Evidence for major gene inheritance of Alzheimer disease in families of patients with and without apolipoprotein E epsilon 4

Apolipoprotein E (APOE) genotype is the single most important determinant to the common form of Alzheimer disease (AD) yet identified. Several studies show that family history of AD is not entirely accounted for by APOE genotype. Also, there is evidence for an interaction between APOE genotype and gender. We carried out a complex segregation analysis in 636 nuclear families of consecutively ascertained and rigorously diagnosed probands in the Multi-Institutional Research in Alzheimer Genetic Epidemiology study in order to derive models of disease transmission which account for the influences of APOE genotype of the proband and gender. In the total group of families, models postulating sporadic occurrence, no major gene effect, random environmental transmission, and Mendelian inheritance were rejected. Transmission of AD in families of probands with at least one epsilon 4 allele best fit a dominant model. Moreover, single gene inheritance best explained clustering of the disorder in families of probands lacking epsilon 4, but a more complex genetic model or multiple genetic models may ultimately account for risk in this group of families. Our results also suggest that susceptibility to AD differs between men and women regardless of the proband's APOE status. Assuming a dominant model, AD appears to be completely penetrant in women, whereas only 62%-65% of men with predisposing genotypes develop AD. However, parameter estimates from the arbitrary major gene model suggests that AD is expressed dominantly in women and additively in men. These observations, taken together with epidemiologic data, are consistent with the hypothesis of an interaction between genes and other biological factors affecting disease susceptibility.

Management of thyroid carcinoma with radioactive 131I

PURPOSE

To evaluate the role of radioactive 131I in the management of patients with well differentiated carcinoma of the thyroid.

METHODS AND MATERIALS

Between 1965 and 1995, a total of 117 patients with well-differentiated carcinoma of the thyroid underwent either lobectomy or thyroidectomy followed by 100-150 mCi of 131I.

RESULTS

With a median follow-up of 8 years, only four patients (3%) developed a recurrence of their disease. The 5-year actuarial survival was 97% with a 10-year survival of 91%. There were no severe side effects noted after 131I therapy.

CONCLUSIONS

Radioactive 131I is a safe and effective procedure for the majority of patients with well-differentiated thyroid carcinoma. We currently recommend that all patients undergo a subtotal or total thyroidectomy followed by 131I thyroid scanning approximately 4 weeks after surgery. If the thyroid scan shows no residual uptake and all disease is confined to the thyroid, we recommend following patients with annual thyroid scans and serum thyroglobulin levels. If there is any residual uptake detected in the neck or if the tumor extends beyond the thyroid, we recommend routine thyroid ablation of 100-150 mCi of radioactive 131I.

Transneuronal changes of the inhibitory circuitry in the macaque somatosensory thalamus following lesions of the dorsal column nuclei

The inhibitory circuitry of the ventroposterolateral nucleus (VPL) of the macaque somatosensory thalamus was analyzed in normal animals and in those surviving for a few days or several weeks following a unilateral lesion of the cuneate nucleus, the source of medial lemniscal (ML) axons carrying information from the contralateral upper extremity. Inhibitory synaptic terminals in the VPL were defined as those that contain flattened or pleomorphic synaptic vesicles and that can be shown to be immunoreactive for gamma-aminobutyric acid (GABA). There are two types of these profiles: F axon terminals that arise from neurons of the thalamic reticular nucleus, and perhaps from VPL local circuit neurons (LCNs); and the dendritic appendages of LCNs that form presynaptic dendrites (PSDs). ML terminals normally have extensive synaptic interactions with PSDs but not with F axon terminals. Electron microscopic analyses revealed that cuneatus lesions resulted in a rapid loss of ML terminals and a statistically significant reduction in both F and PSD synaptic profiles. Confocal scanning microscopy also demonstrated a profound loss of GABA immunoreactivity in the deafferented VPL. These changes persisted for more than 20 weeks, without any evidence of reactive synaptogenesis of surviving sensory afferents or of inhibitory synapses. The changes in GABA circuitry are transneuronal, and the possible mechanisms that may underlie them are discussed. It is suggested that the altered GABAergic circuitry of the VPL in the monkey may serve as a model for understanding changes in somatic sensation in the human following peripheral or central deafferentation.

Indirect argon laser drainage of subretinal fluid

We report on a new method of subretinal fluid drainage which uses the indirect ophthalmoscopic delivery of argon laser energy to perforate the choroid. This carries all the theoretical advantages of drainage with the endolaser probe but is simpler and less expensive. We present a prospective series of 31 patients in whom this method was applied. Satisfactory drainage was obtained in 28. There were 4 cases of limited subretinal haemorrhage attributable to the laser, and 1 case of subfoveal haemorrhage. No cases of retinal perforation or incarceration were observed.

Micronucleus induction in human lymphocytes: comparative effects of X rays, alpha particles, beta particles and neutrons and implications for biological dosimetry

The cytokinesis-block micronucleus assay in peripheral blood lymphocytes has the potential for being a simple and rapid method of biological dosimetry. This technique has been used to study the induction of micronuclei in the blood from 12 donors after exposure to a range of radiations with track-averaged LET values ranging from 0.26 to 44 keV microns -1. Data based on the average response of the 12 individuals for 250 kVp X rays were found to agree well with results published previously from other laboratories using similar techniques. Low dose-limiting RBE values relative to 250 kVp X rays for the radiations studied were found to be 0.50 for strontium/yttrium-90 beta particles, 6.9 for 20-23 keV microns -1 alpha particles and 17 for 24 keV neutrons. The pattern of the variation of individual radiosensitivity was found to be complex and dependent on dose, and the evaluation of individual radiosensitivity based on the response at one dose only can be misleading. It is concluded that, although the cytokinesis-block micronucleus assay in blood lymphocytes is a radiobiologically appropriate technique to use for biological dosimetry, its practical implementation may be limited by a need to perform individual pre-exposure calibrations.

Confocal microscopy analysis of living Xenopus eggs and the mechanism of cortical rotation

The dorsoventral body axis in amphibian embryos is established by a rotation of the outer cortex relative to the inner cytoplasmic core. This cortical rotation depends on microtubules and is correlated with a parallel array of microtubules just inside the vegetal cortex. Since the parallel array moves with the inner cytoplasm and most of its microtubules are oriented with their plus ends facing the direction of cortical movement, it has been suggested that plus end-directed motor molecules attached to the cortex drive the rotation by moving along microtubules of the parallel array. Using an inverted confocal microscope to examine living eggs, however, we found that rotation movements precede the formation of a detectable parallel array at the vegetal pole, that the parallel array consists of multiple layers of microtubules at depths ranging from 4 to 8 microns inside the plasma membrane and that the velocity of rotation is immobilized eggs increases with depth in this region. These findings suggest that (1) early cytoplasmic movements are due to something other than the fully formed parallel array and (2) the motor molecules responsible for the bulk of the rotation movement are not restricted to a monolayer at the subcortical interface but may be distributed throughout the parallel array, perhaps causing microtubules to slide along other microtubules by a mechanism similar to that seen in cilia and eukaryotic flagella.

Dosage-sensitive maternal modifiers of the drosophila segmentation gene runt

The protein encoded by the pair-rule gene runt functions as a transcriptional regulator during anterior-posterior patterning of the Drosophila embryo. Results of over-expression experiments as well as parallels drawn from the recent characterization of vertebrate homologues indicate that interactions with other proteins are likely to be central to the function of the Runt protein. To identify factors important for runt activity, we took advantage of an adult visible phenotype observed in animals heterozygous for runt mutations. Using a set of 126 different deficiency chromosomes we screened approximately 65% of the genome for genes that act as dose-sensitive maternal modifiers of runt. Eighteen deficiencies representing 12 putative loci were identified as maternally acting enhancers of runt haplo-insufficiency. Further characterization of two of these regions led to the identification of the interacting loci. Both of these loci affect the spatial regulation of runt transcription and appear genetically complex. Furthermore, the effects of one of these loci, M(1)1B, is indirect and mediated through effects on the transcriptional regulation of posterior gap genes.

Protein-DNA interactions at the major and minor promoters of the divergently transcribed dhfr and rep3 genes during the Chinese hamster ovary cell cycle

In mammals, two TATA-less bidirectional promoters regulate expression of the divergently transcribed dihydrofolate reductase (dhfr) and rep3 genes. In CHOC 400 cells, dhfr mRNA levels increase about fourfold during the G1-to-S phase transition of the cell cycle, whereas the levels of rep3 transcripts vary less than twofold during this time. To assess the role of DNA-binding proteins in transcriptional regulation of the dhfr and rep3 genes, the major and minor dhfr-rep3 promoter regions were analyzed by high-resolution genomic footprinting during the cell cycle. At the major dhfr promoter, prominent DNase I footprints over four upstream Sp1 binding sites did not vary throughout G1 and entry into the S phase. Genomic footprinting revealed that a protein is constitutively bound to the overlapping E2F sites throughout the G1-to-S phase transition, an interaction that is most evident on the transcribed template strand. On the nontranscribed strand, multiple changes in the DNase I cleavage pattern are observed during transit through G1 and entry into the S phase. By using gel mobility shift assays and a series of sequence-specific probes, two different species of E2F were shown to interact with the dhfr promoter during the cell cycle. The DNA binding activity of one E2F species, which preferentially recognizes the sequence TTTGGCGC, did not vary significantly during the cell cycle. The DNA binding activity of the second E2F species, which preferentially recognizes the sequence TTTCGCGC, increased during the G1-to-S phase transition. Together, these results indicate that Sp1 and the species of E2F that binds TTTGGCGC participate in the formation of a basal transcription complex, while the species of E2F that binds TTTCGCGC regulates dhfr gene expression during the G1-to-S phase transition. At the minor promoter, DNase I footprints at a consensus c-Myc binding site and three Sp1 binding sites showed little variation during the G1-to-S phase transition. In addition to protein binding at sequences known to be involved in the regulation of transcription, genomic footprinting of the entire promoter region also showed that a protein factor is constitutively bound to the first intron of the rep3 gene.

An outbreak of cholera from food served on an international aircraft

In February 1992, an outbreak of cholera occurred among persons who had flown on a commercial airline flight from South America to Los Angeles. This study was conducted to determine the magnitude and the cause of the outbreak. Passengers were interviewed and laboratory specimens were collected to determine the magnitude of the outbreak. A case-control study was performed to determine the vehicle of infection. Seventy-five of the 336 passengers in the United States had cholera; 10 were hospitalized and one died. Cold seafood salad, served between Lima, Peru and Los Angeles, California was the vehicle of infection (odds ratio, 11.6; 95% confidence interval, 3.3-44.5). This was the largest airline-associated outbreak of cholera ever reported and demonstrates the potential for airline-associated spread of cholera from epidemic areas to other parts of the world. Physicians should obtain a travel history and consider cholera in patients with diarrhoea who have travelled from cholera-affected countries. This outbreak also highlights the risks associated with eating cold foods prepared in cholera-affected countries.

Analysis and comparison of the mouse and human immunoglobulin heavy chain JH-Cmu-Cdelta locus

We report here 23,686 bases of contiguous DNA sequences from the mouse germline immunoglobulin heavy chain (H) constant (C) mu delta region. The sequence spans the joining (JH) regions, the mu constant region (C mu), the delta constant region (C delta) coding regions, a domain relic, the mu switch region (S mu), seven blocks of simple sequence repeats, a large unique sequence inverted repeat, a large unique sequence forward repeat, and all of the intervening material. A comparison of this 23.7-kb region with the corresponding human C mu/C delta region reveals clear homology in the coding and introns of C mu but not in the 5' flanking J gene segments nor in the intergenic and C delta regions. This mixed pattern of similarity between the human and the mouse sequences contrasts with high levels of similarity found in the T-cell receptor C alpha/C delta region and alpha and beta myosin genes and the very low levels found in the gamma-crystallin, XRCC1, and beta-globin gene clusters. The human and mouse comparison further suggests the incorporation of novel sequences into expressed genes of IgD.

The "revolution" in outpatient care

Although the concept of outpatient care is not a new one, the growth in ambulatory facilities has revolutionized medical care in the United States. The growth in ambulatory surgery centers, imaging centers, and cancer centers in Florida is explored in detail. With the many changes forthcoming in health care, ambulatory care will play an increasing role in delivering good health care at a reasonable cost.

The role of somatosensory information in a constrained locomotor task

The purpose of this project was to study the role of somatosensory information in the performance of a constrained locomotor task by rats and to further examine the influence of structural recovery in the somatosensory thalamus, specifically the ventral posterolateral nucleus (VPL). Groups of rats were trained to traverse an elevated, one inch bar for a reward. The time taken to run across the bar (run time) was used as a measure of the success of the goal-directed behavior. The movement pattern of the hindlimb during the swing phase of the locomotor task was quantified from videotape on Preoperative (PRE) Day 15 and during the 46-day postoperative period. The movement pattern was characterized using six different parameters: the area, the X and Y values of the centroid under the normalized curve of the hindlimb trajectory, the vertical displacement of the hindlimb in the flexion and extension phases of the swing cycle, the maximum instantaneous hindlimb velocity, and the proportion of time spent in the acceleration versus deceleration phases of the swing cycle. In order to disrupt the central pathways for somatosensory information, lesions were made in (i) the right gracile nucleus (GN) (n = 18), (ii) bilateral GN (n = 7), (iii) the right GN and the left VPL (n = 6), and (iv) bilateral VPL (n = 8), and (v) sham-operated animals (n = 5). The run time and the pattern of the hindlimb swing cycle were used as measures of loss and recovery of function. Only the bilateral VPL group showed an impairment in run time and they recovered by Postoperative (POST) Week 4. All groups demonstrated an impairment in initial flexion of the hindlimb during the swing cycle that recovered in the right GN group only. On POST Day 49, the right GN, bilateral GN, and the sham groups received injections of 5% WGA-HRP into both CN to determine the location of these projections in VPL. The CN projections were not redistributed into the gracile area of VPL after GN lesions. Since our previous study (24) had shown the number of synapses in VPL returned to normal after dorsal column nuclei (DCN) lesions by POST Day 50, the recovery of the number of synapses alone was not sufficient to restore the normal gait pattern, while the recovery of the run time preceded the complete recovery of the number of synapses.(ABSTRACT TRUNCATED AT 400 WORDS)

A mitochondrial elongation factor-like protein is over-expressed in tumours and differentially expressed in normal tissues

The tissue-specific expression of an antigen (P43) ubiquitously expressed at high levels in a variety of tumours of human and animal origin was investigated using a monoclonal antibody to P43. Whereas low amounts of P43 are expressed in the spleen, skeletal muscle and pancreas, P43 is abundantly produced in the liver and in other tissues such as the kidney, heart and brain which have levels of oxidative metabolism. Interestingly, a related protein of higher molecular weight is abundantly expressed in the lung and in amounts which were higher than those observed with other tissues. The human cDNA for P43 was isolated from a human liver cDNA library and mapped to chromosome 16 between p11.2 and 12 and also to a position near the centromere on the long arm of chromosome 17. The deduced amino acid sequence of P43 is remarkably similar to that of E. coli EF-Tu and the mitochondrial EF-Tu of S. cerevisiae with the structurally and functionally important amino acids of EF-Tu being completely conserved in P43. A comparison of the distribution of P43 and a mitochondrial protein Hsp 60 among different cellular fractions indicated a likely mitochondrial localisation for P43. Taken together these results suggest that P43 is a human mitochondrial elongation factor.

The control of ventilatory and cardiac responses to changes in ambient oxygen tension and oxygen demand in octopus

Octopus vulgaris can regulate its oxygen uptake down to a PO2 of around 6.7 kPa. As the tension falls from 18.6 to 6.7 kPa (140 to 50 mmHg), Pv (the pressure pulse driving the ventilatory flow, measured inside the mantle cavity) can more than double while fv (the ventilation frequency) increases by a few per cent at most. Both changes are reversed when the ambient oxygen tension is returned to normal. Cutting the visceral nerves linking the hearts and gills to the brain prevents these adaptive changes in Pv and fv, as does section of the branchial nerves linking the cardiac ganglia to the gills. Responses to changes in ambient oxygen tension are very fast, beginning within two or three ventilation cycles. It is concluded that changes to Pv and fv depend upon receptors in the gills and on the integrity of a nervous pathway to the brain. Changes in oxygen tension also affect the hearts, where aortic pulse amplitude (Pa) and, to a lesser extent, heartbeat frequency (fh) fall and rise with the ambient PO2. In this case, section of the visceral or branchial nerves has no effect. Responses are again very rapid. It is concluded that the observed fall and return to normoxic values of Pa and fh are local responses to a fall and rise in the oxygen tension of blood coming from the gills into the systemic heart. Changes to ventilation and heartbeat can also occur in normoxic water when oxygen demand rises after feeding. These responses are not prevented by section of the visceral or branchial nerves. Possible control of ventilation and heartbeat through the neurosecretory system in the anterior vena cava is discussed.

Dendritic outgrowth from neural cells transplanted to the hippocampal fissure

Transplants of cell suspensions that were either selective for granule cells or contained all hippocampal cell types were placed in the hippocampal fissure or in the infragranular cleavage plane (IGCP) of the dentate gyrus. Several transplants were found in both areas in the same dentate gyrus. After a variety of post-transplant survival times, neurons of both the donor and the host were filled with lucifer yellow in fixed sections. Sections were also immunoreacted with antibodies to glial fibrillary acidic protein (GFAP), vimentin, neural cell adhesion molecule (NCAM and HNK-1/NCAM) and were histochemically reacted for ACHE. Dendrites of neurons from transplants of cells of the whole hippocampus usually stayed within the transplant. If a dendrite from such transplants did grow out of the transplant, it grew into the molecular layer (ML) of the host dentate gyrus and not into the hilus of the host. Dendrites from granule cell selective transplants grew into the ML of the host and those that grew from fissure transplants were inverted from the normal orientation of host granule cell dendrites. Dendrites also grew out of the transplant in the absence of reactive gliosis. Transplants of cells from the whole hippocampus placed in the IGCP showed the greatest ingrowth of acetylcholinesterase (ACHE) fibers. In granule cell transplants made concurrently into the fissure and the IGCP, donor granule cell dendrites grew into the host ML from both sites, demonstrating that a gradient of tropic factors across the ML could not account for the direction and orientation of the dendritic outgrowth, since a gradient that directed the growth of one set of dendrites would work against the dendrites growing in the opposite direction.

Elevated levels of shed type II IL-1 receptor in sepsis. Potential role for type II receptor in regulation of IL-1 responses

Two types of cellular IL-1Rs have been characterized and cloned from both human and murine sources. The type II IL-1R has a very short cytoplasmic domain and does not seem to participate in IL-1 signaling. We demonstrate that type II IL-1Rs are released from the surface of neutrophils in response to treatment with TNF or endotoxin. In addition, serum from patients with sepsis syndrome contains elevated levels of soluble type II IL-1Rs. Neutrophils isolated from patients with sepsis have greatly enhanced expression of type II IL-1R mRNA and cell surface receptors and are therefore a likely source for the shed receptors in serum. Of the three forms of IL-1, soluble type II IL-1R binds IL-1 beta with highest affinity and also selectively inhibits IL-1 beta activity. We propose that increased cell surface expression and rapid release of preformed type II IL-1R from neutrophils, as a soluble IL-1 beta binding protein, represents a mechanism that has evolved for regulating IL-1 activity in sepsis.

Elevated levels of shed type II IL-1 receptor in sepsis. Potential role for type II receptor in regulation of IL-1 responses

Two types of cellular IL-1Rs have been characterized and cloned from both human and murine sources. The type II IL-1R has a very short cytoplasmic domain and does not seem to participate in IL-1 signaling. We demonstrate that type II IL-1Rs are released from the surface of neutrophils in response to treatment with TNF or endotoxin. In addition, serum from patients with sepsis syndrome contains elevated levels of soluble type II IL-1Rs. Neutrophils isolated from patients with sepsis have greatly enhanced expression of type II IL-1R mRNA and cell surface receptors and are therefore a likely source for the shed receptors in serum. Of the three forms of IL-1, soluble type II IL-1R binds IL-1 beta with highest affinity and also selectively inhibits IL-1 beta activity. We propose that increased cell surface expression and rapid release of preformed type II IL-1R from neutrophils, as a soluble IL-1 beta binding protein, represents a mechanism that has evolved for regulating IL-1 activity in sepsis.

The purification, cloning, and expression of a novel luteinizing hormone-induced mitochondrial protein in MA-10 mouse Leydig tumor cells. Characterization of the steroidogenic acute regulatory protein (StAR)

The acute response of steroidogenic cells to trophic hormone stimulation is the mobilization of cholesterol from cellular stores to the mitochondrial outer membrane and the transfer of this cholesterol to the mitochondrial inner membrane where the first enzymatic step in steroidogenesis occurs. The transfer of cholesterol across the mitochondrial membranes is dependent upon de novo protein synthesis, and this is the regulated step in the process. Although the newly synthesized regulatory protein(s) have yet to be identified, we previously have proposed a candidate protein which we identified in MA-10 cells that is synthesized in response to luteinizing hormone stimulation and that is localized to the mitochondria. In the present study, we report the isolation of a cDNA that encodes this luteinizing hormone-induced protein. Analysis of the cDNA and protein sequences reveals this is a novel protein. Importantly, we demonstrate for the first time that expression of the protein in MA-10 cells in the absence of hormone stimulation is sufficient to induce steroid production. We conclude that this protein is required in the acute regulation of steroidogenesis and propose to call this protein the Steroidogenic Acute Regulatory protein (StAR).

Thrombin generation in patients undergoing carotid endarterectomy: implications in acute vessel wall closure and antithrombotic therapy

We determined the extent and duration of activation of coagulation during the first 24 hours after carotid endarterectomy. Serial blood samples were collected before, during and after surgery from 10 patients with severe stenosis (> 70%) undergoing carotid endarterectomy with heparinization. Platelet poor plasmas prepared from these samples, were analysed for activated prothrombin fragment F1 + 2 and thrombin-antithrombin III (TAT) levels, using commercially available ELISA kits. F1 + 2 and TATs were measured as indices of thrombin generation and inhibition respectively. Baseline F1 + 2 and TAT levels were 1.19 +/- 0.27 nMol/ml and 17 +/- 10 pMol/ml, respectively. Neither the F1 + 2 nor TAT level increased during surgery at a time when the patients were heparinized. However, both the F1 + 2 and TAT levels increased significantly within 3 hours after surgery and after the heparin had been neutralized with protamine, (p < 0.01). Moreover, both the F1 + 2 and TAT levels remained elevated in 75% of the patients for at least 24 hours, p < 0.01. We conclude that i) thrombin generation is significant post surgery in patients undergoing carotid endarterectomy despite their receiving heparin during surgery; ii) heparin may not be the ideal anticoagulant for carotid endarterectomy; and iii) persistent thrombin generation may contribute to early post-endarterectomy ischemic events.

Observation and measurement of drooling by people with mental retardation

Four brief observational surveys were used to score residents of a state institution for people with mental retardation as drooling/not drooling. An average of 14% of the population was identified as drooling on the occasion of any of the surveys; the accumulated proportion of clients reported as drooling was 28%. In a second study, the drooling of 2 of the clients identified in the first study was sampled within and across days. These clients drooled different amounts both within and between days, which validated their presence and classifications in the first study.

Traumatic lesions and transplants of granule cells in the dentate gyrus alter the distribution of afferent fibers in the molecular layer

The present experiments determined whether traumatic lesions of the dentate gyrus granule cells had a different effect on the afferents in the molecular layer (ML) than nontraumatic lesions. Nontraumatic lesions of the granule cells induced by colchicine, ibotenic acid, x-radiation, and adrenalectomy have been reported to reduce both the acetylcholinesterase (AChE)-positive fibers and entorhinal afferents in the ML. After the nontraumatic granule cell lesions, the laminar distribution of the entorhinal afferents was maintained in the ML, whereas the AChE laminar pattern was lost. In the present study, dentate granule cells were traumatically lesioned by a fluid injection into the infragranular cleavage plane (IGCP) of the dentate gyrus. The traumatic lesion resulted in an altered distribution of the afferents in the ML. The perforant path fibers, shown by injection of wheat germ agglutinin horseradish peroxidase into the entorhinal cortex, occupied a greater proportion of the ML in lesioned animals than in control animals. The normal laminar pattern of AChE-positive afferents was not present after the granule cell lesion. There was an initial increase in AChE-positive fibers in the ML that lasted several weeks but eventually returned to near normal levels. The altered distribution of afferents could in part be due to uneven shrinkage of the molecular layer and/or sprouting of the afferents. Granule cell suspension transplants into the IGCP also traumatically lesioned the host granule cells but immediately replaced the damaged host granule cells with immature granule cells. The distribution of afferents was similar to that found in lesioned-only animals. The traumatic lesion induced MAP2 immunoreactivity in the anisomorphic reactive astrocytes of the ML. At the longer survival times, MAP2 was not seen in either the astrocytes of the ML or in the isomorphic reactive astrocytes in CA3.

The differentiation of dentate granule cells following transplantation

Immature cells transplanted into an adult host must adapt to their new environment. In the present study we have shown the dendritic development of dentate granule cells following transplantation. The adult host granule cells were lesioned by a fluid injection into the infragranular cleavage plane of the dentate gyrus. Few, if any, granule cells survived the lesion and the molecular layer (ML) shrank. When allogeneic neonatal granule cells were included in the fluid, the host granule cells were simultaneously killed and replaced. In order to visualize the dendrites, the granule cells were filled with Lucifer yellow (LY) in fixed sections and subsequently immunoreacted with an antibody to LY. The granule cell dendrites in the transplant were shorter in length, had a greater cross-sectional area, had more spines, and were more coiled and bent than control granule cell dendrites. The dendrites in the transplant formed functional synapses as indicated by cytochrome oxidase histochemistry and the transplant prevented xc03some of the ML shrinkage. Acetylcholinesterase (ACHE) xkreaction product increased both in lesioned and in transplant groups. The laminar pattern of ACHE in the control ML was not seen after the lesion and did not return in animals with successful transplants. We conclude that (i) the dendrites of neurons in the transplant adapted to the adult host environment and a shrinking ML with remarkable structural plasticity; (ii) the transplant prevented some of the shrinkage of the ML; (iii) the transplant could not reverse some of the lesion-induced changes in host organization, such as the organization of ACHE inputs to the ML; and (iv) a phenotypically specific population of transplanted neurons can replace traumatically lesioned neurons of the same type even if the host conditions continue to change.

Flumazenil in cirrhotic patients in hepatic coma: a randomized double-blind placebo-controlled crossover trial

Previous reports have suggested that "endogenous" benzodiazepines could contribute to neural inhibition in hepatic encephalopathy. RO 15-1788 (flumazenil), a specific antagonist of brain benzodiazepine receptors, could thus reverse the neurological symptoms of hepatic encephalopathy. To test this possibility, we conducted a double-blind, placebo-controlled crossover trial of the efficacy of flumazenil in cirrhotic patients in hepatic coma. Seventy-seven cirrhotic patients in hepatic coma were evaluated. Fifty-six were excluded from the trial because of multiorgan failure or because coma was precipitated by prior use of benzodiazepines, and 21 patients were randomly assigned to the flumazenil group (11 patients) or the placebo group (10 patients). Treatment was administered intravenously as a 20-ml solution (placebo or 2 mg flumazenil); seven patients were crossed over. Clinical status was assessed blindly by two observers, using a modified Glasgow scale, every 15 min for 6 hr. Electroencephalogram tracings obtained before and after drug administration were evaluated blindly by two independent observers. Serum concentrations of benzodiazepines before treatment were measured by means of a fluorescence polarization immunoassay. Improvement in neurological symptoms was observed in six patients treated with flumazenil, whereas none in the placebo group showed improvement (p < 0.05; Fisher's exact test). Improvements in electroencephalogram tracings were demonstrated in four patients treated with flumazenil, compared with two patients in the placebo group (p = NS). Benzodiazepines were found in the serum of four patients treated with flumazenil (two responders and two nonresponders); all of these patients had received pharmaceutical benzodiazepines 4 to 6 days before the trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Insertional activation of mevalonate kinase by hepatitis B virus DNA in a human hepatoma cell line

Insertional mutagenesis of growth related genes by hepatitis B virus (HBV) DNA is presumed to play a role in hepatocarcinogenesis. Here, we report on insertional activation of the mevalonate kinase (MK) gene in the human hepatoma cell line PLC/PRF/5. Integration of HBV DNA dissociated the promoter and upstream regulatory elements of the gene from its coding sequences. This led to the over-expression of hybrid transcripts arising from an HBV promoter and the consequent over-production of functionally active mevalonate kinase. MK phosphorylates mevalonate, a major intermediate in the branched cholesterol/isoprenoid biosynthetic pathway. Isoprenylation is crucial to the functions of cellular proteins related to growth control, including the proto-oncogene ras. As the enzymes of these biosynthetic pathways are regulated at multiple points by negative feedback, both transcriptionally and at the protein level, the results discussed here support the idea that aberrant growth could result from deregulated overexpression of MK and, perhaps, other enzymes in the cholesterol pathway. These results invoke novel mechanisms by which cell transformation might occur.

The effects of hydrogen peroxide on steroidogenesis in mouse Leydig tumor cells

It has previously been reported that treatment of rat luteal cells and human granulosa luteal cells with hydrogen peroxide (H2O2) results in a significant inhibition of steroid production. The mechanism of inhibition in the former was found to be at the level of cholesterol transport into the mitochondria, whereas in the latter it was found to be a result of inhibition of one or more enzymes in the steroidogenic pathway. In the present study we examined the effects of H2O2 on hormone-stimulated steroid production in another steroidogenic cell type, the Leydig cell. Our results demonstrate that treatment of either LH- or cAMP analog [(Bu)2cAMP]-stimulated MA-10 mouse Leydig tumor cells with H2O2 results in a dose-dependent inhibition of the production of progesterone (the major steroid produced in MA-10 cells). It was also observed that similar concentrations of H2O2 resulted in a significant inhibition of protein synthesis, a finding which could in part be responsible for the observed decrease in steroid production. Furthermore, although H2O2 resulted in a dose-dependent inhibition of (Bu)2cAMP-stimulated pregnenolone production, addition of the hydroxylated intermediate 22R-hydroxycholesterol and inhibitors of further pregnenolone metabolism demonstrated that cholesterol side-chain cleavage complex activity was unaffected by H2O2. Conversely, incubation of H2O2-treated cells in the presence of pregnenolone resulted in a very significant inhibition of progesterone synthesis. These data indicate that H2O2 inhibits steroidogenesis in Leydig tumor cells primarily by inhibiting the activity of the 3 beta-hydroxysteroid dehydrogenase, but that other effects of H2O2 such as inhibition of protein synthesis and the transfer of cholesterol to the cholesterol side-chain cleavage complex may also be involved.

Site-directed mutagenesis of human thioredoxin. Identification of cysteine 74 as critical to its function in the "early pregnancy factor" system

Thioredoxin has been identified as a key component of the "early pregnancy factor" system, a system of components present in pregnancy sera which expresses a lymphocyte modifying activity in an assay known as the rosette inhibition assay. Although thioredoxin alone is inactive, addition of thioredoxin to lymphocytes in combination with nonpregnancy sera or platelet-activating factor results in a positive response. We have changed several amino acids of human thioredoxin by site-directed mutagenesis to investigate the residues required for this cooperative function. Conversion of the two active site residues (cysteines 32 and 35) to serines results in a protein devoid of classical redox activity; however, this protein retained its ability to cooperate with non-pregnancy sera or platelet-activating factor in the rosette inhibition assay. Vertebrate thioredoxins contain an additional conserved pair of cysteine residues in the C-terminal portion of the protein. Changing both to serines resulted in no change in redox activity but completely abolished function in the rosette inhibition assay. Further study revealed this function was solely dependent on cysteine 74 as conversion of only cysteine 74 to serine abolished function, whereas replacement of only cysteine 70 with serine had no effect. The nonfunctional mutants counteracted the action of pregnancy serum in the assay strongly supporting the hypothesis that thioredoxin is an integral part of the early pregnancy factor system with residue cysteine 74 having an important role.

Neutrophilic eccrine hidradenitis with an unusual presentation

Neutrophilic eccrine hidradenitis (NEH) is an eruption most commonly seen in patients undergoing chemotherapy, and is characterized histologically by a neutrophilic infiltrate around the eccrine coils, with associated necrosis of the sweat coils. The rash usually affects the trunk and extremities, and the morphology of the lesions is very variable. We describe a patient with neutrophilic eccrine hidradenitis who presented with symmetrical, erythematous, swollen ears, a manifestation of NEH which has not been previously reported.

Mutations in the human retinal degeneration slow (RDS) gene can cause either retinitis pigmentosa or macular dystrophy

Mutations in the RDS gene, which encodes the photoreceptor glycoprotein peripherin, have been sought in families with autosomal dominant retinal dystrophies. A cysteine deletion at codon 118/119 is associated with retinitis pigmentosa in one. Three families with similar macular dystrophy have mutations at codon 172, arginine being substituted by tryptophan in two and by glutamine in one. A stop sequence at codon 258 exists in a family with adult vitelliform macular dystrophy. These findings demonstrate that both retinitis pigmentosa and macular dystrophies are caused by mutations in RDS and that the functional significance of certain amino-acids in peripherin-RDS may be different in cones and rods.

Dose- and source-size-related changes in the late response of pig skin to irradiation with single doses of beta radiation from sources of differing energy

Late radiation damage to pig skin has been assessed at 104 weeks after exposure to sources of 90Sr/90Y (Emax 2.2 MeV) and 170Tm (Emax 0.9 MeV). Damage was assessed from measurements of dermal thickness in histological sections of irradiated skin and was compared with that of unirradiated skin to establish the relative reduction in dermal thickness. The size of the source varied from 0.1 to 40.0 mm in diameter; this covered the range of source sizes designed to simulate exposure to radioactive "hot" particles (< or = 1.0 mm diameter) up to the lower range of field size that patients may be exposed to in radiotherapy treatments. Radiation doses were measured using an extrapolation chamber with a collecting electrode of 1.1 mm2, and thus the quoted doses represent an average dose over this area. For the larger 90Sr/90Y sources of > or = 5 mm diameter and the larger 170Tm sources of > or = 2 mm diameter there was no evidence, based on levels of damage consistent with a > or = 10, > or = 20, > or = 30, and > or = 40% reduction in relative dermal thickness, for any effect of source size on the ED50 value for each of these specified levels of effect. However, there was a marked effect of beta-particle energy; the skin surface doses associated with the ED50 values (+/- SE) for a > or = 20% reduction in relative dermal thickness were approximately 12 and approximately 40 Gy for 90Sr/90Y and 170Tm, respectively. This difference in skin surface dose for an equivalent level of dermal injury reflects the variation in the depth dose from these two beta-particle emitters. These skin surface doses, for what was considered to be a clinically detectable dermal effect, were below the ED10 for the early skin response of moist desquamation. This supports the selection of late dermal thinning as the effect on which to base dose limits in radiation protection for more generalized larger area skin exposures. In comparison, single exposures to a small area, from sources designed to simulate those from hot particles, reinforced the view that acute ulceration should be the effect on which dose limitation is based. Either the isoeffect doses for a clinically detectable reduction in relative dermal thickness of > or = 20%, following a single exposure to a small area, were higher than the ED10 for acute ulceration or the area of skin showing dermal thinning was so small that it was not considered to be detrimental.

An approach to training and retaining primary care physicians in rural Appalachia

The West Virginia School of Osteopathic Medicine (WVSOM) educated and retained more primary care physicians for practice in rural Appalachia than did any other U.S. medical school from 1978 through 1990. This article describes the most important methods used at WVSOM to place physicians in rural areas: (1) The school has a focused, achievable mission (to provide primary care physicians who are trained to meet the medical needs of rural Appalachia and to improve the health care of the rural Appalachian population) that is agreed upon by the administration, faculty, and students; (2) it participates in a multistate educational exchange program with a similar mission; (3) it emphasizes personalized and interactive recruiting, admission, and placement processes aimed to attract nontraditional, rural students; (4) it provides early and long-term clinical training in rural sites (both hospitals and physicians' offices); (5) it is dedicated primarily to the education of medical students rather than to research or other goals; and (6) it is a freestanding school in a rural environment. The authors state that although WVSOM is unusual in some respects, at least some of its methods may be useful to other medical schools as they seek to produce more primary care physicians for rural and other underserved areas.

FLUID UPTAKE AND THE MAINTENANCE OF BLOOD VOLUME IN OCTOPUS

The replacement of fluid following withdrawal of up to 40 % of the blood from Octopus vulgaris can be tracked over a period of days by measuring the dilution of haemocyanin, which is not simultaneously replaced. Haemocyanin concentration was measured from the copper content or the oxygen-carrying capacity of further small blood samples. Fluid lost was replaced within 1–2 h, provided that the digestive gland ducts were left intact. If these were ligated, the haemocyanin concentration remained the same as before withdrawal of the initial large blood sample and the animals died within a few hours. Evidence presented elsewhere has indicated that the site of the fluid uptake is the digestive gland appendages. Urine production would be continued or increased during the restoration of blood volume. When urine volume is added to the volume of fluid replaced, it appears that this fluid transport system must be capable of moving at least its own volume of fluid from the gut into the blood every 5 min. An immediate consequence of blood withdrawal is a fall in blood pressure and pulse amplitude, followed within minutes by a transient rise to high blood pressures, apparently as a result of an increase in peripheral resistance as circulation to the arms is restricted, conserving the blood for vital central organs. Following these transient swings, the diastolic blood pressure returns to normal values despite blood loss; pulse amplitude returns as blood volume is replaced. Duct-ligated animals continue to show a reduced pulse.

Long-term symptomless HIV-1 infection in recipients of blood products from a single donor

There have been reported cases of long-term symptomless human immunodeficiency virus type 1 (HIV-1) infection, but it is not clear whether the benign course of infection was due to host, viral, or other unknown factors. During follow-up of subjects with transfusion-acquired HIV-1 infection in New South Wales, Australia, we identified a group of 6 subjects who had been infected through a single common donor. We were therefore able to study the contributions of various factors to the course of infection. Throughout follow-up (range 6.8-10.1 years after infection), 5 of the recipients and the donor (last follow-up 10.2 years after infection of the first recipient) remained clinically free of symptoms, with normal CD4 cell counts and no p24 antigenaemia. HIV-1 was isolated from only 1 recipient; the isolate did not induce syncytia in a SUPT1 co-culture assay and had a limited in-vitro host range. 1 infected recipient (who had received extensive immunosuppressive treatment for systemic lupus erythematosus) developed Pneumocystis carinii pneumonia and died 4.3 years after infection. The frequency of progression to AIDS or a CD4 cell count below 0.50 x 10(9)/l was significantly lower among the 6 subjects with a common donor (1/6) than among 101 other HIV-infected transfusion recipients for whom data from 7 years of follow-up were available (94/101; p less than 0.0001). These findings suggest that the subjects were infected by a less virulent strain of HIV-1. The identification of this group of subjects should stimulate a search for other similar groups, which will provide important information on the immunopathogenesis of HIV-1 disease.

Efficacy of denture cleansing agents in an in vitro bacteria-yeast colonization model

The purpose of this investigation was to develop a new, in vitro bacteria-yeast denture colonization model. Candida albicans and Streptococcus mutans, organisms associated with denture stomatitis, reproducibly colonized denture blanks in high numbers. Both Efferdent and Super-Strength Polident were able to substantially reduce or eliminate colonizing S mutans. In sharp contrast, however, no significant decreases in adherent C albicans were observed with either denture soaking agent.

Evaluation of a photodiode array/HPLC-based system for the detection and quantitation of basic drugs in postmortem blood

A systematic analytical approach has been developed for liquid chromatography determination of a number of basic drugs in postmortem blood. Using selective extraction, that is, back extraction into 0.2N sulfuric acid and 6N hydrochloric acid after the initial extraction with toluene under basic conditions (from 2 mL of blood), basic and weakly basic drugs, such as propranolol and diazepam, can be simultaneously quantitated and identified with a high degree of confidence. A microcomputer-based photodiode array detector was used to evaluate peak purity and facilitate peak identification. An automatic library search was performed at the end of each analysis using the system software. The method was validated for within-day and between-day precision for ten basic drugs at two concentrations. The coefficient of variation for the between-day precision was less than 8.7%. Accuracy of the assay was tested at four concentrations using linear regression analysis. The coefficients of determination (r2) for all ten drugs were greater than 0.99, and their slopes were close to unity. The chromatographic conditions developed are suitable for the screening of several basic, acidic, amphoteric, and neutral drugs. Retention data and ultraviolet spectral data for 119 drugs on two reversed-phase columns, using acidic mobile phases, are also presented.