Coronary artery stenting postcardiac transplant: a report of two cases

Coronary atherosclerosis remains a significant cause of morbidity and mortality following cardiac transplantation. Coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, and directional coronary atherectomy have all been presented as attempted treatment options in this population with generally suboptimal results. Endovascular stenting is a new transcatheter treatment modality with unique potential advantages as compared to other transcatheter revascularization techniques. This report presents the use of endovascular stenting and 6-mo follow-up in two orthotopic cardiac transplant recipients with proximal stenotic posttransplant graft atherosclerosis.

Renal nerve responses to somatic nerve activation in stroke-prone spontaneously hypertensive rats

In chloralose/urethane anaesthetised stroke-prone spontaneously hypertensive rats, blood pressure and integrated renal nerve activity were higher whereas heart rate was lower than in Wistar rats by 37, 146 and 11%, respectively (all P < 0.001). The renal nerve signal was subjected to fast Fourier transformation to generate power spectra. In the hypertensive rats, total spectral power was 400% (P < 0.01) and power at the heart rate frequency was 50% (P < 0.01) greater while phase and time differences were shorter (both P < 0.001) than in Wistar rats. Brachial nerve stimulation increased total power in Wistar and hypertensive rats (P < 0.05), but importantly, power at the heart rate frequency was decreased by 80% in Wistar whereas there was a 20% (P < 0.05) increase in hypertensive rats, while phase and time differences were raised only in hypertensive rats (P < 0.05). Bilateral cervical vagotomy of the hypertensive rats had minimal actions on most variables but phase and time differences were doubled compared to intact hypertensive animals, but brachial nerve stimulation decreased power at the heart rate frequency (P < 0.05) which was a very different response from intact rats. Resting blood pressure, heart rate, total power and power at the heart rate frequency in the carotid sinus denervated animals were lower than in intact hypertensive rats, between 17 and 71%, respectively, but increased during brachial nerve stimulation. These experiments demonstrated that whereas somatic sensory input can modulate the pattern of sympathetic nerve activity to the kidney under normal conditions, this does not occur in the hypertensive rat. This appears to be related to afferent information carried by the vagus which suppresses the normal response; the carotid sinus baroreceptors are devoted to organising the nerve activity in relation to the blood pressure pulse wave.

Nonvalvular myocardial involvement in metastatic carcinoid disease

A patient with the unusual post mortem finding of myocardial metastatic carcinoid tumour without classical valvular or endocardial carcinoid disease is described. This rare occurrence may represent an aggressive type of carcinoid tumour, with metastatic disease occurring before the development of classical fibrous valvular and endocardial pathology.

Identification of a new antifungal target site through a dual biochemical and molecular-genetics approach

The target site of the antifungal compound LY214352 [8-chloro-4-(2-chloro-4-fluorophenoxy) quinoline] has been identified through a dual biochemical and molecular-genetics approach. In the molecular-genetics approach, a cosmid library was prepared from an Aspergillus nidulans mutant that was resistant to LY214352 because of a dominant mutation in a single gene. A single cosmid (6A6-6) that could transform an LY214352-sensitive strain of A. nidulans to LY214352-resistance was isolated from the library by sib-selection. Restriction fragments from cosmid 6A6-6 containing the functional resistance gene were identified by transformation, and sequenced. The LY214352-resistance gene coded for a protein of 520 amino acids that had a 34% identity and a 57% similarity in a 333 amino-acid overlap to E. coli dihydroorotate dehydrogenase (DHO-DH). The results of a series of biochemical mechanism-of-action studies initiated simultaneously with molecular-genetic experiments also suggested that DHO-DH was the target of LY214352. Assays measuring the inhibition of DHO-DH activity by LY214352 in a wild-type strain (I50=40 ng/ml) and a highly resistant mutant (I50>100 microgram/ml) conclusively demonstrated that DHO-DH is the target site of LY214352 in A. nidulans. Several mutations in the DHO-DH (pyrE) gene that resulted in resistance to LY214352 were identified.

Articulation strut coronary restenosis in Palmaz-Schatz stents

We describe articulation strut coronary restenosis in two patients with Palmaz-Schatz 153 stents and discuss its aetiology, management and possible prevention.

Balloon mitral valve dilatation as an aid to weaning from ventilatory support in patients with intractable pulmonary oedema caused by severe mitral stenosis

Intractable pulmonary oedema in patients undergoing mechanical ventilation must be investigated as older patients with severe mitral stenosis can be rescued by balloon dilatation of the mitral valve, thus enabling elective cardiac surgery at reduced risk. We describe two such cases and discuss the role of transoesophageal echocardiography in the intensive care unit in the diagnosis and management of these patients.

Beta 2-adrenoceptor densities do not correlate with growth, carcass quality, or meat quality in cattle

Drugs that activate beta 2-adrenoceptors (beta-agonists) are known to have profound effects on growth, body composition, and meat quality. Physiologically, these adrenoceptors are activated and regulated by the hormone adrenaline. Because the response to a drug or hormone is dependent partly on the density of the tissue receptors, the potential for predicting growth, carcass quality, or meat quality from knowing beta 2-adrenoceptor density in three disparate sample sites in cattle was examined. Cell membrane fragments were prepared using samples of longissimus muscle, semitendinosus muscle, or ear obtained within 30 min of death from 48 steers. Beta 2-Adrenoceptor density (Bmax) was measured in these membrane preparations by saturating them with the radioligand [125I]iodocyanopindolol. There was no correlation between Bmax values measured in ear samples, longissimus muscles, or semitendinosus muscles. Bmax measured in samples of ear did not correlate with any growth or carcass traits, including weight gain, carcass weight, fat depth, or eye muscle area. Bmax measured in longissimus muscle only correlated weakly with meat color, and Bmax measured in semitendinosus muscle only correlated with carcass weight. We conclude that beta 2-adrenoceptor density is not a useful predictor of growth, carcass quality, or meat quality in cattle.

Clinical characteristics of black asthmatic children

A prospective study of 455 black asthmatic children (277 boys) attending the Baragwanath Hospital asthma clinic was undertaken. A history was obtained by means of a standardised questionnaire and skin tests were performed. Cough was the commonest presenting symptom and upper respiratory tract infections, exercise and cold weather the commonest symptom precipitants. The relative incidences of the other precipitants reflected the environment of the study population. Associated atopic conditions were present in 75.5% of patients and a family background in 22.2%. Other respiratory diagnoses were commonly made, particularly tuberculosis, which was diagnosed in 7.4%. Fewer than one-third had no positive skin reaction. The commonest allergens were grasses, pollen and house-dust mites. The high proportion of house-dust mite sensitivity (44.2%) contradicts beliefs that they are rare at higher altitudes.

Renal sympathetic nerve responses to somato-sensory nerve stimulation in normotensive rats

Blood pressure, heart rate and renal sympathetic nerve activity were recorded in groups of chloralose/urethane-anaesthetised intact, vagotomised and carotid sinus denervated Wistar rats before and during bilateral somatic afferent nerve stimulation from 0.1 to 3.2 Hz. Renal sympathetic nerve activity was subjected to power spectral and cross correlation analysis. Haemodynamic and integrated renal nerve responses to graded brachial nerve stimulation were not altered by either bilateral vagotomy or carotid sinus denervation and total power of the spectra, from 0-10 Hz, was similar in each group. The percentage power peak at heart rate in intact rats decreased with increasing stimulus frequency, from a control value of 19.2 +/- 1.9% to a minimum of 2.8 +/- 0.7% at 1.6 Hz, while coherence and phase were not altered. Conversely, the peak at the stimulus frequency rose with increasing stimulus frequency reaching 35.3 +/- 2.0% at 3.2 Hz. In the vagotomised group, power at heart rate was significantly lower at each stimulus frequency compared to intact rats although coherence was similar and the phase difference was larger. The peak power at stimulus frequency, coherence and phase difference were similar to those obtained in the intact rats. In the carotid sinus denervated rats, the percentage power at heart rate, coherence and phase difference were significantly smaller than in intact rats. The peak at the stimulus frequency and the phase difference were similar to those obtained in the intact rats whereas coherence was lower. These findings demonstrate that the pattern of renal nerve activity can be changed from one modulated by the baroreceptor to one driven by somatic afferent nerve activity. The vagus appears to play a minor role in the overall pattern of renal nerve activity with the primary controller being the carotid sinus baroreceptors. The data also show that the renal nerve response to somatic afferent nerve stimulation is independent of the afferent nerve input arising from either the atrial or the carotid sinuses.

HIV prevention beliefs among urban African-American youth

PURPOSE

This study investigates specific beliefs related to prevention of AIDS and HIV infection among African-American teenagers.

METHODS

This study administered valid and reliable measures of HIV/AIDS risk knowledge and prevention beliefs to 150 African-American teenagers. Demographic and psychosocial data were gathered.

RESULTS

Black teenagers respond in socially acceptable and undesirable ways and this ambivalence can be explained within the theory of reasoned action. These teens simultaneously believed in the importance of safe sex behaviors while expressing doubt about the viability of some safe sex behaviors. Females demonstrated higher self-efficacy and self-control beliefs while males were more likely to endorse culturally loaded suspicious beliefs about AIDS contraction and transmission.

CONCLUSIONS

Those teenagers who perceived themselves as highly knowledgeable scored lower on reliable AIDS Knowledge and Prevention Beliefs measures than those who claimed moderate AIDS knowledge. Some of these "Know It All" teenagers may reflect a subculture of pseudo-confidence that requires special interventions.

B7-1 expression decreases tumorigenicity and induces partial systemic immunity to murine neuroblastoma deficient in major histocompatibility complex and costimulatory molecules

Neuroblastoma may escape an immune attack by virtue of its low expression of surface accessory molecules essential in the antitumor response. Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector LB7-1SN to examine the influence of B7-1 expression on the immune response directed against a low major histocompatibility class (MHC) I and class II negative, B7-2, and ICAM-1 negative tumor. Using a retroperitoneal model for implantation of neuroblastoma in its natural site, we demonstrated that expression of B7-1 by neuro-2a reduces its tumorigenicity. Coinjection of B7-1-positive and -negative cells improved survival compared with mice receiving B7-1-negative cells alone. This was dependent on the ratio of B7-1+ to B7-1- neuro-2a cells injected. CD8+ and not CD4+ T-cell depletion significantly increased tumor-induced mortality in syngeneic A/J mice, indicating that B7-1 decreases tumorigenicity primarily by direct constimulation of CD8+ T cells. Rejection of N-2a/B7-1 tumors or preimmunization with irradiated N-2a/B7-1 cells die not increase protection to challenge with unmodified neuro-2a cells over mice vaccinated with N-2a/neo. Furthermore, cytotoxic T lymphocyte (CTL) precursor frequencies were not significantly higher after in vivo priming and in vitro stimulation with irradiated N-2a/B7-1 compared with N-2a/neo, indicating that B7-1 costimulation by the tumor, in the absence of adequate antigen presentation by MHC molecules, may limit the generation of effective CTLs.

Failure of high-dose oral acyclovir to suppress CMV viruria or induce ganciclovir-resistant CMV in HIV antibody positive patients

Ninety-three symptomatic HIV antibody positive patients were randomized to receive zidovudine (ZDV) 600 mg/day and acyclovir (ACV) 4,800 mg orally per day versus ZDV 600 mg/day plus placebo. Urine was obtained at 3-month intervals and cultured for cytomegalovirus (CMV) in diploid fibroblast cells. The percent of urine specimens positive for CMV was 7.1% in the ZDV group and 5.8% in the ZDV plus ACV group (p = 0.55); 27% of patients had at least one urine culture positive for CMV while taking ZDV, versus 20% of patients taking the combination of ZDV plus ACV (p = 0.52). We conclude that ACV at a dosage of 4,800 mg/day does not suppress CMV excretion in urine of symptomatic HIV antibody positive patients taking concurrent ZDV. Use of ACV did not appear to induce resistance of CMV to ganciclovir since the ID50 of isolates from the two treatment groups did not differ.

Somatosensory regulation of renal function in the stroke-prone spontaneously hypertensive rat

1. Chloralose-urethane-anaesthetized Wistar rats and stroke-prone spontaneously hypertensive rats (SHRSP) were prepared for measuring renal function. 2. Bilateral brachial nerve stimulation for 15 min, at 1.3 Hz (15 V, 0.2 ms), increased blood pressure from 119 +/- 2 to 151 +/- 6 mmHg (P < 0.01) in Wistar rats and from 181 +/- 6 to 203 +/- 6 mmHg (P < 0.05) in SHRSP; renal perfusion pressure was mechanically regulated at prestimulus levels but renal blood flow (4.1 +/- 0.7 ml min-1 g-1 in Wistar rats and 3.4 +/- 0.3 ml min-1 g-1 in SHRSP) and glomerular filtration rate (1.18 +/- 0.09 ml min-1 g-1 in Wistar rats and 0.88 +/- 0.01 ml min-1 g-1 in SHRSP) decreased between 5 and 30% (P < 0.05-0.001). 3. During brachial nerve stimulation, urine flow (13.8 +/- 2.2 microliters min-1 g-1) and absolute and fractional sodium excretion (3.70 +/- 0.64 mumol min-1 g-1 and 2.06 +/- 0.23%) decreased by 60-70% in the Wistar rats (P < 0.01-0.001) and the responses were unaffected by vagotomy or carotid sinus denervation. In the SHRSP, urine flow rate (9.74 +/- 2.52 microliters min-1 g-1) and absolute and fractional sodium excretion (1.98 +/- 0.59 mumol min-1 g-1 and 1.41 +/- 0.28%) decreased by 15-30% (P < 0.05-0.01), decreases which were significantly (P < 0.05) smaller than those observed in the Wistar rats. Moreover, the responses were some 40-60% larger in the vagotomized and carotid sinus-denervated SHRSP. 4. The influence of vagal and carotid sinus afferent nerves on the somatosensory-induced renal responses in the Wistar rats was small, whereas in the SHRSP they appeared to exert a marked tonic inhibitory effect. It is concluded that there is excessive baroreceptor restraint on neural regulation of renal function in the SHRSP.

Cytogenetic studies in endometriosis tissue

We analyzed 45 pelvic endometrial implants from 42 patients between the ages of 14 and 40 years to investigate whether cytogenetic abnormalities were present in these samples. Chromosomal abnormalities have been described in benign tumors of the female genital tract, such as uterine leiomyomas and endometrial polyps. Furthermore, heritable factors have been postulated to influence a woman's susceptibility to develop endometrial tissue implants outside the uterine cavity. To study whether these factors result in or are associated with chromosomal changes, endometriosis cells were analyzed cytogenetically after short-term culture. No consistent chromosome abnormalities were observed in any of the cases analyzed.

Corneal astigmatism induced by superior versus temporal corneal incisions for extracapsular cataract extraction

PURPOSE

We tested the hypothesis that superior corneal sections induce a shift to 'against-the-rule' astigmatism and temporal corneal sections lead to the preferred 'with-the-rule' astigmatism.

METHODS

We conducted a prospective randomised trial of superior versus temporal corneal incisions in extracapsular cataract surgery in a hospital practice. Thirty nine eyes of 37 patients were included. The induced astigmatism was analysed by three methods.

RESULTS

When analysed by Cravy's method of induced astigmatic cylinders, the superior incision induced a greater degree of 'with-the-rule' astigmatic cylinder prior to sutures removal on day 77 (P < 0.049). Long term, the temporal incision produced 1.44 dioptre of 'with-the-rule' astigmatism, while the superior section produced 0.08 dioptre of 'against-the-rule' astigmatism (P < 0.001).

CONCLUSION

The results of this small trial indicates that the superior corneal incision produces significantly less astigmatism than the temporal incision. The temporal incision induces a moderate degree of 'with-the-rule' astigmatism.

Parallel detection of Kanizsa subjective figures in the human visual system

Subjective figures, seen in the absence of luminance gradients (Fig. 1), provide a phenomenal illusion that can be related to the properties of single cells in the visual cortex, offering a rare bridge between brain function and visual awareness. It remains controversial whether subjective figures arise from intelligent cognitive mechanisms, or from lower-level processes in early vision. The cognitive account implies that the perception of subjective figures may require serial attentive processing, whereas on the low-level account they should arise in parallel at earlier visual stages. Physiological evidence apparently fits a low-level account and indicates that some types of subjective contour may be detected earlier than the conventional Kanizsa type. Here we report that even Kanizsa subjective figures can be detected without focal attention at parallel stages of the human visual system.

Processing of the pre-beta-amyloid protein by cathepsin D is enhanced by a familial Alzheimer's disease mutation

A major pre-beta-amyloid protein695 (APP695) processing activity from Alzheimer's disease brain extracts was identified and found to be indistinguishable from the activity of cathepsin D.APP695 processing activity cleaved APP695 into a series of fragments that reacted on immunoblots to a monoclonal antibody (C286.8a) against beta-amyloid-(1-7)-peptide and cleaved N-dansyl-APP-(591-601)-amide at the Glu-Val and Met-Asp bonds. Fragments of 5.5 kDa and 10-12 kDa were formed from the cleavage of APP695 by cathepsin D at the Glu593-Val594 bond, and had the same N-terminus as a minor form of beta-amyloid released by cells. The Lys595-->Asn and Met596-->Leu substitutions found in a pedigree of familial Alzheimer's disease, increased the cathepsin D-catalyzed rate of accumulation of 5.5 kDa and 10-12 kDa C286.8a-reactive fragments 5-10fold. This substitution also increased the rate of N-dansyl-APP-(591-601)-amide cleavage at the Xaa-Asp bond by up to 41-fold. These observations suggest a role of cathepsin D in beta-amyloid formation under certain circumstances.

Baroreceptor and somatic sensory regulation of kidney function in two-kidney, one-clip Goldblatt hypertensive rats

The aim of this investigation was to characterize the renal haemodynamic and tubular responses to somatic afferent nerve stimulation following the removal of afferent nerve input from the atria or the carotid sinuses in chloralose-urethane-anaesthetized Sprague-Dawley rats and two-kidney, one-clip Goldblatt hypertensive rats. Bilateral stimulation of the brachial nerve plexi at 15 V, 1.3 Hz for 0.2 ms resulted in an increase in systemic blood pressure in each group of 10-40%, while renal perfusion pressure was maintained at a constant level. There were significantly larger falls in left renal blood flow and combined left and right glomerular filtration rate in all groups following selective denervation of either the cardiopulmonary or the carotid sinus baroreceptors, respectively. Brachial nerve stimulation decreased urine flow rate and absolute and fractional sodium excretion from both kidneys in Sprague-Dawley intact animals by 53, 65 and 59%; in vagotomized animals by 68, 77 and 63%; and in carotid sinus denervated animals by 86, 90 and 48%, respectively. The renal response in the Goldblatt group were similar to the normotensive group, but the main contribution of the total response was from the untouched left kidney. The inhibitory influence of the vagus and carotid sinuses on the renal sympathetic nerve-mediated sodium and water resorption appeared to be enhanced in the Goldblatt hypertensive rats when compared with the normotensive rats. The renal functional responses to somatic afferent nerve stimulation appeared to be well preserved in the renovascular hypertensive rats, although there were important differences in the contributions to the responses from the left and right kidneys. Furthermore, the baroreceptors exerted a greater influence on basal renal function in the hypertensive rats.

A randomized, double-blind, comparative trial comparing high- and standard-dose oral acyclovir for first-episode genital herpes infections

Orally administered acyclovir ameliorates the clinical course and decreases the duration of viral shedding in patients with first-episode genital herpes infections. We investigated in a randomized, double-blind, comparative trial whether a higher (4 g) than standard (1 g) daily dose of oral acyclovir results in greater clinical benefit and influences the time to first recurrence. A total of 139 patients with first-episode genital herpes were randomized to receive orally 4 or 1 g of acyclovir daily. A total of 52 subjects were excluded from the efficacy analysis because most had recurrent disease. Of 87 eligible subjects, 28 (32%) had primary herpes simplex virus type 1 (HSV-1) infections, 48 (55%) had primary HSV-2 infections, and 11 (13%) had nonprimary HSV-2 infections. We did not find any statistically significant differences in the duration of symptoms or viral shedding between the two dose groups, nor did the median time to first recurrence differ between the two groups. Initiation of therapy with either dose within the first 3 days of the appearance of symptoms shortened the duration of the first episode. Adverse gastrointestinal effects developed in 8% of subjects receiving the higher dose, whereas no adverse reactions were observed among those receiving the standard dose (P = 0.10). We conclude that, in comparison with standard therapy, higher-dose oral acyclovir does not result in additional clinical benefit or modify the time to first recurrence. The present study may have implications for the development and efficacy of congeners of acyclovir which provide higher levels in blood than the standard dose of acyclovir.

Impact of culturally sensitive AIDS video education on the AIDS risk knowledge of African-American adolescents

AIDS video education is a major mode of providing information about the spread and prevention of the human immunodeficiency virus (HIV). Very little has been written about the need for culturally salient messages in increasing the acquisition and retention of HIV/AIDS prevention information, even though there is considerable agreement that limited culturally sensitive information is reaching African-American youth. This investigation sought to ascertain the impact of a culturally similar AIDS video on the acquisition of AIDS knowledge and endorsement of HIV/AIDS prevention beliefs. This study randomly assigned classes of African-American teenagers to one of two treatment groups: culturally similar video (CSV) AIDS education and culturally dissimilar video (CDV) AIDS education. Results suggest that the CSV group demonstrated significant improvement in pre- to post- AIDS knowledge scores compared to the CDV group (using ANCOVA procedures). The intervention was not significant in demonstrating change in beliefs about prevention. Implications for the development of HIV/AIDS prevention programs for inner-city African-American youth are discussed.