Young people's condom use: an event specific analysis.
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Biomedical subjects
Publications and source records attributed to D Rosenthal.
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The present study examined the rules used by 16-year-olds (n=191) to guide their behaviours during a sexual encounter. Boys and girls were asked about social rules for giving messages indicating that they did or did not wish to have sex, and strategies for encouraging or avoiding sex, together with the acceptability and usefulness of these strategies. They were also asked if they had used any of the strategies. A variety of rules were endorsed and young people found it easier to encourage than to discourage sex. There were few differences between boys and girls in their understanding of the rules but the relationships between acceptability, usefulness and actual use of a strategy varied according to gender. For the avoidance strategies the relationships were moderate but stronger for girls, whereas patterns of relationships were strong across all encouragement strategies and equally so for boys and girls. The findings are discussed in the context of divergence between these young people's rhetoric of equality and their lived reality.
Allergen content of extract derived from Alternaria is somewhat variable. Allergenic molecules from Alternaria that appear as differing molecular size bands on IgE probed immunoblots may have a great deal of sequence homology and differ only in the length of the amino acid chain. One method to study this problem is to produce recombinant proteins from Alternaria. To explore these possibilities, the following experiments were performed. A strain of Alternaria was grown on minimum salts and glucose in a fermentation container with constant stirring and aeration. Rapidly expanding mycelia were removed from the culture and mRNA was extracted. Purified mRNA was reacted with reverse transcriptase and an aliquot of first copy single strand DNA was enriched for the presence of DNA coding for an Alternaria allergen by PCR amplification. Modified DNA was then spliced into lambda gt11 phage and yielded a recombinant library with 10(5) PFU. The library was screened for the presence of allergenic proteins using IgE containing human sera from Alternaria-sensitive patients. Positive plaques were cloned. PCR analysis of positive clones using an oligonucleotide from the reported N-terminal sequence of Alt a1 indicated an insert of 295 base pairs. Sequence analysis yielded a reading frame containing 84 amino acid and confirmed that this segment contained the code for the reported N-terminal amino acid sequence of Alt a1. A computer search for this sequence found no homologous proteins in the Entrez sequences. Northern blotting studies on RNA purified from nine strains of Alternaria with the radiolabeled 247 BP DNA fragment indicated that this sequence was present in all strains. The 247 BP nucleotide was spliced into the Pflag vector and clones containing insert in the proper reading frame were identified. The presence of recombinant protein in the clones was verified by SDSPAGE time studies. Protein produced in time studies was shown by immunoblotting and sandwich EIA to bind human IgE from Alternaria sensitive patients. This recombinant protein, containing amino acid sequence for Alt a1, is bound by human IgE and therefore should be useful as a model for studying allergy to the native Alternaria glycoprotein. Further research should define where this sequence occurs in the Alternaria genome and should determine the sequence of the entire protein.
UNLABELLED: Laparoscopy for colonic diseases began in 1990 and has established a role in benign disease. Early observations and experiences demonstrated feasibility of laparoscopic surgery for a variety of colonic disease processes, but the applicability to colonic carcinoma was unclear. METHODS: In 1990, we began a comparative study of open (OCR) vs. laparoscopic (LCR) approach to colon cancer. The study progressed 65 months, with 224 patients in OCR group and 191 patients in LCR group. Parameters studied are stage, location, length of specimen, number of lymph nodes resected, margins, postoperative course, wound complications, recurrence rates, and immediate and long-term survival. OCR were standardized by one group, and LCR were standardized by a second group. All patients undergoing LCR were given freedom to choose either OCR or LCR, and informed consent was obtained. RESULTS: Equal or greater lymph node retrieval, resections, and distal margins were evident with LCR. Benefits with LCR were shown with shorter hospitalization (5.7 vs. 9.7 days), less blood loss, less wound problems (1 vs. 14), and quicker return of bowel function. Survival, recurrence, and death rates were essentially the same. There were no trocar implants in the LCR group. CONCLUSION: After five years, this study shows that laparoscopy does no harm to the patient, offers comparable oncologic resections, and seems to be patient-friendly, with less pain, quicker return of bowel functions, shortened hospitalization, and quicker return to full activity.
The hypercalciuria that eventually remains after the successful removal of a solitary parathyroid adenoma may originate from excessive intestinal calcium absorption, bone resorption or deficient renal reabsorption. In order to clarify this question, ten patients surgically cured from primary hyperparathyroidism (PHPx), ten age-matched normal subjects and five nephrolithiasic patients with renal hypercalciuria (RH) were studied after five days on a low calcium diet, either during fasting or after oral calcium load. Fasting serum calcium, amino-terminal and intact PTH levels and also urinary cAMP excretion were normal in every individual patient. Serum ionized calcium and inulin clearance (GFR) were used for calculations of the filtered load (FL Ca) and the fractional excretion of calcium (FE Ca). Six PHPx patients displayed fasting calciuria above the upper limit calculated for control subjects, despite having the lowest GFR and FL Ca (p < 0.05 vs control). These patients (h-PHPx) had a small calciuric response to oral calcium load. Serum 1,25-(OH)2D3 and 25OHD3 did not correlate with calciuria. Our findings exclude intestinal hyperabsorption and excessive bone resorption in h-PHPx patients, and strongly suggest a renal tubular defect in calcium reabsorption as the cause of their hypercalciuria. This defect could be primary, as in RH, but only three hPHPx patients had recurrent kidney stones before surgery. On the other hand, as a negative correlation between GFR and FE Ca was only found in PHPx patients, it seems probable that the disturbances in glomerular and tubular functions were secondary to the long standing hypercalcemic hyperparathyroidism.
Some alterations in hypothalamo-pituitary-thyroid axis occur during aging. In this study we evaluated the changes induced by aging in pituitary and thyroid iodothyronine-deiodinase (DI) activities, and in serum T4, T3 and TSH. Groups of 6-18 female Dutch-Miranda rats aged 3-5 months (young adults) were studied in parallel with similar groups of old (10-12 months) and senescent (24-30 months) animals. DI activities were determined in the microsomal fraction of pooled pituitary or thyroid glands (6 glands per pool), using T4 as substrate and DTT as cofactor; the T3 formed was measured by specific radioimmunoassay. Serum T3, T4 and TSH were measured by specific radioimmunoassays. Serum T4 was significantly decreased in both groups of aged rats, but serum TSH was unaffected. Serum T3 was just slightly decreased in the senescent rats. Total pituitary DI activity was significantly decreased in the aged rats (10-12 and 24-30 months). Both type I and type II DI activities were affected, although the decrease in type I DI only became significant in the senescent rats. In contrast, to its effect in the pituitary, aging does not decrease, even slightly, the DI activity in the thyroid gland. The thyroid DI activity may contribute to the unaltered serum T3 levels found in aged rats in the present study.
In an attempt to obviate the need for an incision the length of the leg during in situ saphenous vein bypass, a minimally invasive operation using 'laparoscopic techniques' was developed. At operation, standard incisions were made over the proximal femoral artery/vein and the saphenous vein at the distal popliteal artery level. An angioscopic valvulotome was used to perform valvulotomy under direct vision. After valvulotomy, a distention balloon system was used to form a 'pocket' into which a laparoscope was inserted. Trocars were then inserted under direct vision and the saphenous vein dissected and side branches individually clipped. After occlusion of the venous side branches, proximal and distal arterial anastomoses were performed in the standard fashion. This minimally invasive operation using laparoscopic techniques precludes the need for a long leg incision and saphenous vein dissection, except at the proximal and distal arterial anastomoses.
PURPOSE: Recurrent carotid stenosis after carotid endarterectomy has been extensively reported. The occurrence, however, of another ipsilateral restenosis that requires a third carotid operation is rare. The purpose of this study was to evaluate possible risk factors and the most efficacious management of the patient with "secondary" recurrent carotid stenosis. METHODS: A survey of the Southern Association for Vascular Surgery was performed, and 31 patients who had had surgery for secondary recurrent carotid stenosis were identified. RESULTS: The mean interval between the recurrent stenosis operation and secondary recurrent carotid stenosis was 39.8 months (range, 9 to 83 months). At the third operation, 21 patients underwent carotid patch angioplasty and 10 underwent carotid resection with an interposition saphenous vein graft. No postoperative strokes or deaths occurred; three patients (10%) had a peripheral nerve injury. Nine early (< 24 mo) secondary recurrent carotid stenoses occurred, and these patients underwent patch angioplasty. Twenty-three female, cigarette-smoking patients and 20 patients with elevated lipid levels had early restenosis and were identified as being at high risk for the development of another stenosis. A fourth significant stenosis developed in five of these high-risk patients who had saphenous vein patch angioplasty at their third carotid operation; eight other high-risk patients had carotid resection with an interposition saphenous vein graft, and no other stenosis developed. CONCLUSION: Patients who have secondary recurrent carotid stenoses can safely undergo a third carotid operation. Female habitual smokers with elevated lipid levels and an early restenosis appear to be at high risk of secondary recurrent carotid stenoses. When surgery is necessary, carotid resection with an interposition saphenous vein graft appears more durable than patch angioplasty.
Initiation into injecting is a crucial event for continued reproduction of an injecting drug using (IDU) population and for exposure to blood-borne viruses, but little is known about how this happens. Three hundred young injectors were interviewed in Melbourne by peer workers within the first few years of beginning to inject, about the circumstances surrounding their initiation. Most had indications of social disruption, including having left school early, unemployment, family disruption, homelessness and incarceration. First drug injected was most often amphetamines (average age 16 years), most having already used amphetamines by a different route of administration, but with a steady movement thereafter to heroin as the drug of choice. The most common scenario was one in which injecting was unplanned but the person was active in bringing about the initiation. Most identified a significant other who initiated them (few of whom were dealers), and over half had subsequently initiated others into injecting, on average 0.6 per year; after 5 years 237 young injectors had initiated at least 420 others. Those who initiated multiple others were more likely to be unemployed, to inject multiple drugs and to have dealt. Modelling injecting as a communicable phenomenon, where appropriate, may help estimate population dynamics among IDUs. Peer education programmes are likely to be the most effective harm reduction approach among new injectors.
The juxtaposition of pleasure and danger has engaged many feminist theorists and researchers in the field of sexuality. This article presents a theoretical analysis of the ambiguous and complex relationship between 'pleasure', 'danger' and contemporary feminist theory. In doing so, it offers an understanding of the ways in which the categories of pleasure and danger operate within the discourses of heterosexuality to construct perceptions of risk in the context of HIV/AIDS. Data were collected from a study of the sexual attitudes and practices of 112 sexually-active, single, heterosexual adults (58 men and 54 women), aged 20 to 40 years (mean = 27 years) who agreed to be interviewed when approached at night-clubs and public "singles' bars around Melbourne, Australia. The qualitative analysis presented here is consistent with a poststructuralist feminism. First, we discuss how sexuality cannot be cast solely as pleasurable or dangerous. Second, we demonstrate how heterosexualized notions of pleasure and danger operate to provide misperceptions of risk from HIV/AIDS transmission. Third, we identify the ways in which the logic of identity functions to obscure risk within the discourse of heterosexuality, and finally we attempt to forge new ways of practising pleasure which disrupt heterosexist discourses and allow for pleasures which incorporate danger.
A video-assisted thoracoscopic microsurgical approach was developed in the laboratory and subsequently used clinically to resect abnormalities of the thoracic vertebrae, to decompress the thoracic spinal cord, and to reconstruct the thoracic vertebral bodies. This report describes the development of the clinical operative techniques for microsurgical thoracoscopic vertebrectomy, neural decompression, and spinal reconstruction. This minimally incisional approach was clinically used in 17 patients to treat vertebral osteomyelitis, tumors, and compression fractures. Microsurgical thoracoscopic techniques were performed using several narrow, flexible, working portals placed in small incisions in the intercostal spaces. Access to the thoracic spine was achieved through the pleural cavity after temporary deflation of one lung using a double-lumen endotracheal tube. The parietal pleura, segmental vessels, and rib heads were dissected off the surfaces of the involved vertebrae to expose the region of interest. Long narrow spine dissection tools were used to perform the spinal decommpression and reconstruction. This technique achieved the same amount of spinal dissection as that achieved with conventional open spinal procedures and used microsurgical visualization techniques. The small incisions with reduced soft tissue dissection may reduce postoperative pain, shorten the length of hospitalization, and have cosmetic and functional advantages. Thoracoscopic vertebrectomies and reconstruction of the spine were technically feasilble procedures that were performed with excellent clinical results. This minimally incisional technique provides a viable alternative to thoracotomy or to posterolateral approaches for thoracic vertebrectomy and vertebral body reconstruction.
It is well accepted that the treatment of spinal tumors that threaten neurological integrity comprises resection, vertebral body reconstruction, and stabilization if the patient's condition is suitable. In spite of the excellent results reported using thoracotomy, the majority of investigators recommend posterolateral techniques because of lower morbidity, shorter hospitalization time, and the possibility of performing dorsal stabilization via the same incision. To overcome some of the disadvantages of thoracotomy, the authors developed an anterior procedure that permits vertebrectomy, reconstruction, and stabilization to be performed entirely by endoscopic technique. Microsurgical endoscopy and stabilization were performed in four patients with metastatic disease of the thoracic spine. All were ambulatory after surgery and at follow up; preoperative neurological and neurophysiological deficits improved as well. No complications occurred in this small series. Microsurgical endoscopy achieves a substantial reduction in trauma, use of analgesic medications, and hospitalization time. Early results seem to indicate that adequate decompression, stabilization and reduction of surgical morbidity can be achieved with this technique.
Thyroid hormones have profound effects on growth and development. In the brain L-3,5,3'-triiodothyronine (T3), the bioactive hormone, is involved with the harmonious development acting in neuronal and glial cell differentiation. T3 acts on the cells by interacting with nuclear receptors that can regulate the expression of several genes. Astrocytes also show receptors to the hormone. We reported herein data on the effects of T3 on astrocytes. We have verified that T3 has a morphological effect on cultured cortical astrocytes with rearrangement of GFAP filaments, and induces proliferation in the cultured cerebellar astrocytes of newborn rats. We discuss here the effects of T3 on astrocytes, considering the possibility that thyroid hormone prepares the astrocytes to interact with neurons.
Sphingosylphosphocholine (SPC) is the deacylated derivative of sphingomyelin known to accumulate in neuropathic Niemann-Pick disease type A. SPC is a potent mitogen that increases intracellular free Ca2+ and free arachidonate through pathways that are only partly protein kinase C-dependent. Here we show that SPC increased specific DNA-binding activity of transcription activator AP-1 in electrophoretic mobility-shift assays. Increased DNA-binding activity of AP-1 was detected after only 1-3 min, was maximal after 6 hr, and remained elevated at 12-24 hr. c-Fos was found to be a component of the AP-1 complex. Northern hybridization revealed an increase in c-fos transcripts after 30 min. Since the increase in AP-1 binding activity preceded the increase in c-fos mRNA, posttranslational modifications may be important in mediating the early SPC-induced increases in AP-1 DNA-binding activity. Western analysis detected increases in nuclear c-Jun and c-Fos proteins following SPC treatment. SPC also transactivated a reporter gene construct through the AP-1 recognition site, indicating that SPC can regulate the expression of target genes. Thus, SPC-induced cell proliferation may result from activation of AP-1, linking signal transduction by SPC to gene expression. Since the expression of many proteins with diverse functions is known to be regulated by AP-1, SPC-induced activation of AP-1 may contribute to the pathophysiology of Niemann-Pick disease.
The effects of triiodothyronine (T3) on cell morphology were examined in cerebral hemisphere and cerebellar astrocyte cultures obtained from normal and hypothyroid neonatal rats. T3-treatment induced morphological changes in astrocytes from cerebral hemispheres. This morphological effect was produced earlier if astrocytes were treated with conditioned medium obtained from cerebral hemisphere astrocyte cultures previously exposed to 50 nM T3. T3 or conditioned medium-treatment produced faster morphological changes in hypothyroid rat cerebral hemisphere astrocyte monolayers. Cerebellar astrocytes from normal brain did not respond to thyroid hormone with morphological changes, but proliferated after T3-treatment. However, hypothyroid cerebellar astrocyte cultures exhibited morphological changes, differently than normal cells. We verified that T3 may induce astrocyte secretion of factor(s) that promotes morphological differentiation in cerebral hemisphere astroglial cultures and stimulates the proliferation of cerebellar astrocytes. Astrocytes obtained from hypothyroid animals were more sensitive to secreted factors than normal cells. These results emphasize the heterogeneity and the importance of glial cells to normal brain development and open new questions about thyroid hormone therapy in hypothyroidism.
OBJECTIVE: To measure the anatomic and physiologic changes in the synovium of patients with active rheumatoid arthritis (RA) before and after the initiation of treatment with low-dose systemic glucocorticoids and methotrexate (MTX). METHODS: Two patients with RA with active synovitis involving the carpus were evaluated by imaging parameters at baseline and again after 14 weeks (of treatment with low-dose prednisone and MTX). Standard clinical parameters, laboratory measurements, and contrast-enhanced magnetic resonance imaging (MRI) (synovial volume estimate) and positron emission tomography (PET) with 18F-fluoro-2-deoxyglucose (18-FDG) (synovial metabolism estimate) were performed. RESULTS: Compared with baseline, standard clinical parameters (i.e., joint count, joint index, morning stiffness, global assessments of arthritis activity, and erythrocyte sedimentation rate) improved dramatically in both patients after treatment with low-dose prednisone and MTX. In concert with this trend, the synovial volume of the affected wrist was reduced by 60%, and 76% and the metabolism of 18-FDG was reduced by 66% and 69% in the 2 patients. CONCLUSION: These preliminary observations indicate that a volumetric estimate of inflamed synovium (using contrast-enhanced MRI) and quantification of synovial deoxyglucose metabolism (using PET) are technically feasible and, in the 2 reported cases, correlate well with standard outcome measures. These imaging modalities may provide new objective parameters to determine RA disease activity and effectiveness of antirheumatic medications; however, the potential clinical utility of these measures remains to be defined.
Laparoscopic colon resection (LCR) has been performed in the United States sine 1990. This procedure has been accepted by many as a reasonable alternative for nonmalignant, colonic, surgical disease, but the laparoscopic approach remains controversial for curative treatment of carcinoma. In this paper, the results of a nonrandomized series of two large experiences of laparoscopic colon resections were performed and followed for 3 1/2 years in a prospective fashion against an equal number of patients who underwent open resection. The setting was several large metropolitan hospitals in San Antonio, Texas. Over 194 patients were involved in this study. Each patient once diagnosed with resectable colonic cancer was allowed to choose their own procedure, laparoscopic or open colon resection, either of which was performed by the authors. Factors considered include age, sex, body habitus, stage of cancer, margins of resection, numbers of lymph nodes retrieved, hospitalization time, and follow-up period. Observations at this time indicate the following: (1) LCR allows for resection comparable to the classical approach, (2) equal numbers of mesenteric lymph nodes can be retrieved, (3) adequacy of margins of resection can be accurately determined by colonoscopy during LCR, and (4) brief follow-up periods show comparable survival and disease-free intervals. It is the conclusion of the authors that with proper training LCR will come to be recognized as a safe, effective surgical option for treatment of selected patients with colon cancer.
Inflow control of a rapidly expanding or ruptured femoral anastomotic "pseudoaneurysm" can be fraught with hazard. Occlusion of an anastomotic femoral aneurysm with a balloon catheter offers the surgeon a simple method of gaining inflow control prior to surgery. After achieving inflow control with the balloon catheter, the surgeon can incise the anastomotic aneurysm without significant blood loss, control back bleeding with balloon occlusion catheters, and with relative ease and safety repair or replace the anastomotic aneurysm as indicated. An illustrative case is presented.