HEPES inhibits contractile responses of canine basilar artery

N-2-hydroxyethylpiperazine-N'-2-ethanesulphonic acid (HEPES) is a commonly-used buffer. This study determined the effect of HEPES on contractility of the dog basilar artery and tested the hypothesis that HEPES inhibits vasoconstriction of isolated arterial segments by generating H2O2. Rings of dog basilar artery with or without endothelium were suspended under isometric tension and contracted with KCl, serotonin, or prostaglandin F2 alpha (PGF2 alpha) in bicarbonate or HEPES buffer. Addition of HEPES, 30 mmol l-1, before or after contraction with KCl, serotonin or PGF2 alpha significantly decreased maximal tension in rings with or without endothelium. Preincubation with HEPES buffer, 10 mmol l-1, significantly decreased maximal contractions to each agonist in rings with endothelium and to KCl and serotonin in rings without endothelium. HEPES, 30 mmol l-1, noncompetitively inhibited concentration-contraction curves to increasing concentrations of each agonist in rings with or without endothelium. Inhibition by HEPES was completely reversible with washing. The inhibitory effects of HEPES on responses to each agonist in rings with endothelium were significantly less in the dark or after coincubation with catalase. Unlike HEPES, effects of H2O2 were endothelium-dependent in that H2O2 caused contractions in rings with endothelium and relaxations in rings without endothelium. 5-(N,N'-dimethyl)-amiloride and 4,4'-diisothiocyanataostilbene-2,2'-disulfonic acid did not affect contractility in this preparation. These results show that HEPES exerts significant inhibitory effects on arterial smooth muscle contractility. The mechanism does not involve endothelium-dependent relaxation, effects on chloride channels or the sodium-hydrogen exchanger or generation of H2O2 by HEPES in the light.

Infant age, context, and family system influences on the interactive behavior of mothers of infants with mental delay

Interactive behavior of 30 mothers of infants with mental delay and 30 comparison mothers and infants was examined in relation to child age (first and second year), context (feeding versus teaching), maternal characteristics (family stress, coping resources), and family social system (maternal education). Groups were compared from two perspectives: with infants matched on mental age (9 and 19 months MA), and on chronological age (8 and 18 months CA). Study mothers scored lower than comparison mothers during teaching but not during feeding in year 1 with both MA and CA match, but only with the CA match in year 2. Study infants scored lower than comparison infants in both contexts in year 1, but not in year 2. Groups did not differ on maternal or family measures. In year 1, group status, coping, and maternal education were predictive of mother interaction. In year 2, only maternal education was predictive. Results confirm the importance of type of match, context, and family system variables in understanding effects of child mental delay on maternal interactive behavior.

Phase II study of topotecan in patients with advanced non-small-cell lung cancer previously untreated with chemotherapy

PURPOSE

This study was designed to assess the anti-tumor activity of topotecan (TPT) in patients with advanced non-small-cell lung cancer (NSCLC) previously untreated with chemotherapy.

PATIENTS AND METHODS

Patients with stage IIIB or IV NSCLC with measurable disease in nonradiated fields were eligible. Other eligibility criteria were Zubrod performance status (PS) < or = 2 and adequate renal and liver function. TPT was administered at a dose of 1.5 mg/m2/d for 5 days over 30 minutes every 21 days. Of 48 registered patients, 40 were fully assessable. Nineteen patients had adenocarcinoma (AD), 14 squamous carcinoma (SCC), and seven poorly differentiated carcinoma.

RESULTS

Six patients (15%) achieved a partial remission (PR) (durations: 8, 14, 18, 28, 56, and 61 weeks) and four patients a minor response; 10 patients had stable disease and 20 patients progressive disease. The PR rate was 36% (five of 14 patients) in patients with SCC versus 4% (one of 26 patients) in those with other histologies (P = .014). The overall median survival time was 38 weeks and 30% of patients were alive at 1 year. Grade 3 to 4 granulocytopenia and thrombocytopenia occurred after 76% and 10% of courses administered, respectively. No grade 3 to 4 nonhematologic toxicities were observed. Grade 1 or 2 nonhematologic toxicities consisted of nausea (46% and 5%), vomiting (31% and 7%), and fatigue (53% and 16%).

CONCLUSION

TPT at the dose and schedule used has moderate antitumor activity in NSCLC; its activity is mostly limited to patients with SCC. TPT is well tolerated, with myelosuppression of short duration being the most common and limiting toxicity.

Analysis of the dual discrimination ability of the two-port photorefractive joint transform correlator

An all-optical joint transform correlator featuring two operative correlation planes(ports) with complementary performance is presented. We present the theory of operation, derive the input-output characteristics, and demonstrate computer simulations and experimental results. The two-port joint transform correlator is based on simultaneous use of two photorefractive wave-mixing architectures. The first port uses two-beam coupling, and the second port uses four-wave mixing. The performance of the two ports depends on an experimentally controlled beam intensity ratio and the photorefractive coupling coefficient. With appropriate selection of these parameters, the first port is capable of high discrimination, while simultaneously the second offers a low discrimination output. Our results show that the two-beam coupling port can achieve peak-to-noise and signal-to-noise ratio values better than the phase-only correlator, whereas the four-wave-mixing port performs similarly to the classical joint transform correlator. This leads to a potential application in which the correlator could be set up so that in one port a general class is detected (interclass) and, in the other, the specific item in a class is detected (intraclass).

Adenosine-induced coronary vasodilation during transesophageal Doppler echocardiography. Rapid and safe measurement of coronary flow reserve ratio can predict significant left anterior descending coronary stenosis

BACKGROUND

Less invasive methods are replacing traditional invasive means of measuring coronary flow reserve (CFR). Transesophageal echocardiography (TEE) is becoming a useful tool for evaluation of coronary artery disease and has recently been used to measure CFR. This has always been done using dipyridamole, but adenosine has a greater vasodilator potency and more favorable kinetics than dipyridamole. This study was done to evaluate the hypothesis that adenosine is safe, rapid, and accurate in measuring coronary blood flow reserve by TEE Doppler.

METHODS AND RESULTS

Forty-nine patients who had recently undergone angiography had a transesophageal echocardiogram with visualization of the coronary arteries and measurement of blood flow velocity in the left anterior descending coronary artery (LAD) during adenosine infusion of 0.14 mg/kg per minute. Angiograms were analyzed by quantitative coronary angiography, and significant stenosis was defined as > 70% lumenal diameter narrowing. Thirty-nine of the 49 patients did not have a significant LAD stenosis (group 1); the remainder had significant disease (group 2). Good spectral Doppler recordings of blood flow velocity in the LAD were obtained in 41 of 46 patients (89%). There were no significant differences in baseline coronary blood flow velocities between the two groups. Hyperemic to baseline flow ratios were significantly higher in patients without significant LAD stenosis for peak (2.83 +/- 1.04 versus 1.78 +/- 0.36) and mean (2.68 +/- 0.96 versus 1.75 +/- 0.39) diastolic velocity. A CFR ratio > 2.1 had a sensitivity of 86%, a specificity of 79%, a positive predictive value of 46%, and a negative predictive value of 96% for the absence of critical LAD stenosis. The infusion was well tolerated. It had to be prematurely terminated in only 3 patients (6.5%), and they were asymptomatic. No patient experienced chest pain, palpitations, or flushing. Intraobserver and interobserver variabilities were low, and reproducibility of data was good (< 4%).

CONCLUSIONS

Adenosine Doppler TEE is an effective, rapid, safe, and superior means of measuring CFR ratio. This method is convenient for serial measurements of CFR as well as in clinical settings such as evaluation of syndrome X, cardiomyopathy, and aortic regurgitation.

Predictors for altering caffeine consumption during stress

The present study investigated whether or not those who self-report increasing use of caffeine when under stress consume caffeine more for the drug (e.g., stimulant) effects. A three-part questionnaire assessing demographic information, caffeine use patterns, and reasons for use was completed by 182 females and 106 males (mean age, 22.4 years; range, 9 to 59). Consistent with earlier research, nearly 50% of the sample reported increasing consumption of coffee or soft drinks when under stress. Hierarchical multiple regression analyses showed drinking for relief reasons as the most consistent predictor for altering caffeine use when under stress. Understanding differences in use patterns will likely help strengthen the ability to describe the extent to which caffeine use contributes to cardiovascular and other disorders.

Gender differences in onset of illness, treatment response, course, and biologic indexes in first-episode schizophrenic patients

OBJECTIVE

Gender differences in onset of illness, response to treatment, course, and biologic measures have been consistently reported in patients with chronic schizophrenia. Patients with first-episode schizophrenia were examined to determine whether gender differences also occur in these patients.

METHOD

Fifty-four neuroleptic-naive schizophrenic patients (29 men and 25 women) were studied beginning in an initial stage of the first hospitalization for psychosis while undergoing treatment with a standardized medication regimen. Before antipsychotic drug treatment and during 1 year of follow-up each patient was rated on the Schedule for Affective Disorders and Schizophrenia--Change Version (psychosis and disorganization items), Scale for the Assessment of Negative Symptoms, Clinical Global Impression, modified Simpson Tardive Dyskinesia Scale, and Simpson-Angus Rating Scale for extrapyramidal side effects. Methylphenidate challenge testing was done at study entry. Plasma neuroleptic, homovanillic acid (HVA), and prolactin levels were determined weekly for the first 6 weeks.

RESULTS

The female schizophrenic patients had a later onset and better treatment response than the men. Plasma HVA levels at baseline and week 1 and changes in prolactin levels from baseline to weeks 1 through 6 were greater among the women.

CONCLUSIONS

Gender differences in onset and degree of treatment response in first-episode schizophrenic patients are similar to those of chronic patients and are apparent at early stages of the illness. The greater pharmacologic responsivity of the female patients, as indicated by the neuroendocrine results, is consistent with the gender difference in degree of symptom improvement with medication.

Rural Minnesota family physicians' attitudes toward telemedicine

This study reports the results of an assessment of the attitudes and opinions of rural Minnesota family physicians toward telemedicine. The results of 52 mail surveys and 32 telephone interviews were compiled to determine existing attitudes and levels of awareness concerning aspects of telemedicine. Surveyed physicians overwhelmingly agreed that they do not have sufficient information about telemedicine. Their awareness of telemedicine's applications and capabilities is minimal. Also, responding physicians indicated little knowledge regarding such important issues as cost-effectiveness, reimbursement, liability, and potential primary care benefits. In general, however, physicians' attitudes toward telemedicine were favorable. This information should be important to funders, suppliers, and potential users of telemedicine. This study suggests a need to educate medical students, residents, and practicing physicians about telemedicine and issues related to its use.

Application of the API YeastIdent system in determining the enzymatic profiles of Nocardia asteroides isolates

Glucose represses production of ammonium in many clinical isolates of Nocardia asteroides growing on bromcresolpurple casein glucose agar. Strains exhibiting this property are designated as group A, while group B represents isolates showing a high degree of proteolytic activity and a resulting rapid increase in pH. Twenty isolates of N. asteroides were characterized as group A or B. Enzymatic profiles obtained using the API YeastIdent system showed significant enzymatic variation between 12 group B and 8 group A isolates. Proteolytic enzymes which most varied in activity between groups were glycine aminopeptidase, histidine aminopeptidase and leucyl glycine aminopeptidase. As some of the N. asteroides isolates were isolated from asymptomatic patients, it is of interest to consider the possibility of one group being of low virulence while the other is more strongly associated with infection.

A prospective study of the prevalence of clear-cut endocrine disorders and polycystic ovaries in 350 patients presenting with hirsutism or androgenic alopecia

OBJECTIVE

To determine the frequency of polycystic ovaries (PCO) on ultrasound and the incidence of clearcut endocrine disorders leading to virilization in patients complaining of hirsutism or androgenic alopecia. The major purpose was to determine a coherent policy for the routine biochemical assessment of such women.

DESIGN

A prospective study of women attending a joint skin/endocrine clinic complaining of these problems.

PATIENTS

Three hundred and fifty consecutive women with hirsutism and/or androgenic alopecia were assessed.

MEASUREMENTS

Baseline endocrine screens were conducted on two occasions and included measurement of serum testosterone, androstenedione, dehydroepiandrosterone sulphate, sex hormone binding globulin, LH, FSH, 17-hydroxyprogesterone and PRL. The ovaries were visualized by high-resolution pelvic ultrasound scanning.

RESULTS

Eight women were identified with relevant endocrine disorders; of these, one was acromegalic and one had a microprolactinoma--in both cases the association may have been fortuitous. Three had clear-cut 21-hydroxylase deficiency, one a rare hepatic enzyme deficiency (11-reductase), one a virilizing adrenal carcinoma and one a Leydig cell tumour. The latter six cases all had persistently elevated levels of serum testosterone (> 5 nmol/l). In all, 13 women had baseline testosterone levels in excess of 5 nmol/l. Polycystic ovaries were present in 81% of the cases who had erratic cycles and 52% of those with regular cycles; PCO were present in two of the women with 21-hydroxylase deficiency and in the woman with 11-oxoreductase deficiency. The Leydig cell tumour (1.2 cm diameter) was not detected on ultrasound or CT scan.

CONCLUSIONS

For the exclusion of enzyme deficiencies and virilizing tumours clinical assessment and a single serum testosterone measurement will suffice.

Neural modulation of muscle contractile properties during fatigue: afferent feedback dependence

H reflex amplitudes, an indirect measure of the excitability of the alpha motoneuron pool, were recorded from 10 males during fatigue induced by submaximal, isotonic, voluntary contractions of the soleus muscle. H reflex changes were correlated with electromyographic changes (mean power frequency (MPF); root mean square (rms EMG)), under ischemic and non-ischemic conditions. The purpose of the ischemia was to block transmission of Ia and possibly Ib afferents to assess whether changes in sensory feedback had any effect on alpha motoneuron and EMG activity during fatigue. Significant interactions were found between ischemic and non-ischemic conditions. After an initial decrease (1.21 +/- 0.56 mV to 0.54 +/- 0.39 mV), H reflex amplitudes increased during non-ischemic trials (0.54 +/- 0.39 mV to 1.13 +/- 0.84 mV). Under ischemic conditions H reflex amplitudes decreased (2.11 +/- 1.10 mV to 0.70 +/- 0.74 mV; P < 0.003). During non-ischemic conditions, MPF decreased across 5 consecutive trials (157.7 +/- 17.9 Hz to 124.7 +/- 17.2 Hz), as compared to an increase under ischemic conditions (132.8 +/- 21.2 Hz to 197.1 +/- 53.6 Hz; P < 0.001). Root mean square amplitude decreased during the non-ischemic trials (31.07 +/- 14.62 mV to 25.98 +/- 8.26 mV). A greater decrease was noted during the ischemic trials (34.00 +/- 23.61 mV to 4.95 +/- 3.77 mV; P < 0.001). Data suggest that the CNS modulates muscle contraction in order to preserve force output and neuromuscular transmission during fatigue. This modulation appears dependent on Ia and/or Ib afferent feedback.

Relation of plasma fluphenazine levels to treatment response and extrapyramidal side effects in first-episode schizophrenic patients

OBJECTIVE

The aim of this study was to determine the relation between plasma fluphenazine levels and clinical response in first-episode schizophrenic patients.

METHOD

Data from 36 first-episode schizophrenic or schizoaffective inpatients diagnosed according to the Research Diagnostic Criteria were evaluated. The patients received open, standardized treatment with fluphenazine, 20 mg/day, for at least 4 weeks. Psychopathology was assessed biweekly, and plasma fluphenazine levels were ascertained weekly. Patients were classified as responders or nonresponders, and correlations between their neuroleptic levels and ratings of psychopathologic and extrapyramidal symptoms were computed.

RESULTS

Plasma fluphenazine levels for weeks 1 through 4 were significantly correlated with each other but were not correlated with age, gender, diagnosis, or race. Mean neuroleptic levels (weeks 3 and 4) were not different between responders and nonresponders and were not correlated with measures of psychopathology or extrapyramidal symptoms.

CONCLUSIONS

These results do not indicate an association between plasma fluphenazine levels and response to treatment or extrapyramidal side effects in first-episode schizophrenia. The disparity between the results of this study and those of previous studies may be due to methodological differences or to a biologically based difference between first-episode and chronic patients.

Early results with cryopreserved saphenous vein allografts for infrainguinal bypass

PURPOSE

Cryopreserved saphenous vein allografts (CSVA) are available for use in arterial reconstructions; however, patency rates in the infrainguinal position are not well described.

METHODS

We reviewed our experience with 38 patients who underwent 43 infrainguinal bypasses with CSVA as the conduit. The group includes 21 women and 17 men with a mean age of 69 +/- 11 years. Mean follow-up is 8.2 +/- 5.5 months. Logistic regression was used to analyze five variables in an attempt to identify predictors of success or failure: distal anastomosis to the popliteal artery versus a crural artery, one-vessel versus two- or three-vessel runoff, postoperative anticoagulation versus none, primary reconstructions versus reoperations, and one segment versus two segments of CSVA required.

RESULTS

The cumulative patency rate at 12 months by life-table analysis is 66%. Logistic regression revealed that primary reconstructions were more likely to succeed than reoperations (p = 0.03) and operations completed with one segment of CSVA were more likely to succeed than those requiring more than one segment of vein (p = 0.03).

CONCLUSIONS

We conclude that (1) the short-term patency of infrainguinal bypasses with CSVA suggests that they may be acceptable alternatives to prosthetic grafts in the below-knee position, and (2) primary reconstructions performed with one segment of CSVA are more likely to succeed.

Use of lateral heel and sole wedges in the treatment of medial osteoarthritis of the knee

The authors discuss the use of lateral heel wedges in the treatment of medial osteoarthritis of the knee in 121 knees in 85 patients. Follow-up was an average of 12 months after the insertion of the wedge. Patients' roentgenograms were graded according to the Ahlback classification, and various improvements were noted. Overall, 38% of patients improved to a Hospital for Special Surgery pain score of 25 or 30, which corresponds to an excellent result from total knee arthroplasty. Fifty percent of patients improved to a pain score of 20 or higher, which corresponds to a good result from total knee arthroplasty. The patients with milder osteoarthritis received greater pain relief. However, even patients with complete loss of joint space and bony erosion showed some improvement. It appears that the use of lateral wedges has a place in the conservative treatment of medial osteoarthritis.