Beta 1- and beta 2-adrenergic-receptor subpopulations in nonfailing and failing human ventricular myocardium: coupling of both receptor subtypes to muscle contraction and selective beta 1-receptor down-regulation in heart failure

We used radioligand binding techniques and measurement of beta-agonist-mediated positive inotropic responses in isolated cardiac tissue to examine beta-adrenergic-receptor subpopulations in nonfailing and failing human left and right ventricular myocardium. In tissue derived from 48 human hearts the receptor subtypes identified in nonfailing ventricle by radioligand binding were beta 1 (77%) and beta 2 (23%), with no evidence of an "atypical" beta-adrenergic receptor. In failing left ventricle the beta 1:beta 2 ratio was markedly different, i.e., 60:38. This decrease in the beta 1 proportion and increase in the beta 2 proportion in the failing ventricles were due to a 62%, "selective" down-regulation of the beta 1 subpopulation, with little or no change in beta 2 receptors. In muscle bath experiments in isolated trabeculae derived from nonfailing and failing right ventricles, both beta 1- and beta 2-adrenergic receptors were coupled to a positive inotropic response. In nonfailing myocardium, beta 1 responses predominated, as the selective beta 1 agonist denopamine produced a response that was 66% of the total contractile response of isoproterenol. In heart failure the beta 1 component was markedly decreased, while the beta 2 component was not significantly diminished. Moreover, in heart failure the beta 2 component increased in prominence, as the contractile response to the selective beta 2 agonist zinterol increased from a minority (39%) to a majority (60%) of the total response generated by isoproterenol. We conclude that failing human ventricular myocardium contains a relatively high proportion of beta 2 receptors, due to selective down-regulation of beta 1 receptors. As a result, in the failing human heart the beta 2-receptor subpopulation is a relatively important mediator of inotropic support in response to nonselective beta-agonist stimulation and is available for inotropic stimulation by selective beta 2 agonists.

The mode of delivery and the risk of vertical transmission of human immunodeficiency virus type 1--a meta-analysis of 15 prospective cohort studies

BACKGROUND

To evaluate the relation between elective cesarean section and vertical transmission of human immunodeficiency virus type 1 (HIV-1), we performed a meta-analysis using data on individual patients from 15 prospective cohort studies.

METHODS

North American and European studies of at least 100 mother-child pairs were included in the meta-analysis. Uniform definitions of modes of delivery were used. Elective cesarean sections were defined as those performed before onset of labor and rupture of membranes. Multivariate logistic-regression analysis was used to adjust for other factors known to be associated with vertical transmission.

RESULTS

The primary analysis included data on 8533 mother-child pairs. After adjustment for receipt of antiretroviral therapy, maternal stage of disease, and infant birth weight, the likelihood of vertical transmission of HIV-1 was decreased by approximately 50 percent with elective cesarean section, as compared with other modes of delivery (adjusted odds ratio, 0.43; 95 percent confidence interval, 0.33 to 0.56). The results were similar when the study population was limited to those with rupture of membranes shortly before delivery. The likelihood of transmission was reduced by approximately 87 percent with both elective cesarean section and receipt of antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, as compared with other modes of delivery and the absence of therapy (adjusted odds ratio, 0.13; 95 percent confidence interval, 0.09 to 0.19). Among mother-child pairs receiving antiretroviral therapy during the prenatal, intrapartum, and neonatal periods, rates of vertical transmission were 2.0 percent among the 196 mothers who underwent elective cesarean section and 7.3 percent among the 1255 mothers with other modes of delivery.

CONCLUSIONS

The results of this meta-analysis suggest that elective cesarean section reduces the risk of transmission of HIV-1 from mother to child independently of the effects of treatment with zidovudine.

Natural history of chronic hepatitis B virus infection in Taiwan: studies of hepatitis B virus DNA in serum

Hepatitis B virus DNA (HBV DNA) in serum was measured by a Spot hybridization technique in a consecutive series of 79 cases with chronic HBV infection from Taiwan. HBV DNA was found in 96.3% (52/54) of HBeAg-positive, 66% (2/3) with neither HBeAg or anti-HBe and in 63.6% (14/22) of anti-HBe positive patients. The levels of HBV DNA in the HBe-Ag-positive patients were significantly higher than in the anti-HBe positive patients (median, 944 vs. 58 pg per ml, p less than 0.001). The mean ages increased from 28.7 years for the cases with high levels of HBV DNA, to 34.7 years for those with low levels (p less than 0.01) and to 41.0 years in those without HBV DNA in serum (p less than 0.05 when compared with those with low level of HBV DNA). Ninety per cent of patients (27/30) with high levels of HBV DNA showed only minor hepatic inflammatory activity, as did 91% (10/11) of those without HBV DNA. In contrast, histologic signs of chronic active hepatitis or chronic lobular hepatitis were demonstrated in 76% of cases (29/38) with low levels of HBV DNA. These data are consistent with the hypothesis that liver damage occurs during the period of clearance of hepatocytes supporting HBV replication, and are inconsistent with the view that HBV may be directly cytopathic. Thus, the natural history of chronic HBV infection may be divided into three phases.(ABSTRACT TRUNCATED AT 250 WORDS)

Lack of long-term effects of in utero exposure to zidovudine among uninfected children born to HIV-infected women. Pediatric AIDS Clinical Trials Group Protocol 219/076 Teams

CONTEXT

With the success of zidovudine chemoprophylaxis for prevention of perinatal transmission of the human immunodeficiency virus (HIV), an increasing number of HIV-exposed but uninfected children will have in utero exposure to zidovudine and other antiretroviral drugs.

OBJECTIVE

To evaluate the long-term effects of in utero exposure to zidovudine vs placebo among a randomized cohort of uninfected children.

DESIGN

Prospective cohort study based on data collected during Pediatric AIDS Clinical Trials Group Protocol 076, a perinatal zidovudine HIV prevention trial, and Protocol 219, a long-term observational protocol.

SETTING

Pediatric research clinics in the United States.

PATIENTS

Two hundred thirty-four uninfected children born to 230 HIV-infected women enrolled in Protocol 076 and followed up through February 28, 1997, in Protocol 219 (122 in the zidovudine group and 112 in the placebo group).

MAIN OUTCOME MEASURES

Physical growth measurements, immunologic parameters, cognitive/developmental function, occurrence of neoplasms, and mortality data assessed every 6 months for children younger than 24 months and yearly thereafter or as clinically indicated. Baseline echocardiogram and funduscopic evaluations were collected before 36 months of age.

RESULTS

Median age of children at time of last follow-up visit was 4.2 years (range, 3.2-5.6 years). There were no significant differences between children exposed to zidovudine and those who received placebo in terms of sequential data on lymphocyte subsets; weight, height, and head circumference z scores; and cognitive/developmental function. No deaths or malignancies occurred. Two children (both exposed to zidovudine) are being followed up for abnormal, unexplained ophthalmic findings. One child exposed to zidovudine had a mild cardiomyopathy on echocardiogram at the age of 48 months; the child is clinically asymptomatic.

CONCLUSIONS

No adverse effects were observed in HIV-uninfected children with in utero and neonatal exposure to zidovudine followed up for as long as 5.6 years. Continued prospective evaluations of children born to HIV-infected women who are exposed to antiretroviral or immunotherapeutic agents are critical to assess the long-term safety of interventions that prevent perinatal HIV transmission.

Acute pyogenic meningitis probably due to Acanthamoeba sp.: a preliminary report

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Effect of high- versus low-dose angiotensin converting enzyme inhibition on cytokine levels in chronic heart failure

OBJECTIVES

We examined the effect of long-term treatment with two doses of the angiotensin converting enzyme (ACE) inhibitor enalapril on various immunological variables in patients with chronic congestive heart failure (CHF).

BACKGROUND

Immunological mediators are increasingly recognized to play a pathogenic role in the pathophysiology of CHF. Whether ACE inhibitor therapy modifies immunological variables has not previously been investigated.

METHODS

Seventy-five patients (mean age 52 +/- 11 years) with CHF were randomized between low-(5 m g daily) and high-dose (40 mg daily) enalapril in a double-blind trial. Circulating levels of immunological parameters (i.e., proinflammatory cytokines, chemokines and adhesion molecules) were measured at baseline, at 10 weeks and at the end of the study (34 weeks).

RESULTS

All immunological parameters, except soluble interleukin (IL)-6 receptor, were increased in CHF compared with 21 healthy controls. During the study immunoreactive IL-6 levels decreased (p < 0.05) and soluble IL-6 receptor increased (p < 0.05) during high-dose but not during low-dose enalapril therapy. Furthermore, IL-6 bioactivity decreased only during the high-dose (p < 0.001), resulting in a significant difference in change during treatment between the two dosage groups (p < 0.001). This decrease in IL-6 bioactivity was significantly associated with decreased interventricular septum thickness as assessed by echocardiography (r = 0.56, p = 0.013). No other variables changed during treatment.

CONCLUSIONS

In patients with severe CHF, high-dose enalapril therapy is associated with a significant decrease in IL-6 activity. However, despite treatment with a high-dose ACE inhibitor, a persistent immune activation exists in these patients which may be of importance for the progression of CHF.

The detection of HBV-DNA in serum by molecular hybridisation: a more sensitive method for the detection of complete HBV particles

Existing methods for detecting complete virus particles in the serum of patients with chronic HBV infection are either insensitive or indirect. A method is described in which Dane particle-associated DNA is extracted from a small volume of serum and detected by molecular hybridization using 32P-labeled cloned HBV-DNA or HBV-DNA extracted from the serum of an immunosuppressed patient, followed by autoradiography and densitometry. There was a positive correlation between the amount of HBV-DNA detected using HBV particle-derived and cloned HBV-DNA probes. The amount of HBV-DNA detected in serum samples showed a positive correlation with the HBV-DNA polymerase. The method was more sensitive than the DNA polymerase and HBeAg assays in detecting complete virus particles. It may be useful in determining the level of infectivity in patients and in monitoring response to antiviral therapy.

Sleep and memory

Two experiments demonstrated that memory over an interval with relatively high amounts of rapid eye movement (REM) sleep was inferior to memory over an interval with relatively high amounts of stage 4 sleep. The results suggest that, at least for humans, REM sleep does not facilitate memory consolidation and that stage 4 sleep may be beneficial to memory.

Intrathecal drug delivery in the era of nanomedicine

Administration of substances directly into the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord is one approach that can circumvent the blood-brain barrier to enable drug delivery to the central nervous system (CNS). However, molecules that have been administered by intrathecal injection, which includes intraventricular, intracisternal, or lumbar locations, encounter new barriers within the subarachnoid space. These barriers include relatively high rates of turnover as CSF clears and potentially inadequate delivery to tissue or cellular targets. Nanomedicine could offer a solution. In contrast to the fate of freely administered drugs, nanomedicine systems can navigate the subarachnoid space to sustain delivery of therapeutic molecules, genes, and imaging agents within the CNS. Some evidence suggests that certain nanomedicine agents can reach the parenchyma following intrathecal administration. Here, we will address the preclinical and clinical use of intrathecal nanomedicine, including nanoparticles, microparticles, dendrimers, micelles, liposomes, polyplexes, and other colloidalal materials that function to alter the distribution of molecules in tissue. Our review forms a foundational understanding of drug delivery to the CSF that can be built upon to better engineer nanomedicine for intrathecal treatment of disease.

Detection of serum HBV-DNA by molecular hybridisation. Correlation with HBeAg/anti-HBe status, racial origin, liver histology and hepatocellular carcinoma

The relationship of the presence of hepatitis B virus (HBV) DNA in serum, a measure of HBV-replication, to HBeAg/anti-HBe status has been examined. In Northern Europe, there is a strong positive correlation between the presence of HBV-DNA and HBe antigenaemia and a negative correlation with the presence of anti-HBe. These associations are less marked in patients from Southern Europe, Africa, the Middle and Far East. When HBV-DNA is present in the serum of anti-HBe carriers, it is usually associated with the presence of severe liver disease or carcinoma. Forty percent of patients with hepatocellular carcinoma had evidence of continuing HBV replication.

Thrice weekly lymphoblastoid interferon is effective in inhibiting hepatitis B virus replication

Six patients with chronic hepatitis B virus (HBV)-induced liver disease were treated with human lymphoblastoid interferon. Daily, alternate day or thrice weekly regimens were employed in two, one and three patients respectively. Thrice weekly intra-muscular injections of 7.5 to 10 megaunits of interferon/m2 appeared to be as effective as daily injections in producing inhibition of HBV replication, were associated with fewer side effects and could be continued for up to 3 months. The effectiveness of this regimen in producing long-term inhibition of viral replication must now be determined.

Successful treatment of HBs and HBeAg positive chronic liver disease: prolonged inhibition of viral replication by highly soluble adenine arabinoside 5'-monophosphate (ARA-AMP)

In eight HBs and HBe antigen positive patients with chronic active liver disease, adenine arabinoside 5'-monophosphate (ARA-AMP) given, intravenously or intramuscularly, six or 12 hours, produced inhibition of viral replication. In five patients given a short course of therapy with 10 or 15 mg/kg/day this effect was transient and in two thrombocytopenia occurred. In three further consecutive cases given a longer course with 5 mg/kg/day after five days of the high dose, thrombocytopenia was not seen and inhibition of viral replication for up to 13 months occurred. These patients lost HBV-DNA polymerase activity, serum viral DNA and HBeAg, developed anti-HBe, and HBsAg concentrations decreased. A course of twice daily intramuscular ARA-AMP given for three to five weeks as an outpatient may be expected to produce a long-term reduction in infectivity.

Effects of transitory cognitive impairment on psychosocial functioning of children with epilepsy: a therapeutic trial

The authors report a trial of the use of anti-epileptic medication to treat possible cognitive deficits due to subclinical epileptiform EEG discharges in 10 children with psychosocial and educational problems associated with epilepsy. Medication intended to suppress the EEG discharges was added to the children's existing drug regime. In all instances, epileptiform activity, assessed by 24-hour periods of ambulatory monitoring, was reduced on active medication compared with placebo. In general, there was improvement of psychosocial function on active treatment: eight children improved, there was no change in one and one deteriorated. No psychosocial deterioration attributable to adverse effects of the medication was detected in those completing the trial. Despite possible confounding factors, the findings are in accordance with the view that subclinical EEG discharges can impair psychosocial function, which may be ameliorated by anti-epileptic medication.

Hepatitis B virus DNA in saliva, urine, and seminal fluid of carriers of hepatitis B e antigen

Concentrated samples of saliva, urine, and seminal fluid from 23 men with chronic liver disease who were positive for hepatitis B e antigen were examined for the presence of hepatitis B virus deoxyribonucleic acid (HBV-DNA) by molecular hybridisation. HBV-DNA was detected in saliva from 15 of 17 men (88%), urine from 12 of 22 men (55%), and seminal fluid from 13 of 21 men (62%). The presence of hepatitis B virus in such secretions has important epidemiological implications for heterosexual and homosexual contact.

The Pena-Shokeir syndrome: report of five cases and further delineation of the syndrome

We report on five cases of lethal Pena-Shokeir syndrome from three families with affected sibs. In addition to multiple anklyoses, camptodactyly, facial anomalies, and pulmonary hypoplasia, one fetus had pterygia of the neck and axillae and cardiac hypoplasia. Radiographic changes are nonspecific and probably are related to a lack of intrauterine movement. Our data and review of the literature suggest that pterygium formation is one of the manifestations of the Pena-Shokeir syndrome. A recently described lethal form of the recessively inherited multiple pterygium syndrome may represent a severe form of the Pena-Shokeir syndrome.

Short rib-polydactyly syndrome, Majewski type

A term infant had dwarfism with characteristic skeletal and extraskeletal changes of the short rib-polydactyly syndrome type 2 (Majewski). The skeletal changes included extremely short horizontal ribs, extreme micromelia with disproportionately short ovoid tibiae, and pre- and post-axial polydactyly. Microscopically, cartilage showed markedly stunted and disorganized endochondral ossification. Extraskeletal manifestations were hydrops, cleft lip, malformed larynx with hypoplastic epiglottis, pulmonary hypoplasia, glomerular and renal tubular cysts, ambiguous genitalia, pachygyria and small cerebellar vermis. Parental consanguinity supports the hypothesis of autosomal recessive inheritance of the condition.

Tricresyl phosphate inhibits the formation of axon-like processes and disrupts neurofilaments in cultured mouse N2a and rat PC12 cells

Tricresyl phosphate (1 microg/ml) inhibited the outgrowth of axon-like processes in mouse N2a neuroblastoma and rat PC12 pheochromocytoma cell lines induced to differentiate by serum withdrawal and nerve growth factor addition, respectively. By contrast, it had no effect on the outgrowth of processes by rat C6 glioma cells induced to differentiate with sodium butyrate. The effect on axon outgrowth in the two neuronal cell lines correlated with altered distribution of neurofilament proteins, as determined by indirect immunofluorescence with monoclonal antibody RMd09. Western blots of neuronal cell extracts probed with the same antibody revealed decreased cross-reactivity after exposure to tricresyl phosphate. The results suggest that tricresyl phosphate has a selective effect on neuronal cell differentiation, which involves impaired axon outgrowth, reduced levels of the neurofilament heavy chain and disruption of the neurofilament network.

Integration of HBV-DNA may not be a prerequisite for the maintenance of the state of malignant transformation. An analysis of 110 liver biopsies

Hundred and ten liver biopsy specimens from various parts of the world were examined for episomal and integrated HBV-DNA sequences. In 54 patients with HBsAg chronic liver disease episomal HBV-DNA was found in 83% of HBeAg-positive patients, compared to only 22% of patients with anti-HBe. Furthermore episomal HBV-DNA in the latter predominated among the Asians. Integrated HBV-DNA was found only in 5.5% of HBeAg-positive patients but in 16.5% of patients with anti-HBe. In 28 HBsAg-positive patients with hepatoma, episomal HBV-DNA was found in 50% of HBeAg-positive patients but in only 11% of anti-HBe patients. Conversely integrated sequences were less common (25%) in HBe-Ag-positive patients than in anti-HBe patients (50%), giving an overall incidence of integration in this group of 45%. No episomal, and only one case of integrated sequences of HBV-DNA, could be detected among 10 patients with HBsAg-negative hepatoma. In addition neither episomal nor integrated HBV-DNA could be detected in 18 patients with non-HBV-related liver disease. Our data suggests that stable integration of HBV-DNA into the host's genome is not necessarily a prerequisite for the maintenance of the state of malignant transformation but may be necessary for its initiation. Alternatively, the detection of integrated HBV-DNA may represent a 'snap shot' of a random integration event amplified by clonal expansion promoted by other factors.

Acyclovir in hepatitis B antigen-positive chronic liver disease: inhibition of viral replication and transient renal impairment with iv bolus administration

Six patients with hepatitis B virus (HBV) related chronic liver disease were treated with acyclovir, 5-15 mg/kg 8 hourly, given as an iv bolus or iv infusion over 1 h for up to 7 days. Two patients treated with 10 and 15 mg/kg 8 hourly showed a decrease in HBV-DNA polymerase and HBV-DNA when mean trough acyclovir plasma concentrations of 5.0 +/- 0.6 and 13.2 +/- 3.0 microM were attained. Inhibition of viral replication was not seen in patients treated with lower doses. Transient renal impairment was seen in two patients who received high dosage by the iv bolus mode of administration. This complication may be prevented by a high oral fluid intake or iv infusion of the drug over 1 h. Further study with acyclovir 15 mg/kg 8-hourly given as an iv infusion for longer periods is warranted.

Tracheoesophageal fistula formation in intubated patients. Risk factors and treatment with high-frequency jet ventilation

Two ventilator dependent patients developed tracheoesophageal fistulas. Their subsequent treatment using high frequency jet ventilation resulted in transient clinical improvement. Risk factors for the development of tracheoesophageal fistulas in intubated patients are discussed and preventive measures are outlined. High frequency jet ventilation may be useful in managing these patients by preventing death from respiratory failure and allows time for definitive therapy.