Clinical experience with atovaquone on a treatment investigational new drug protocol for Pneumocystis carinii pneumonia

The clinical experience of human immunodeficiency virus (HIV) + patients treated with oral atovaquone for acute Pneumocytstis carinii pneumonia (PCP) under a Treatment Investigational New Drug (IND) protocol (mild or moderate PCP) and an Open-Label Study protocol (severe PCP) was evaluated. A total of 940 patients intolerant of or unresponsive to trimethoprimsulfamethoxazole were enrolled from private practices, clinics, and institutional HIV treatment centers in the United States. Demographics data and the history and severity of PCP were collected at enrollment. The number of therapy days, adverse experiences, clinical response to therapy, and mortality were collected at day 21. Reporting of serious, unexpected adverse experiences attributable to therapy was required. Of the 760 (96%) patients with mild to moderate disease for whom follow-up observation was complete, 591 (78%) responded clinically to treatment, 177 patients (23%) discontinued treatment prematurely, and 50 patients (7%) died. Of the 140 patients (95%) with severe PCP with follow-up data, 79 (56%) responded to treatment, 45 (32%) discontinued treatment early, and 53 patients (38%) died. Adverse events that resulted in temporary or permanent discontinuation of therapy included diarrhea, vomiting, elevated liver enzyme levels, nausea, and fever. No serious unexpected adverse events attributable to the drug were reported. The treatment IND mechanism enabled a large number of patients with acute PCP to be treated with this experimental therapy while the drug was under regulatory view.

The crystal structure of p13suc1, a p34cdc2-interacting cell cycle control protein

p13suc1 binds to p34cdc2 kinase and is essential for cell cycle progression in eukaryotic cells. The crystal structure of S.pombe p13suc1 has been solved to 2.7 A resolution using data collected at the ESRF source, Grenoble, from both native crystals and crystals of a seleno-methionine derivative. The starting point for structure solution was the determination of the six selenium sites by direct methods. The structure is dominated by a four-stranded beta-sheet, with four further alpha-helical regions. p13suc1 crystallizes as a dimer in the asymmetric unit stabilized by the binding of two zinc ions. A third zinc site stabilizes the higher-order crystal packing. The sites are consistent with a requirement for zinc during crystal growth. A likely site for p13suc1-protein interaction is immediately evident on one face of the p13suc1 surface. This region comprises a group of conserved, exposed aromatic and hydrophobic residues below a flexible negatively charged loop. A conserved positively charged area would also present a notable surface feature in the monomer, but is buried at the dimer interface. p13suc1 is larger than its recently solved human homologue p9CKS2, with the extra polypeptide forming a helical N-terminal extension and a surface loop between alpha-helices 3 and 4. Notably, p13suc1 does not show the unusual beta-strand exchange that creates an intimate p9CKS2 dimer. p13suc1 cannot oligomerize to form a stable hexamer as has been proposed for p9CKS2.

Severe malaria in children at Port Moresby General Hospital, Papua New Guinea

The demographic and clinical features of severe malaria in children on the south coast of Papua New Guinea have never been clearly documented. This prospective study sought to define the associations between ethnic origin, domain, age, nutritional status and severe malaria in this group and to assess significant clinical features, evaluate the use of a coma score as a prognostic indicator in cerebral malaria and to determine the ultimate outcome. Twenty patients with severe malaria (17 cerebral malaria and 3 severe anaemia) were studied. Their mean age of 4.96 years was significantly greater than that of matched controls with uncomplicated. Plasmodium falciparum infection with mean age 3.79 years (0.02 < p < 0.05). Nutritional status was not a significant independent risk factor when controlled against inpatients with other diagnoses. Low coma scores (Adelaide scale 4/14 or less) sensitively predicted the risk of dying vs survival. The mortality of 18% was comparable with other series. Current standard treatment with quinine and Fansidar was effective and no early recrudescence was encountered in the survivors. The degree of intermarriage and migration between regions precluded firm conclusions from being drawn as to the relevance of ethnic and geographical factors in the epidemiology of severe malaria in this region.

Purification, characterization and analysis of rolipram inhibition of a human type-IVA cyclic AMP-specific phosphodiesterase expressed in yeast

Analyses were done on a human type-IV cyclic AMP (cAMP) phosphodiesterase (hPDE-IVA-h6.1) expressed in an engineered strain of Saccharomyces cerevisiae. This strain (YMS6) expressed soluble PDE activity, together with an insoluble activity which was not released by re-homogenization, treatment with high-ionic-strength solutions or with the detergent Triton X-100. Pellet and soluble PDE activities were typical of type-IV PDE. They were cAMP-specific, insensitive to the addition of either cGMP (1 microM) or Ca2+/calmodulin, and inhibited by rolipram. Thermostability studies showed both activities to decay as single exponentials, indicating the presence of homogeneous PDE protein species in each fraction. Pellet PDE activity was more thermostable than the soluble enzyme. Mg2+ and Mn2+ dose-dependently increased PDE activity and reversed the inactivating effect of EDTA.h6.1 was engineered to express a C-terminal five-histidine motif (h6.1his5). This allowed purification of the PDE to apparent homogeneity in a simple two-step process involving a rolipram affinity column and a Ni2(+)-chelate column. A single monomeric protein of subunit molecular mass approximately 73 kDa and native molecular mass approximately 74 kDa resulted after a approximately 53000-fold purification. This exhibited a Km for cAMP of 8 microM, a true Vmax. of 0.8 mumol of cAMP hydrolysed/min per mg of PDE protein, a kcat. of 3702 s-1, and a value of the specificity constant kcat/Km of 4.6 x 10(8) M-1.s-1, the last implying a diffusion controlled reaction. Rolipram (Ki 0.4 soluble; 0.7 microM pellet) and 3-isobutyl-1-methylxanthine (Ki 15 soluble; 19 microM pellet) served as simple competitive inhibitors for both soluble and pellet forms of h6.1, respectively.

Developing a maternity home care program

Maternity patients are being discharged from hospitals earlier than ever. This maternity care program provides new mothers with comprehensive home care that ensures healthier mothers and babies.

Use of a selective inhibitor of liver carnitine palmitoyltransferase I (CPT I) allows quantification of its contribution to total CPT I activity in rat heart. Evidence that the dominant cardiac CPT I isoform is identical to the skeletal muscle enzyme

It has recently been established that rat heart mitochondria contain two isoforms of carnitine palmitoyltransferase I (CPT I), the minor 88-kDa variant being identical to liver CPT I (L-CPT I) and the dominant 82-kDa form resembling the skeletal muscle enzyme (M-CPT I) (Weis, B. C., Esser, V., Foster, D. W., and McGarry, J. D. (1994) J. Biol. Chem. 269, 18712-18715). To quantify the functional contribution of L-CPT I to overall CPT I activity in heart mitochondria a selective inhibitor of the former was needed. The dinitrophenol analog of 2[6-(4-chlorophenoxy)hexyl]oxirane-2-carboxylic acid (etomoxir) (DNP-Et) was found to have this property. When liver and skeletal muscle mitochondria were exposed to DNP-Et in the presence of ATP and CoASH, the DNP-Et-CoA formed completely inhibited liver CPT I while leaving the muscle enzyme unaffected. Similar treatment of heart mitochondria blocked only the L-CPT I component. This had the effect of shifting the apparent Km for carnitine from approximately 200 to approximately 500 microM and the I50 value for malonyl-CoA (the concentration needed to suppress enzyme activity by 50%) from approximately 0.18 to approximately 0.06 microM, i.e. the heart system now behaved exactly the same as that from skeletal muscle. Taking the Km for carnitine of L-CPT I and M-CPT I to be 30 and 500 microM, respectively, it could be calculated that the former contributes approximately 2% to the total CPT I in heart. When the 82-kDa CPT I isoforms of heart and skeletal muscle were labeled with [3H]etomoxir and then exposed to trypsin, the fragmentation patterns obtained were identical and quite distinct from that given by CPT I from liver. We conclude that (i) DNP-Et, unlike other agents of the oxirane carboxylic acid class, has remarkable inhibitory selectivity for L-CPT I over M-CPT I; (ii) the previously puzzling observation that rat heart CPT I displays kinetic characteristics intermediate between those of the enzymes from liver and skeletal muscle is entirely accounted for by the low level expression of L-CPT I in the cardiac myocyte; and (iii) the dominant 82-kDa CPT I isoform in heart is identical to the muscle enzyme. The data reaffirm that, in contrast to CPT II, CPT I exists in at least two isoforms and that both are present in rat heart.

Cryptococcal meningitis in children in Papua New Guinea: a reminder

Two young males from Central Province were referred to Port Moresby General Hospital with chronic headaches. In each case the initial impression of tuberculous meningitis needed revision in the light of strongly positive cryptococcal serology. Cryptococcal meningitis occurs with sufficient frequency in Papua New Guinea that it should be considered in cases of raised intracranial pressure, ataxia, cranial neuropathy and visual disturbances. Delay in treatment may be disastrous. In contrast to the developed world where fungal meningitides show a predilection for the immunosuppressed, the experience to date in Papua New Guinea is that the majority of cases in both adults and children occur in ostensibly immunocompetent individuals. The epidemiology, clinical course and current treatment of this potentially curable disease are discussed.

Epidemiology of vascular and Alzheimer's dementia among African Americans in Chicago, IL: baseline frequency and comparison of risk factors

We compared demographic, medical, and other epidemiologic factors among 113 African-American Alzheimer's disease (AD) patients and 79 African-American vascular dementia (VaD) patients. The typical background profile of our AD and VaD patients who entered into the study was that of women who were born and raised on farms in the southeastern United States, currently lived in an apartment or home in Chicago with other family members, and were retired, widowed, and had some form of medical insurance. The following distinct patient profiles emerged: (1) African-American AD patients were generally older than their VaD counterparts, more likely to have a family history of AD, Parkinson's disease and dementia, a history of head injury with loss of consciousness and hip fracture, and more severe cognitive impairment and difficulty with instrumental activities of daily living. (2) African-American VaD patients had a higher frequency of cardiovascular disease risk factors and focal neurologic findings, more difficulty with activities of daily living, and a higher frequency of medication use. Differences in risk-factor profile may help explain differential susceptibility by dementia subtype. Since ethnic minorities will constitute a higher proportion of the United States population in the future, targeted epidemiologic research to better understand etiology and risk factors for the dementias of middle and later life among minorities is needed.

Single-cell analysis of intercellular heteroplasmy of mtDNA in Leber hereditary optic neuropathy

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Pharmacology of high-threshold calcium currents in GH4C1 pituitary cells and their regulation by activation of human D2 and D4 dopamine receptors

1. The objective of this study was to characterize the pharmacology of calcium currents in GH4C1 pituitary cells and determine whether activation of heterologously expressed human dopamine receptors can regulate their function. Human D2(short), D3 and D4.2 receptor cDNA's were separately transfected into GH4C1 cells and whole cell calcium currents were recorded by use of nystatin-perforated patch clamp techniques. 2. High-threshold calcium currents were antagonized in a biphasic manner by the dihydropyridine, nisoldipine. The half-maximally effective concentration for each site was 0.2 nM (pIC50 = 9.78 +/- 0.21, n = 4) and 339 nM (pIC50 = 6.47 +/- 0.12, n = 4). The component of current inhibited by 10 nM nisoldipine was also blocked by omega-conotoxin GVIA (30 +/- 9% at 30 nM, n = 6) or by omega-agatoxin IVA (34 +/- 7% at 100 nM, n = 4). 3. Activation of either D2 or D4 receptors by dopamine (10 microM) or quinpirole (0.1 to 10 microM) reduced the peak calcium current by ca. 20% in the majority of cells studied. No inhibition was observed in control or D3 transfected GH4C1 cell lines. 4. The mobilisation of intracellular calcium by thyrotropin releasing hormone in hD4-GH4C1 cells was also studied using Fura-2 AM microspectrofluorimetry. Thyrotropin releasing hormone caused a concentration-dependent increase in calcium mobilisation with an EC50 of 7 nM. D4 receptor activation had no effect upon either basal or hormone-induced [Ca2+]i transients. 5. These results demonstrate that GH4C1 pituitary cells have at least two types of dihydropyridine sensitive high-threshold calcium currents and that like D2 receptors, human D4 receptors can also regulate calcium channel function.

Renal tubular acidosis in Papua New Guinea

Unlike most other inborn errors of metabolism, which require advanced and expensive diagnostic techniques and complex drug and dietary management (often not feasible in developing countries), the renal tubular acidoses may be detected and treated both easily and cheaply. Diagnostic confusion is possible as this series demonstrates due to the protean clinical manifestations. Three recent cases from Port Moresby General Hospital are described and appropriate investigations and treatment discussed.

Hypoxia in childhood pneumonia: better detection and more oxygen needed in developing countries

Even though hypoxia is a major risk factor for death in children with acute respiratory infection in developing countries, oxygen is not part of first line treatment. Because oxygen is not readily available in developing countries it tends to be given to the most seriously ill children, whose outcome is poor. Oxygen might be useful if given earlier in the course of the disease. Clinical signs are not clear cut, however, though the presence of cyanosis and grunting together with a raised respiratory rate can significantly increase the detection of hypoxaemia. A simple oximeter would make detection easier, and oxygen concentrators are more cost effective than bottled oxygen. Ideally oxygen should be given to children in the early stages of clinical pneumonia to prevent deterioration.

Development of tumorigenicity and rearrangement of chromosome 1 correlates with down-regulation of cell-surface glycoproteins in human mammary carcinoma cell line

In the current study, attempts were made to identify any products of normal breast cell genes, that may become inactivated in the malignant counterparts. Using an immune-tolerization/immunization procedure of generating antibody, two different cell-surface glycoproteins termed luminal epithelial antigen, LEA.92 and LEA.135 were identified. LEA.92 and LEA.135 expressions on MEC in a culture model-system, that reflect various steps of neoplastic transformation were detected on normal or immortalized MEC lines that were non-tumorigenic in nude mice. Furthermore, no rearrangement of chromosome 1 was observed in those cells. In contrast, both glycoproteins were undetectable on oncogenically transformed or established lines of mammary carcinoma cells that were tumorigenic. LEA.92 or LEA.135 negative cell lines exhibited a partial deletion of their chromosome 1. In tissue sections, LEA.92 expression was detected on the apical plasma membrane of normal and hyperplastic but not on the malignant mammary or extramammary epithelial cells (MEC). However, unlike LEA.92, LEA.135 was detected on certain cases of primary breast carcinoma cells, irrespective of morphological differentiation, in tissue sections.

Climate change and human history. Some indications from Europe, ad 400-1400

The influence of climate change on history is discussed in such a way as to take account of recent research while seeking to herald, rather than foreclose, the much more focussed and definitive debates that will become possible by the turn of the century. By then, much more elaborated time series of global climatic change over the last several millennia should be available. The period chosen for examination is the 1000 years or so following the collapse of Roman Europe. During this time, civilization seems to wane, wax and wane again, very much in phase with the climate deteriorating, improving and then deteriorating once more. What this overview high-lights is the great vulnerability to climatic perturbation of societies that are marginally poised for other reasons. In several major respects, the whole of world society will be marginal in the 21st century.