overall mortality (RR, 0.17 [CI, 0.06 to 0.47]), cancer-specific mortality (RR, 0.12 [CI, 0.04 to 0.42]), progression (RR, 0.21 [CI, 0.08 to 0.56]), and disease-free survival (RR, 0.29 [CI, 0.08 to 1.01]). External radiation therapy to the neck was given to 18.5% of patients and was not associated with improved survival, lack of progression, or disease-free survival. CONCLUSIONS: This study supports improvement in overall and cancer-specific mortality among patients with papillary and follicular thyroid cancer after postoperative iodine-131 therapy. Radioiodine therapy was also associated with improvement in progression in patients with papillary cancer and improvement in progression and disease-free survival in patients with follicular carcinoma.

Adenocarcinoma, Follicular↗
PubMed1998

Clinical efficacy of the wearable cardioverter-defibrillator in acutely terminating episodes of ventricular fibrillation.

The findings of our initial study demonstrate for the first time the ability to terminate induced VT/VF reliably (100% of all episodes) by a single, monophasic 230-J shock delivered by the Wearable Cardioverter-Defibrillator (WCD). Although limited by sample size, our data suggest the WCD could be used as a feasible bridge to definitive implantation of an implantable cardioverter-defibrillator in patients in whom risk stratification for sudden death is not completed.

Aged↗
PubMed1998

Fatty acid elongation in yeast--biochemical characteristics of the enzyme system and isolation of elongation-defective mutants.

Elongation of long-chain fatty acids was investigated in yeast mutants lacking endogenous de novo fatty acid synthesis. In this background, in vitro fatty acid elongation was dependent strictly on the substrates malonyl-CoA, NADPH and a medium-chain or long-chain acyl-CoA primer of 10 or more carbon atoms. Maximal activity was observed with primers containing 12-14 carbon atoms, while shorter-chain-length acyl-CoA were almost (octanoyl-CoA) or completely (hexanoyl-CoA, acetyl-CoA) inactive. In particular, acetyl-CoA was inactive as a primer and as extender unit. The Michaelis constants for octanoyl-CoA (0.33 mM), decanoyl-CoA (0.83 mM) lauroyl-CoA (0.05 mM), myristoyl-CoA (0.4 mM) and palmitoyl-CoA (0.13 mM) were determined and were comparable for fatty acid synthesis and elongation. In contrast, the affinity of malonyl-CoA was 17-fold lower for elongation (Km = 0.13 mM) than for the fatty acid synthase (FAS) system. With increasing chain length of the primer (> or = 12:0), fatty acid elongation becomes increasingly sensitive to substrate inhibition. Due to the activation of endogenous fatty acids, ATP exhibits a stimulatory effect at suboptimal but not at saturating substrate concentrations. In the yeast cell homogenate, the specific activity of fatty acid elongation is about 10-20-fold lower than that of de novo fatty acid synthesis. The same elongation activity is observed in respiratory competent and in mitochondrially defective cells. The products of in vitro fatty acid elongation are fatty acids of 15-17 or 22-26 carbon atoms, depending on whether tridecanoyl-CoA or stearoyl-CoA is used as a primer. In vitro, the elongation products are converted in part, by alpha-oxidation, to their odd-chain-length lower homologues or are hydrolyzed to fatty acids. In contrast, no odd-chain-length elongation products or very-long-chain fatty acids (VLCFA) shorter than 26:0 are observed in vivo. Hence, VLCFA synthesis exhibits a higher processivity in vivo than in the cell homogenate. In addition, the in vivo process appears to be protected against side reactions such as hydrolysis or alpha-oxidation. Yeast mutants defective in 12:0 or 13:0 elongation were derived from fas-mutant strains according to their failure to grow on 13:0-supplemented media. In vivo, 12:0 elongation was reduced to 0-10% of the normal level, while 16:0 elongation and VLCFA synthesis were unimpaired. It is concluded that yeast contains either two different elongation systems, or that the respective mutation interferes differentially with medium-chain and long-chain fatty acid elongation. The yeast gene affected in the elongation-defective mutants was isolated and, upon sequencing, identified as the known ELO1 sequence. It encodes a putative membrane protein of 32-kDa molecular mass with no obvious similarity to any of the known FAS component enzymes.

Acyl Coenzyme A↗
PubMed1998

Evaluating support services to seniors. A discussion of collaborative research.

The difficulties involved in attempting to turn collaboration into partnership are revealed in this article about the relationship between research funders and researchers, specifically government funders and university researchers. Some discussion revolves around the relationships between researchers and among the researchers, practitioners, and consumers. This article also discusses collaborative research relationships by using the evaluation of a support program to seniors as an illustration. Also addressed are how the research revealed the success of the program and the frustrations encountered when government would not act on the findings.

Aged↗
PubMed1998

Expression, purification, and biochemical characterization of a recombinant lectin of Sarcocystis muris (Apicomplexa) cyst merozoites.

The mature major microneme protein of Sarcocystis muris cyst merozoites, which is known as a dimeric lectin with high affinity to galactose and some of its derivatives, was expressed in Escherichia colias a histidine-tagged fusion protein. The recombinant polypeptide, which was recognized by a monoclonal antibody directed against the native lectin, was purified from inclusion bodies after solubilization and refolding, using a combination of metal chelate and lactose affinity chromatography. The apparent molecular mass of the refolded polypeptide as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoreses was 16 kDa, whereas gel filtration chromatography clearly demonstrated that the recombinant protein, like its native counterpart, exists as a homodimer of two non-covalently associated subunits. Inhibition of haemagglutination suggests that the combining site of the recombinant lectin recognizes N-acetyl-galactosamine as the dominant sugar, thus confirming the correct folding of the monosaccharide combining site in the renatured lectin. To the best of our knowledge, this work represents the first reported detailed characterization of a recombinant lectin from apicomplexan parasites, and may contribute to a better understanding of the process of host cell recognition and invasion by these obligate intracellular protozoa.

Animals↗
PubMed1998

The effect of entering drug treatment on involvement in HIV-related risk behaviors.

The research described here is based on a sample of 8,241 out-of-drug-treatment users of injected drugs and/or crack, aged 18 or older, recruited from 22 sites across the United States and Puerto Rico. The study divided respondents into three groups-(a) cocaine or crack users who did not also use heroin or speedball (cocaine-only users), (b) heroin injectors who did not also use cocaine or crack or speedball (heroin injectors), and (c) users of cocaine or crack and injected heroin or speedball (dual users)--and compared the efficacy of entering drug treatment for these groups' involvement in HIV-related risk behaviors. The study found that entry into treatment corresponded to greater reductions in substance abusers' frequency of drug use and involvement in risky injection practices compared to those observed in people who did not enter treatment between their baseline and 6-month follow-up interviews. Entry into drug treatment was also associated with reductions in the practice of risky sexual behaviors, but these reductions were less substantial and less consistent than those noted for drug use and injection risk behaviors.

Cocaine-Related Disorders↗
PubMed1998

[Unilateral pulmonary vein atresia in early adulthood].

Unilateral pulmonary vein atresia is a rare condition in adults that may cause serious diagnostic problems because of unspecific clinical findings. A 28-year old female patient is described who presented with signs of recurrent pulmonary embolism with shortness of breathing, unilateral thoracic pain and several episodes of haemoptysis. Ventilation and perfusion scans showed a total lack of perfusion in the right lung with only slight disturbance of ventilation. However, no marked increase of pulmonary artery pressure and no signs of a recent thrombosis of peripheral veins were found. Transoesophageal echocardiography and pulmonary angiography in combination with aortography revealed the diagnosis of unilateral pulmonary vein atresia with abnormal branches of bronchial arteries. There is a considerably left-to-right shunt with return of flow from the bronchial arteries to the right and afterwards to the left pulmonary artery. Clinical, radiological and nuclear medical findings as well as therapeutical options are described.

Adult↗
PubMed1998

Diagnosis and treatment of bulimia nervosa.

Bulimia nervosa often has an obscure presentation that requires a high level of suspicion by physicians. Awareness of subtle signs and knowledge of important questions to pursue are critical to a physician's ability to diagnose this disorder. Since bulimia nervosa may have several comorbid psychiatric disorders, such as depression, substance abuse, and personality disorders, it is important to refer patients for further evaluation and treatment. The treatment of bulimia nervosa is comprehensive and individualized and may include cognitive-behavioral therapy, group therapy, family therapy, individual psychotherapy, pharmacotherapy, or hospitalization. The comorbid disorders must also be addressed with appropriate treatment such as a drug or alcohol rehabilitation program for substance abusers. Although the prognosis can be variable, the majority of bulimic patients have a serious chronic illness with remissions and exacerbations.

Adult↗
PubMed1997

Circadian variations of ventricular tachyarrhythmias detected by the implantable cardioverter-defibrillator.

OBJECTIVE: The purpose of this study was to prospectively evaluate the daily distribution of episodes of ventricular tachyarrhythmias triggering a last-generation ICD implanted in survivors of cardiac arrest not receiving any antiarrhythmic drug. BACKGROUND: Previous studies reported a circadian variation of out-of-hospital sudden cardiac arrest. Survivors of cardiac arrest and patients with sustained ventricular tachyarrhythmias have a higher risk of recurrence, but there is a lack of detailed information on the daily distribution of ventricular arrhythmia capable of precipitating the recurrence of a malignant ventricular event. METHODS: We used the data stored by a last-generation implantable cardioverter-defibrillator (ICD) to prospectively evaluate circadian distribution of ventricular tachyarrhythmias in 30 survivors of cardiac arrest, implanted with an ICD during an antiarrhythmic drug-free period. RESULTS: During a follow-up of 475 +/- 127 days, a total of 571 ventricular arrhythmias was recorded. Of these stored events, 39 episodes were ventricular fibrillation (VF), 428 events were ventricular tachycardia (VT) and the remaining 104 device activations were VTs spontaneously terminating before device therapy. A circadian variation (p < 0.001) of episodes of ventricular tachyarrhythmias was evident. The incidence of ventricular arrhythmias sharply increased at 6 a.m. and reached a maximum 4 hours later, after which there was a short decline and then a small peak between 3 p.m. and 5 p.m. With respect to different arrhythmias, VF or VTs with a cycle length < or = 350 msec demonstrated a circadian variation. Instead, VTs with a cycle length longer than 350 msec or spontaneously terminating before device discharge had a more even distribution throughout the day. In addition, most of the VF or VTs with a cycle length < or = 350 msec occurred within a few hours after awakening, which was not the case for VTs with a cycle length longer than 350 msec. CONCLUSIONS: The data of this study clearly show the existence of different circadian variations in the occurrence of ventricular tachyarrhythmias, suggesting complex interactions between the autonomic nervous system, ventricular electrophysiological properties and the onset of arrhythmia.

Adult↗