Dietary protein supplementation and recovery from femoral fracture

A recent randomized, double-blind, placebo-controlled trial found that protein supplementation improved recovery from femoral fractures in an elderly population. A 6-month course of protein supplementation (20 g/day, 5 days/week) improved serum prealbumin and insulin-like growth factor I (IGF-I) concentrations, minimized bone loss, and decreased length of stay in rehabilitation facilities.

Milk consumption in older Americans

OBJECTIVES

The purpose of this study was to identify individual characteristics associated with types and frequency of milk consumption in older American adults.

METHODS

A national probability-based sample (response rate = 91%) completed a telephone survey. Generalized logit and cumulative logit analyses were used to identify predictors of and barriers to fluid milk consumption in 494 elderly people.

RESULTS

The likelihood of drinking skim or 1% milk rather than whole milk increased with nutrition knowledge, income, trying to reduce cholesterol intake, and being female (P < .05). Frequency of milk consumption was higher with nutrition knowledge, frequency of milk consumption during adolescence, and following a diabetic diet but was lower with milk intolerance.

CONCLUSIONS

The present results could be used to develop intervention strategies for improving milk consumption rates among older adults. These strategies might focus on increasing elderly people's awareness of milk intolerance and lactose-reduced milk products and their concern about cholesterol. The relationship between current and adolescent milk consumption suggests that intervention strategies should begin early in life.

Nucleotide sequence of the left-terminus of infectious laryngotracheitis virus (Gallid herpesvirus 1) SA-2 strain

The nucleotide sequence of 10.6 kilobase pairs (kbp) at the leftterminus of infectious laryngotracheitis virus (ILTV) SA-2 vaccine strain was determined. Several features were elucidated, including, 102 base pair (bp) inverted repeats separated by 750 bp of unique sequence which contains an NF-1 binding site indicating that the terminal may be a site for an origin of replication. Other direct repeats were also found in this region. To the right of the inverted repeat region, a 2130 bp region was found to contain small open reading frames (ORFs) of less than 100 aa. Another potential ORF was found to the right of the region containing the small ORFs which consisted of two 184 bp direct repeats inserted into the reading frame, which would truncate the putative product. Only one copy of this repeat was found in the corresponding homologue of the wild type strain SA-0. Six other ORFs were found, which shared little or no identity to homologues of other alphaherpesviruses, suggesting that these putative genes are unique to ILTV.

Research bronchoscopies do not adversely affect HIV-infected individuals' future health-care decisions

STUDY OBJECTIVES

Asymptomatic HIV-infected individuals are increasingly recruited for studies involving invasive procedures such as bronchoscopy. We sought to determine the response to and outcome of a request for a research bronchoscopy in HIV-positive individuals with no respiratory disease, and whether this would adversely affect future decisions to have a medically indicated bronchoscopy.

DESIGN AND SETTING

Prospective, semistructured, questionnaire-based study in a London teaching hospital HIV outpatient clinic.

PARTICIPANTS

One hundred and seven consecutive HIV-infected eligible individuals. Thirty-one healthy volunteers served as a control group for the subjective response to bronchoscopy.

MAIN OUTCOME MEASURES

Subjects' attitudes and responses to requests for bronchoscopy and subsequent behavior when they required medically indicated bronchoscopy.

RESULTS

Seventy-five patients (70%) agreed to the procedure in principle, predominantly for altruistic reasons. Thirty-nine subjects underwent bronchoscopy. Five percent found it worse than expected; and 79% agreed to another research bronchoscopy (performed in 11 subjects approximately 2 years later). All patients said they would undergo bronchoscopy again for diagnostic purposes (required in seven during the study). When compared to a healthy volunteer population within the same study, postbronchoscopy symptoms were similar in frequency although somewhat different in nature. Subjects felt that a clear explanation of what was involved enhanced their participation in this research.

CONCLUSIONS

Invasive research procedures such as bronchoscopy can be performed and are repeatable in a healthy HIV-infected population. Performance of procedures for research purposes does not appear to adversely affect future health-care decisions.

Single dose pharmacokinetics of lamivudine in subjects with impaired renal function and the effect of haemodialysis

AIMS

The purpose of this study was to investigate the pharmacokinetics of a single oral dose of lamivudine administered to subjects with renal impairment and to determine whether lamivudine was dialysable in subjects with severe renal impairment undergoing haemodialysis.

METHODS

Twenty-nine subjects were enrolled, nine with normal renal function (creatinine clearance (CL(CR)) 82-117 ml min(-1)), eight with moderately impaired renal function (CL(CR) 25-49 ml min(-1)), six with severe impairment (CL(CR) 13-19 ml min(-1)) and six with severe impairment who were also receiving haemodialysis. After an overnight fast, nondialysis subjects received a single oral dose of lamivudine. Subjects on haemodialysis were given two doses on separate occasions (intra and interdialysis). Blood was obtained before lamivudine administration and at regular intervals to 48 h post dose. Timed urine collections were performed for subjects able to produce urine. Pharmacokinetic parameters were calculated by using standard non compartmental techniques.

RESULTS

Decreasing renal function was associated with reduced lamivudine clearance in a proportional and apparently linear relationship. Lamivudine was well dialysed with an extraction ratio in the order of 50%. However, because lamivudine has a large volume of distribution (approximately 100 1), a haemodialysis session of 4 h did not affect overall exposure to a clinically significant degree in most subjects.

CONCLUSIONS

Impaired renal function does require lamivudine dose modification according to the degree of impairment, but no further modification of dose is required for subjects undergoing regular haemodialysis.

Epidemiology of cerebral palsy in England and Scotland, 1984-9

AIMS

To report on the epidemiology of cerebral palsy in England and Scotland, to provide information on the prevalence of cerebral palsy and the severity of the disability or any co-morbidity.

METHODS

Cerebral palsy registers were compiled from multiple sources of ascertainment covering all of Scotland and the counties of Merseyside, Cheshire, Berkshire, Buckinghamshire, Northamptonshire and Oxfordshire in England. All cases of cerebral palsy born in 1984 to 1989, to mothers resident in the area, were included. Denominator number of live births and neonatal deaths for determining birthweight specific prevalence were obtained from birth and death registrations. Learning, manual, and ambulatory disabilities were graded for severity. Any co-existing sensory (hearing or visual) morbidity was also graded for severity.

RESULTS

There were 789,411 live births in 1984-9, with 3651 neonatal deaths (neonatal mortality 4.6 per 1000 live births) and 1649 cases of cerebral palsy--a cerebral palsy prevalence of 2.1 per 1000 neonatal survivors. The birthweight specific cerebral palsy prevalence ranged from 1.1 per 1000 neonatal survivors in infants weighting > or = 2500 g to 78.1 in infants weighing < 1000 g. There was no significant time trend in prevalence of cerebral palsy in any of the birthweight groups, in contrast to the fall in neonatal mortality observed in all birthweight groups. Of the 1649 cases of cerebral palsy, 550 (33.4%) had severe ambulatory disability (no independent walking), 390 (23.7%) had severe manual disability (incapable of feeding or dressing unaided), 381 (23.1%) had severe learning disability (IQ < 50), 146 (8.9%) had severe visual disability (vision < 6/60 in the better eye) and 12 had severe hearing disability (> 70 dB loss).

CONCLUSIONS

Registers fill an important gap left by the lack of routine data on the prevalence of disability in children. The ability to record trends in the prevalence and the severity of the disability should inform those who have responsibility for providing services for children with disabilities.

Regional differences in GABA and GAD immunoreactivity in rabbit horizontal cells

Mammalian horizontal cells are believed to be GABAergic because, in most species, they contain both GABA and glutamic acid decarboxylase (GAD), and their terminals are presynaptic to GABA receptors. In adult rabbit, however, GABA and GAD immunoreactivity have not been consistently demonstrated in horizontal cells, casting doubts on the assumption that they too are GABAergic. Here we demonstrate that all rabbit horizontal cell terminals--dendritic terminals of type A, and both dendritic and axonal terminals of type B--immunostain for one isoform of GAD, GAD67, In addition, we show that type A horizontal cell somas and primary dendrites in the visual streak (identified by their immunoreactivity to calbindin) are immunoreactive for the other GAD isoform, GAD65. Double-labeling experiments for GAD65 and GABA reveal that every cell that stains for GAD65 also stains for GABA. The presence of GAD67 in horizontal cell terminals suggests that rabbit horizontal cells are GABAergic. The segregation of the two GAD isoforms to different cell compartments suggests that GABA is released at different sites, possibly by two different mechanisms.

Noninvasive fluorescence detection of hepatic and renal function

A noninvasive in vivo fluorescence detection scheme was employed to continuously monitor exogenous dye clearance from the vasculature. Differentiation between normal and impaired physiological function in a rat model was demonstrated for both liver and kidney. A fiber optic transmitted light from source to ear; a second fiber optic positioned near the ear transmitted the fluorescent light to a detector system. Two model dye systems were employed in this initial study. Indocyanine green, known to be exclusively cleared from the blood stream by the liver, was excited in vivo with laser light at 780 nm. The fluorescence signal was detected at 830 nm. A characteristic clearance curve of normal hepatic function was obtained. After a partial hepatectomy of the liver, the clearance curve was extended in time, as would be expected from reduced hepatic function. In addition, fluorescein labeled poly-D-lysine, a small polymer predominantly cleared from the blood stream by the kidney, was excited in vivo with laser light at 488 nm. The fluorescence signal was detected at 518 nm. A characteristic clearance curve of normal renal function was obtained. After a bilateral ligation of the kidneys, the clearance curve remained elevated and constant, indicating little if any clearance. Thus, the feasibility of a new noninvasive method for physiological function assessment was established. © 1998 Society of Photo-Optical Instrumentation Engineers.

Quantitative differences in the distribution of zidovudine resistance mutations in multiple post-mortem tissues from AIDS patients

Replication of HIV introduces errors into the genome which are responsible for conferring a growth advantage over wildtype virus when drugs such as zidovudine (ZDV) exert a selective pressure. The molecular basis for HIV-1 resistance to ZDV has been mapped to codons 41, 67, 70, 215 and 219 of the reverse transcriptase gene both in vitro and in clinical samples of blood. This study has investigated the relationship between the quantitative prevalence of ZDV resistance in multiple organs of the same individual. Proviral HIV-1 load was measured by quantitative-competitive PCR in 90 samples from organs of 11 patients dying with AIDS. Nine of these patients had been prescribed zidovudine. The distribution of wildtype and mutant sequences at the positions 41, 67, 70, 215 and 219 of the reverse transcriptase was assessed using a point mutation assay. The results showed that the highest proviral loads were predominately found in lymph node, spleen and lung and there was a significant association between viral load and resistance to ZDV (P=0.008). Inter-organ distribution of wildtype and mutant sequences at codons 41, 67, 70, 215 and 219 was frequently not uniform and in some patients differed markedly between the lymphoreticular system and other organs. These results demonstrate that treatment of HIV-1 infection with zidovudine does not exert uniform selective pressures in multiple organs. These findings have implications for the interpretation of resistance data and design of treatment strategies for HIV, arguing in particular that alterations in therapeutic regimens should consider the likelihood of different resistance patterns being present in multiple sites within the same individual.

The pharmacokinetics of lamivudine in patients with impaired hepatic function

OBJECTIVE

This study was designed to evaluate the effect of hepatic impairment on the pharmacokinetics of lamivudine.

METHODS

Sixteen patients not infected with hepatitis B virus or human immunodeficiency virus who had hepatic impairment due to liver cirrhosis were assigned to moderately or severely impaired groups by clinical signs/symptoms, 14C-aminopyrine metabolic activity and caffeine clearance and compared with eight healthy controls. Following a 300-mg dose of lamivudine, blood and urine samples were taken for drug assay.

RESULTS

Lamivudine was well tolerated in patients with hepatic impairment. There were no statistical differences in overall lamivudine exposure (in terms of AUC or Cmax) or other major pharmacokinetic parameters i.e. CLR, tmax and t1/2, between healthy control subjects and patients with moderate or severe hepatic impairment.

CONCLUSIONS

Hepatic impairment does not warrant dose modification of lamivudine based on this single-dose pharmacokinetic study.

The major late promoter and bipartite leader sequence of fowl adenovirus

The region of the fowl adenovirus serotype 10 (FAV-10) genome containing the major late promoter (MLP) and leader sequences was determined and appropriate genomic fragments were cloned and sequenced. A TATA box was identified and the location of the putative transcription start site was determined. By using synthetic primers from the transcription start site in conjunction with oligonucleotides from the coding regions of the penton base and hexon genes, cDNA was produced from late mRNA isolated from cell cultures infected with FAV-10 at 24 h post-infection. The resulting cDNA was cloned and sequenced and the leader sequences thus identified. It was found that the FAV-10 MLP utilized only two leader sequences (a bipartite leader). By comparison with human adenoviruses (HAVs) it appeared that the second leader in HAVs was absent from the FAV-10. The second leader sequences of FAV-10 was larger than either the second or third leaders of HAVs, but was 29 basepairs shorter than the combined size of the leader sequences 2 and 3 from HAV-2. To confirm the transcription start site and leader sequences, single stranded cDNA was produced from mRNA using the primers from within the coding sequence for the penton base or hexon. A tail of dGTP's was added and cDNA synthesis was completed using an oligonucleotide from within the hexon or penton base coding sequence and a second poly-dCTP oligonucleotide. Sequencing of the resultant G-tailed DNA confirmed the location of the transcription start site as an adenosine residue 24 basepairs upstream from the 3-prime (3') end of the TATA box. Sequencing 5' of the TATA box failed to reveal any sequence similarity with the human adenovirus upstream stimulatory factor (USF). Various plasmids were constructed which placed the determined sequences of the MLP, leader, and the region upstream of the TATA box linked to the co-acetyl acid transferase (CAT) gene. These expression plasmids in transient expression assays of CAT activity in primary chicken kidney cell culture with or without FAV-10 co-infection were determined. These experiments showed that the cassette containing sequences 5' of the TATA box expressed CAT to a much greater level than cassettes not containing this upstream region and that the presence of virus significantly increased the activity of the promoter following the onset of viral DNA replication. Without the 5' region, cassettes failed to express above background levels. These results suggest that the basic structure of the fowl adenovirus MLP is similar to that of the human adenovirus although it utilizes a bipartite rather than a tripartite leader sequence.

Copper, iron, zinc, and manganese in dietary supplements, infant formulas, and ready-to-eat breakfast cereals

High intakes of iron, zinc, or manganese can interfere with copper absorption. Thus, the purpose of this study was to determine whether the amounts and chemical forms of iron, zinc, manganese, and copper added to food products and nutritional supplements might pose a threat to copper status. More than 25% of the vitamin and mineral supplements examined contained no copper, 40% contained the poorly absorbed cupric oxide, and < 30% contained a highly bioavailable form of copper such as cupric sulfate or cupric chloride. Nearly 40% of the prenatal supplements examined contained both iron and zinc without a nutritionally significant amount of copper. More than 80% of the infant formulas examined had ratios of iron to copper exceeding 20:1, which is higher than the recommended ratios of 10-17:1. None of the 40 ready-to-eat breakfast cereals examined were fortified with copper or manganese although 50% of these cereals contained > or = 25% of the reference daily intake for both iron and zinc. Copper availability could be improved by reformulation of several food products and supplements.

Cytomegalovirus polymerase chain reaction viraemia in patients receiving ganciclovir maintenance therapy for retinitis

OBJECTIVES

To determine whether recurrence of polymerase chain reaction (PCR) viraemia during maintenance ganciclovir for cytomegalovirus (CMV) retinitis correlates with (i) CMV disease at a new anatomical site, (ii) progression of the presenting retinitis, or (iii) acquisition of genetic changes in gene UL97 associated with resistance to ganciclovir.

DESIGN

A previously described cohort of 45 patients presenting with first episode retinitis was followed clinically using ophthalmoscopy and serial tests for PCR viraemia for a median of 7 months. CMV viral load and genetic markers of ganciclovir resistance were measured in PCR-positive samples.

METHODS

PCR amplification of the glycoprotein B region of CMV and quantitative competitive PCR assays were employed. Genetic changes in UL97 were identified by sequencing/point mutation assay.

RESULTS

PCR viraemia correlated significantly with new episodes of CMV disease (P=0.011) and a trend was seen for the association with progression of retinitis (P=0.07). Amongst the 14 patients PCR-positive during maintenance ganciclovir, 10 (71%) had genetic markers of resistance. None of these patients became PCR-negative in blood after reinduction ganciclovir therapy compared with three out of four without markers of resistance (P=0.022).

CONCLUSIONS

CMV PCR viraemia correlated strongly with the development of new episodes of CMV disease. Most patients with progression of retinitis remained PCR-negative in blood, consistent with therapeutic failure due to poor intraocular penetration of ganciclovir. However, the minority who were PCR-positive in blood may have reinfected their eye, and frequently had markers of ganciclovir resistance. The implications of these findings for the management of patients with CMV disease are discussed.

Nucleotide sequence of canine herpesvirus homologues of herpes simplex virus type 1 US2, US3, glycoproteins I and E, US8.5 and US9 genes

The partial nucleotide sequence of two BamHI fragments that span the unique short region (US), terminal repeat region (TR) and internal repeat region (IR) of canine herpesvirus (CHV) has been determined. Data obtained revealed several open reading frames (ORF's) identified as the US2, US3, gI, gE and US9 homologues of herpes simplex virus type 1 (HSV1). The CHV homologues also show significant identity in amino acid sequence with those encoded by feline herpesvirus type 1 (FHV1), bovine herpesvirus (BHV1) and equine herpesvirus (EHV1). Translation of another ORF showed little amino acid identity with the gene products of other alpha-herpesviruses. Its genomic position relative to the other CHV homologues would suggest it is the US8.5 gene of CHV.

Nucleotide and amino acid sequence analysis of the 100K protein of a serotype 3 porcine adenovirus

The genomic region between map units 69 and 78 of a type 3 porcine adenovirus (PAV3) was sequenced and analysed. An open reading frame (ORF) of 2514 nucleotides encoding a polypeptide of 838 amino acids and approximately 94.1 kDa was found. The size and location of the ORF suggested it was the PAV3 homologue of the 100K gene and this was confirmed by nucleotide sequence comparison with the 100K of human adenovirus type 2. Amino acid sequence alignment of the predicted polypeptide with the sequences of the 100K proteins of four human adenoviruses and type 10 fowl adenovirus revealed sequence identities of between 31% and 52%. Although amino acid conservation was present throughout the entire sequences compared, lower identity was noted in both the amino- and carboxy-termini.

Rehabilitation outcome of individuals with nontraumatic myelopathy resulting from spinal stenosis

A study was undertaken of 46 patients (19 cervical and 27 lumbar) admitted to an inpatient rehabilitation unit following surgical decompression for myelopathy or cauda equina syndrome resulting from spinal stenosis (SS). Individuals with SS represented 16 percent of all spinal cord injury (SCI) admissions. When compared to patients with traumatic SCI, patients with SS were significantly (t-test, p < .01) older (mean age 68 versus 39 years), more frequently retired/unemployed (89 percent versus 43 percent), more often married (57 percent versus 36 percent) and less often male (54 percent versus 82 percent) but with similar ethnicity. Significant (p < .01) Functional Independence Measurement (FIM) changes for the SS patients were noted after rehabilitation in the categories of self-care, sphincter control and mobility/locomotion. Additionally, outcome comparisons with a group of traumatic SCI patients who had similar motor function revealed similar lengths of stay, discharge FIM scores and discharge-to-community rates. This study suggests that individuals with weakness secondary to SS represent a significant proportion of individuals with SCI, make significant functional gains following inpatient rehabilitation and can achieve functional outcomes similar to those of traumatic SCI individuals.

Changes to the cytokine microenvironment in the genital tract mucosa of HIV+ women

As previous studies have indicated that genital tract mucosal T cell function may be impaired in HIV infection, we investigated the T cell cytokine mRNA in the genital tract mucosa of HIV-infected women to determine if there are alterations in the cytokine profile which may explain the T cell impairment. The in situ hybridization technique was used to investigate the T helper-1 (Th1: IL-2, interferon-gamma (IFN-gamma)) and Th2 cytokine (IL-4, IL-5, IL-10) mRNA profile in cervical biopsies from 10 HIV+ and 10 HIV- subjects. Cervical intraepithelial neoplasia (CIN) and genital infection had previously been excluded and the distribution of immunocompetent cells within the cervical mucosa was known for each subject. Non-parametric tests were used to compare the optical density (OD) of cytokine mRNA in the HIV+ and HIV- groups. Comparisons were also made between peripheral CD4 lymphocyte counts, cervical CD4/CD8 T lymphocyte ratios and cytokine mRNA OD in HIV+ subjects. The HIV+ women had significantly higher mRNA OD for the Th2 cytokines IL-4, IL-5 and IL-10 than HIV women. There was also significantly lower IL-2 mRNA OD in the former group. HIV+ women had lower IFN-gamma mRNA than HIV- women, but the difference was not statistically significant. There was no correlation between cytokine mRNA OD and peripheral CD4 count or cervical CD4/CD8 ratio. The predominance of Th2 cytokines, which are immuno-inhibitory, in the cervical mucosa of HIV+ women may underlie the impaired cytotoxic potential observed in the CD8+ T lymphocytes and may contribute to the susceptibility of HIV-infected women to recurrent genital tract infections and cervical neoplasia.

The incidence of AIDS-defining illnesses in 4883 patients with human immunodeficiency virus infection. Royal Free/Chelsea and Westminster Hospitals Collaborative Group

BACKGROUND

Acquired immunodeficiency syndrome (AIDS)-defining illnesses are known to occur at different levels of immunosuppression, and the incidence of diagnoses may also vary according to the CD4 lymphocyte count strata. Information about the incidence of disease at different levels of immunosuppression would help clinicians monitoring patients and would allow prophylaxis to be targeted at the most appropriate population.

METHODS

Between 1982 and July 1995, 4883 patients testing positive for the human immunodeficiency virus were seen at either the Royal Free or Chelsea and Westminster Hospitals in London, England. The incidence of each diagnosis, both overall and stratified by CD4 lymphocyte count, was calculated using a person-years analysis. Patients who had no CD4 lymphocyte counts measured during follow-up were excluded from the analysis.

RESULTS

During a median follow-up period of 27.6 months, 3875 AIDS-defining illnesses were reported in 1713 patients. The incidence of AIDS-defining illnesses ranged from 6.22 per 100 person-years of follow-up for Pneumocystis carinii pneumonia (95% confidence interval, 5.74-6.70) to 0.37 for extrapulmonary tuberculosis (95% confidence interval, 0.26-0.48). The incidence of each AIDS-defining illness increased as the CD4 lymphocyte count declined; diagnoses such as cytomegalovirus and Mycobacterium avium-intracellulare complex infection had a low incidence at CD4 lymphocyte counts above 0.05x10(9)/L (50/mm3), while Kaposi sarcoma, P carinii pneumonia, and esophageal candidiasis had a high incidence throughout all CD4 lymphocyte count strata.

CONCLUSIONS

This study provides important information about the risk of AIDS-defining illnesses at lower CD4 lymphocyte counts, enabling disease-specific prophylaxis to be targeted at the most appropriate population. In the future, as more prophylactic therapies are developed, this study will provide historical data of the incidence of diseases before specific prophylaxis was introduced.

Changes in lung lymphocyte populations reflect those seen in peripheral blood in HIV-1 positive individuals

We have investigated the level of lymphocytosis present in the lung of human immunodeficiency virus (HIV)-1+ infected patients with and without pulmonary disease and how changes in natural killer (NK), B and T-cells seen in peripheral blood (PB) compare with those seen in bronchoalveolar lavage fluid (BALF). Lymphocyte subpopulations and their expression of activation, cytotoxic markers and memory status were characterized by triple immunofluorescence. Macrophages accounted for over 80% of the BAL cells. Only three out of 72 patients had a lymphocyte percentage >30%. No statistically significant differences in the relative proportions of NK, CD4 and CD8 populations were seen in BALF when compared to PB, except for a twofold increase in the percentage of activated CD8 cells in BALF. The only differences in BALF populations between the HIV-1+ groups were a lower percentage of CD4+ cells, and a higher percentage of activated CD8+ cells in the patients with pneumonitis. In the present cohort of patients there was little evidence for an overall lymphocytosis in bronchoalveolar lavage fluid of HIV-1+ subjects. Changes observed in lymphocyte subsets of bronchoalveolar lavage fluid populations reflected those in peripheral blood, and were similar for patients with and without pneumonitis. Evidence of increased CD8 subset activity in bronchoalveolar lavage fluid did, however, emerge.

Changes in lung lymphocyte populations reflect those seen in peripheral blood in HIV-1 positive individuals

We have investigated the level of lymphocytosis present in the lung of human immunodeficiency virus (HIV)-1+ infected patients with and without pulmonary disease and how changes in natural killer (NK), B and T-cells seen in peripheral blood (PB) compare with those seen in bronchoalveolar lavage fluid (BALF). Lymphocyte subpopulations and their expression of activation, cytotoxic markers and memory status were characterized by triple immunofluorescence. Macrophages accounted for over 80% of the BAL cells. Only three out of 72 patients had a lymphocyte percentage >30%. No statistically significant differences in the relative proportions of NK, CD4 and CD8 populations were seen in BALF when compared to PB, except for a twofold increase in the percentage of activated CD8 cells in BALF. The only differences in BALF populations between the HIV-1+ groups were a lower percentage of CD4+ cells, and a higher percentage of activated CD8+ cells in the patients with pneumonitis. In the present cohort of patients there was little evidence for an overall lymphocytosis in bronchoalveolar lavage fluid of HIV-1+ subjects. Changes observed in lymphocyte subsets of bronchoalveolar lavage fluid populations reflected those in peripheral blood, and were similar for patients with and without pneumonitis. Evidence of increased CD8 subset activity in bronchoalveolar lavage fluid did, however, emerge.

Vigabatrin-associated retinal cone system dysfunction: electroretinogram and ophthalmologic findings

OBJECTIVE

To determine the sources of vigabatrin-associated visual disturbances in patients treated for epilepsy.

BACKGROUND

Vigabatrin is an extremely effective antiepileptic drug that selectively increases brain gamma-aminobutyric acid (GABA). Several patients recently developed constricted visual fields during vigabatrin treatment in the United Kingdom, indicating the possibility of GABA-associated retinal dysfunction.

METHODS

Patients with visual symptoms treated chronically with vigabatrin at our center underwent visual evoked potentials (VEP), electroretinograms (ERG), and visual field and ophthalmologic examinations.

RESULTS

Four of 38 patients treated with vigabatrin developed visual symptoms 2 to 40 months after starting the drug. Two patients complained of constricted visual fields and two had blurred vision. ERG demonstrated evidence of bilateral retinal dysfunction consistent with reduced inner retinal cone response in all four patients. Oscillatory potential responses were lost, suggesting impairment of the highly GABAergic amacrine cells. Two of the patients had normal VEPs and minimal findings on clinical ophthalmology examinations despite abnormal ERGs. Abnormal examination findings were narrowed retinal arteries, surface wrinkling retinopathy, and abnormal macular reflexes. One patient also had reduced rod photoreceptor function in the more symptomatic left eye.

CONCLUSIONS

Visual field constriction and blurring during vigabatrin therapy is associated with retinal cone system dysfunction. Visual symptoms may represent selective vulnerability of retinas of affected patients to GABAergic effects of vigabatrin. The prevalence and course of retinal changes associated with vigabatrin therapy are important to determine in a larger group of patients.

A novel mitochondrial DNA point mutation in the tRNA(Ile) gene: studies in a patient presenting with chronic progressive external ophthalmoplegia and multiple sclerosis

We report a new mutation, a G to A transition at nucleotide position 4298 within the mitochondrial tRNA(Ile) gene in a patient with chronic progressive external ophthalmoplegia and multiple sclerosis. The mutation, which alters an evolutionary conserved nucleotide within the anticodon stem, was heteroplasmic in skeletal muscle but was not present in the patient's blood. Single fibre PCR analysis revealed significantly higher levels of the G4298A mutation in cytochrome c oxidase (COX) negative fibres than in COX-positive fibres. This mutation represents the seventh pathogenic nucleotide substitution to be found in this gene and as such confirms the tRNA(Ile) gene as a susceptible "hot spot" for mitochondrial DNA point mutations. Of particular interest is that this patient has the clinical features of both multiple sclerosis and a mitochondrial DNA disorder.