Measurement of apolipoprotein B-containing lipoproteins for routine clinical laboratory use in cardiovascular disease.

Although research studies, using complex methods, have shown apolipoprotein B level to be a better marker for coronary artery disease than cholesterol level, it is unclear whether apolipoprotein B level can perform as well when measured by automated clinical laboratory kit methods. The purpose of this study was to determine whether apolipoprotein B level assayed by a kit method is a better marker for coronary artery disease than low-density lipoprotein and total cholesterol levels in patients presenting for angiography. The subjects were two groups of male patients, 44 to 70 years old: 139 with disease and 41 without. Apolipoprotein B level differentiated more than 20-fold better than total or low-density lipoprotein cholesterol levels between the medians of the two groups and showed better diagnostic sensitivity and better diagnostic specificity than total and low-density lipoprotein cholesterol levels. Triglyceride levels were highly significant but showed poorer diagnostic sensitivity than apolipoprotein B level. We conclude that apolipoprotein B level is a more effective marker for coronary artery disease than low-density lipoprotein or total cholesterol levels.


Bilateral mucinous cystadenocarcinoma of the testis and epididymis.

We describe an intratesticular mucinous cystadenocarcinoma in a 59-year-old man. The tumor was bilateral and appeared in the right testis and the left epididymis. The testicular tumor was a well-demarcated nodule, 3.5 cm in diameter, that extended from the lower testicular pole (close to the albuginea) to the epididymis compressing the corpus and infiltrating the cauda. The contralateral tumor, a 2.5-cm nodule located in the corpus epididymidis, compressed the ductus epididymidis. Both tumors consisted of multiple cavities varying in size, separated from one another by connective tissue septa that were incompletely lined by a columnar pseudostratified epithelium. The epithelial cells immunostained positively for carcinoembryonal antigen and comprised two cell types: cells showing a hyperchromatic nucleus, located in the basal portion of the cell, abundant rough endoplasmic reticulum, apical vacuoles, and numerous microvilli; and mucous cells. The cystic lumen showed a mucous content and sloughed epithelial cells. The differential diagnosis and histogenesis of these tumors is discussed.


Acanthamoeba meningoencephalitis in a patient with acquired immunodeficiency syndrome.

Several cases of Acanthamoeba encephalitis (ie, granulomatous amebic encephalitis) have been reported in patients with acquired immunodeficiency syndrome from the United States. To our knowledge, none so far has been reported from Europe, and this is the first case of amebic meningoencephalitis due to Acanthamoeba in a patient with acquired immunodeficiency syndrome from Italy. The patient was a 24-year-old, human immunodeficiency virus-positive heterosexual man with a 6-year history of intravenous drug use. He was admitted to the hospital because of severe headache, confusion, nuchal rigidity, jaundice, and ascites. He died 5 days later. At autopsy, the brain showed extensive hemorrhagic necrosis with numerous trophic and cyst forms of Acanthamoeba. The amebas were identified as Acanthamoeba divionensis by the indirect immunofluorescence test.


Unusual bilateral renal histiocytosis. Extranodal variant of Rosai-Dorfman disease.

A 37-year-old Bangladeshi presented with large bilateral masses involving the hilus of the kidneys. No lymphadenopathy was noted. Nephrectomy was performed. Histopathologically, it revealed a lymphohistiocytic and plasma cell inflammatory tumoral proliferation with characteristic lymphophagocytosis by the S100-positive-CD1-negative histiocytes. Extranodal presentation of sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) should be entertained in the differential diagnosis of bilateral masses involving the kidneys.


Androstenediol regulates systemic resistance against lethal infections in mice.

We previously reported that subcutaneous injection of DHEA (5-androsten-3 beta-ol-17-one, dehydroepiandrosterone) protected mice from lethal infection. This included both a lethal herpes virus type 2 encephalitis and a lethal systemic coxsackievirus B4 (CB4) infection. Androstenediol (5-androsten-3 beta-17 beta-diol, AED), a metabolic product of DHEA is up to 100 x more effective in regulating systemic resistance against lethal infection with CB 4 than its precursor DHEA. Compared to DHEA, treatment with AED was markedly superior in protecting mice against virus induced myocardiopathy, pancreopathy, and mortality. In addition to its protective effect, AED but not DHEA, induced a 3-4 fold proliferation of the spleen and thymus in virus infected animals; this effect of AED was only seen above a certain threshold dose. Neither steroid, however, has shown any significant direct antiviral effect in vitro; similarly, virus tissues titers in vivo are not affected by the hormones. Additionally, both DHEA and AED protected against a lethal infection with Enterococcus faecalis. These observations demonstrate that the steroid hormones DHEA and AED provide a novel approach for prevention and protection of the host from a variety of infectious diseases.


Studies on processing, particle formation, and immunogenicity of the HIV-1 gag gene product: a possible component of a HIV vaccine.

Antigens in a particulate conformation were shown to be highly immunogenic in mammals. For this reason, the particle forming capacity of derivatives of the HIV-1 group specific core antigen p55 gag was assayed and compared dependent on various expression systems: recombinant bacteria, vaccinia- and baculoviruses were established encoding the entire core protein p55 either in its authentic sequence or lacking the myristylation consensus signal. Moreover, p55 gag was expressed in combination with the protease (p55-PR) or with the entire polymerase (p55-pol), respectively. Budding of 100-160 nm p55 core particles, resembling immature HIV-virions, was observed in the eucaryotic expression systems only. In comparison to the vaccinia virus driven expression of p55 in mammalian cells, considerably higher yields of particulate core antigen were obtained by infection of Spodoptera frugiperda (Sf9) insect cells with the recombinant Autographa californica nuclear polyhedrosis (AcMNPV) baculovirus. Mutation of the NH2-terminal myristylation signal sequence prevented budding of the immature core particles. Expression of the HIV p55-PR gene construct by recombinant baculovirus resulted in complete processing of the p55 gag precursor molecule in this system. The introduction of an artificial frameshift near the natural frameshift site resulted in constitutive expression of the viral protease and complete processing of p55, both in Escherichia coli and in vaccinia virus infected cells. Interestingly, significant processing of p55 resembling that of HIV infected H9 cells could also be achieved in the vaccinia system by fusing the entire pol gene to the gag gene. Moreover, processing was not found to be dependent on amino-terminal myristylation of the gag procursor molecule, which is in contrast to observations with type C and type D retrovirus. However, complete processing of p55 into p24, p17, p9 and p6 abolished particle formation. Purified immature HIV-virus like particles were highly immunogenic in rabbits, leading to a strong humoral immune response after immunization. Empty immature p55 gag particles represent a noninfectious and attractive candidate for a basic vaccine component.


Immunological reactivity of a human immunodeficiency virus type I derived peptide representing a consensus sequence of the GP120 major neutralizing region V3.

To reduce the opportunities for human immunodeficiency virus type 1 (HIV-1) to evade vaccine induced immunity, the development of subunit vaccines must focus on the characterization of immunogenic epitopes, which are major targets for the immune system. The most dominant site for elicitation of neutralising immune response is located on the external envelope glycoprotein gp120 within the third variable domain (V3). To overcome virus type specificity of antibodies directed to the V3-domain we designed a 36 amino acids long gp120/V3-consensus peptide (V3-C36) based on published biological data and sequence comparisons of various HIV-1 virus isolates. This peptide contains a conserved core sequence which is suggested to form a surface-exposed beta-turn. This peptide also includes T-cell epitopes defined in mice and humans, an ADCC-epitope and two highly conserved cysteine residues which were oxidized to form a cystine derivate, thus allowing correct peptide folding. In ELISA-tests, this peptide reacts with at least 90% of randomly selected sera of European and African patients infected with HIV-1 and is recognized by three different HIV-1/V3 "type-specific" antisera (MN, RF, IIIB-strain). Using this peptide as immunogen in rabbits, antisera could be raised with highly cross-reactive and HIV-1/IIIB strain neutralizing properties. Moreover, HTLV/HIV-1/IIIB specific cytotoxic T-lymphocytes (CTLs) of BALB/c mice infected with a gp120 recombinant vaccinia virus recognized the central 16- and 12-mer peptides of the V3-C36 consensus peptide in cytolytic assays, indicating perfect compatibility of the consensus peptide with the IIIB-primed CTLs. The DNA-sequence encoding the V3-consensus loop region might be an important component in newly designed recombinant subunit vaccines. In addition, due to its broad serological reactivity, the V3-consensus peptide might play an important role in special diagnostic purposes.


Accumulation of the 126 kDa protein of tobacco mosaic virus during systemic infection analysed by immunocytochemistry and ELISA.

Systemic infection of tobacco with tobacco mosaic virus (TMV) strain WU1, is accompanied by massive accumulation of the virus-coded non-structural 126 kDa protein in X-bodies. The development of X-bodies and the time course of the increase in 126 kDa protein in systemically infected leaves were analyzed by immunocytochemistry and ELISA, respectively, using an antiserum raised against a fusion protein of beta-galactosidase and part of the 126 kDa protein. The ELISA assay developed enabled routine detection of viral 126 kDa (as well as 183 kDa) protein in samples of less than 5 mg of systemically infected leaves. Plants were inoculated by differential temperature treatment, whereafter the accumulation of 126 kDa protein was related to viral multiplication, the development of X-bodies and the formation of symptoms. Both 126 kDa protein and coat protein became detectable between 40 and 66 h after transfer of the plants and increased in parallel up to 200 h. Vein clearing was visible at 66 h, followed by mosaic in the newly developed leaves at 112 h. By electron microscopical analysis small X-bodies, weakly labelled with antibodies against the 126 kDa protein, were detected as early as 24 h after transfer. At this stage they were not associated with nuclei. Thereafter, however, X-bodies increased in size and 126 kDa labelling density, and were increasingly often observed attached to nuclei. In emerging leaves that developed mosaic symptoms, X-bodies were associated with nuclei already at an early stage. These observations are consistent with the hypothesis that association of X-bodies with nuclei may lead to symptom induction, when the leaf is invaded by the virus early in its development.


Detection of chicken anaemia agent DNA sequences by the polymerase chain reaction.

A polymerase chain reaction (PCR) assay was developed for detection of chicken anaemia agent (CAA) DNA. The assay used a single set of 20-base primers complementary to sequences located in the coding regions of the CAA replicative form (RF) DNA genome at positions 485 to 504 and 1048 to 1067. The observed amplification product had the expected size of 583 bp and was confirmed to derive from CAA RF DNA by a unique Hind III restriction enzyme cleavage pattern. The amplified fragment was shown to be specific for CAA RF DNA after chemiluminescence dot blot hybridisation with a digoxigenin-labelled 25-base internal probe. The optimised PCR assay was specific for CAA and highly sensitive, being able to detect a single CAA-infected MDCC-MSB1 cell and at least 100 fg of CAA RF DNA. Preliminary results also showed that the PCR assay can detect CAA DNA in clinical specimens from chicks experimentally infected with CAA.


Turnip yellow mosaic virus variants produced from DNA clones encoding their genomes.

Full-length dsDNA clones that encode the genomes of two Australian turnip yellow mosaic isolates, TYMV-BL and TYMV-CL have been constructed. These clones were transcribed to give 6.3 kb capped ssRNA which infects Chinese cabbages to give symptoms indistinguishable from those produced by the parental viruses. Extensions of up to 26 nucleotides at the 3' end of the TYMV-BL clone delay infections, but virus particles isolated from these plants 4 weeks after inoculation contain RNA with the original TYMV-BL 3' terminus. A 90 nucleotide-long portion of the virion protein gene of TYMV-BL was replaced by a synthetic 90-mer primer with 16 nucleotide changes to decrease the large cytosine content (34-42%) characteristic of tymovirus genomic RNA. No reversion of any of the mutated nucleotides to cytosine occurred during 7 passages in Chinese cabbage. Hybrids between the TYMV-BL and TYMV-CL clones were also constructed, by exchanging various portions of the genome. However, it was not possible to determine definitively which part of the viral genome is responsible for the more severe symptoms caused by TYMV-BL as the hybrids gave intermediate symptoms.


Partial DNA cloning and sequencing of a canine parvovirus vaccine strain: application of nucleic acid hybridization to the diagnosis of canine parvovirus disease.

The cloning and sequencing of an Eco RI-PstI fragment derived from the replicative form of a canine parvovirus (CPV) vaccine strain are reported. The variability of the 5' end of NS 1 protein gene in the genome is confirmed by comparison with previously determined DNA sequences. A 15 nucleotide deletion was also observed in this vaccine strain. In order to improve CPV diagnosis, radioactively labelled RNA or DNA and biotin labelled DNA obtained by random priming of the recombinant plasmid were used as probes mainly on gut or stool samples from naturally infected dogs. Results of filter hybridization correlated well with histopathological diagnosis of parvovirus infection and with hemagglutination tests performed on dog faeces. We propose that nucleic acid hybridization may be an alternative diagnostic method to ascertain the presence of CPV, especially in frozen samples.


Tick-borne encephalitis virus interaction with the target cells.

The binding of tick-borne encephalitis virus to porcine kidney embryo cells was studied. Anti-idiotypic antibodies against TBE virus E protein precipitated gp110 kDa which is predicted to be a cellular receptor for TBE virus.


Some biological properties of a rhabdovirus isolated from penaeid shrimps.

Some of the relevant biological properties of a rhabdovirus isolated from penaeid shrimps (RPS) were examined. The virus replicated in an established fish cell line, epithelioma papulosum cyprini (EPC) which allowed for the development of a quantitative plaque assay protocol. Virus replication was not inhibited by the DNA antagonist, 5-bromo-2'-deoxyuridine (20 micrograms/ml). Virus infectivity was sensitive to 20% ethyl ether, low pH, and to 37 degrees C. The virus showed marked lability to repeated freezing and thawing and storage at -10 degrees C, but was stable at -70 degrees C for several weeks. The virus particle to infectious unit ratio in EPC was found to be 30.


Nucleotide sequence comparison of the 3'-terminal regions of severe, mild, and non-papaya infecting strains of papaya ringspot virus.

The 3'-terminal 2,561 nucleotide residues of the severe HA strain of papaya ringspot virus (PRSV) was determined. Comparison with the published sequence of the mild strain PRSV HA 5-1 showed that they shared a 99.4% identity in their 3'-terminal 2,235 residues. There were ten residues different at the NIb gene, resulting in five amino acid changes, and two residues different in the coat protein gene, resulting in two amino acid changes. The 3'-untranslated regions were identical, but HA contained two more nucleotides (AG) at the 3' extreme. Comparison with the published non-papaya infecting type W strain PRSV-W revealed that they shared a 97.9% identity in their 3'-terminal 2,235 residues. There were 40 nucleotides different in the coding region, which resulted in four amino acid changes in the NIb gene and six in the CP gene, and seven nucleotides different in the 3'-untranslated region.


Eosinophils as host cells for HIV-1.

Transient expression of HIV-1 p24 antigen was observed in eosinophils acutely infected with the HTLV-IIIB strain of HIV-1. PCR analysis of eosinophils isolated from 18 seropositive individuals showed HIV-1 sequences to be present in 2 subjects. These data suggest that eosinophils may act as host cells for HIV-1.


Cloning of the thymidylate synthetase gene (thyPIG 3) from the Bacillus subtilis temperate phage IG 3.

The thyPIG 3 gene from Bacillus subtilis bacteriophage IG 3 was cloned in the plasmid pHV 33. Two recombinant plasmids, pISL 61 and pISL 62 carrying that gene are effective in transforming to thymine prototrophy both Escherichia coli (by complementation) and B. subtilis (by complementation and recombination). The comparison of cloned fragment containing the thyPIG 3 gene and the thyP 3 gene from phage phi 3 T, by restriction analysis and DNA hybridization, suggests a strong homology between the two. The thyPIG 3 gene was mapped in this study in the central region of the IG 3 genome.


Molecular cloning and physical mapping of bovine herpesvirus 4 strain DN 599 and comparison with two American field-isolates.

Ninety four percent of the genome of bovine herpesvirus 4 (BHV-4) strain DN 599 was cloned and a physical map was constructed by Southern blot analysis using a library of cloned fragments cleaved with the 3 restriction enzymes (Eco RI, Bam HI, and Hin dIII). The genome length was estimated to be 156.5 kbp +/- 0.7. The genome comprises a region of unique segment (114 kbp) and two flanking segments containing tandem repeats. The size of each repeat was approximately 2.35 kbp and each repeat contained one Eco RI site and two Bam HI sites. We also examined two recent American field-isolates of BHV-4 and compared the Eco RI maps of the two isolates with that of DN 599. We observed the following: (1) insertions or deletions of restriction sites at the periphery of the unique segment; (2) variation in the lengths of junction fragments; (3) variations in the lengths of hypermolar Eco RI fragments containing the repeats; and (4) the Eco RI map of one of the American field-isolates resembles the BHV-4 "Movar type" of Europe.


Laparoscopic cholecystectomy for acute cholecystitis.

Sixty-eight cases of acute cholecystitis managed by laparoscopic cholecystectomy (LC) are reviewed. Thirty-two patients were admitted up to 10 days after onset of symptoms and 31 were completed by LC. One patient was referred from intensive care with gangrenous acalculus cholecystitis and was completed by LC but required subsequent laparotomy to control a bleeding omental vessel. Five patients were admitted with recurrent attacks of pain and histology confirmed resolving acute cholecystitis. Thirty patients had LC on routine operating lists, having recently had pain within 10 days of admission. Histology confirmed acute cholecystitis or resolving acute cholecystitis in these patients. All were completed by LC. Laparoscopic cholecystectomy is a very effective treatment for acute cholecystitis if complete dissection of anatomy can be performed.


Laparoscopy-guided percutaneous cholecystolithotomy: an evolving technique.

Gall-bladder conservation therapy has been evolving during the past decade. Popular techniques of conservative therapy are extracorporeal shock wave lithotripsy (ESWL) and medical dissolution therapy. The limitations of these procedures have prompted a search for alternative techniques, particularly in relation to percutaneous stone extraction. The cases of four patients with symptomatic gallstones who underwent percutaneous cholecystolithotomy under laparoscopic guidance are reported. The gall-bladder was punctured with a long needle and the tract dilated so that a nephroscope could be introduced. Three cases required stone fragmentation by an ultrasonic lithotripter before removal. Postoperative recovery was uneventful in all cases.


The role of manometry, electromyography and radiology in the assessment of faecal incontinence.

The results of laboratory investigations in 156 patients presenting with faecal incontinence are reviewed to see if and how these investigations supplement a careful clinical evaluation, and in particular to see if they help in the practical management of the problem. All patients underwent anal manometry, and in addition 52 underwent anal sphincter electromyography and 27 defaecatory proctography. Anal manometry quantified sphincteric weakness, and proved superior to digital assessment in this regard. Resting and squeeze pressures were less in those with complete than those with partial incontinence but the differences were not statistically significant. The measurements of rectal sensation and compliance were not additionally helpful. Single fibre electromyography provided the best measure of denervation with re-innervation and was abnormal in about 85% of the group studied. Jitter studies were unhelpful. Most patients had some abnormality on defaecatory proctography but clinical significance could not be established. The choice of treatment was made on clinical grounds and was not influenced by these investigations.


The role of manometry, electromyography and radiology in the assessment of intractable constipation.

An analysis is made of functional studies performed in 96 constipated patients to see how these studies influenced the choice of surgical treatment. All patients underwent anal manometry, and other investigations included colonic transit studies (56), anal sphincter electromyography (42) and defaecatory proctography (34). Additionally nine patients underwent full thickness rectal biopsy. The resting anal canal pressures of the patients studied were lower than controls, and fibre density studies on electromyography were abnormal in half the patients studied suggesting a degree of denervation of the sphincter muscles, which possibly related to chronic straining on the toilet. There was evidence of reduced rectal sensation as shown by an increase in the least perceived volume on balloon distension of the rectum, and in those with megarectum and/or megacolon an increase in maximum tolerated volume. The recto-anal inhibitory reflex was used to screen for adult Hirschsprung's disease, but in one patient the reflex was present despite absence of ganglia on full thickness rectal biopsy indicating the need for biopsy as the definitive diagnostic procedure. Delayed colonic transit using radio opaque markers was a necessary requirement before recommending colectomy, and delayed transit was demonstrated in 34% of the patients studied. Anismus on electromyography was found in 20% of the patients but there was poor correlation with failure of the anorectal angle to widen when bearing down on proctography. The investigations helped in the choice of treatment, but were difficult to interpret. They should be used in severe constipation when surgery is being contemplated.


A new technique of ankle arthrodesis.

A new technique of ankle arthrodesis is described and the results of 12 consecutive procedures are assessed. The method described employs three cannulated transfixion screws and an anterior approach to the ankle. Eleven of the 12 ankles proceeded to solid fusion. One patient developed a painless fibrous non-union. There were no other significant complications. This simple technique provides good compression and adequate resistance to rotatory and angulatory stresses about the ankle fusion site.


Laparoscopic fundoplication: a preliminary report of the technique and postoperative care.

The technique of laparoscopic fundoplication and its hospital management are described. Thirty day results in seven patients demonstrate the decreased insult to the patient, early discharge and early return to usual function, similar to that seen in laparoscopic cholecystectomy.


Oesophageal atresia: the first survival in the Southern hemisphere.

The first known survival in the Southern hemisphere following a corrective operation for oesophageal atresia, is reported. Contrary to previous reports, this survival was in 1948 not in 1949 and the survival occurred in New Zealand not in Australia.


Venous occlusion: a rare complication of transvenous cardiac pacing.

Venous occlusion is an uncommon complication of transvenous cardiac pacing. Fibrotic occlusion of the right subclavian and innominate veins and stenosis of the left innominate vein, after the insertion of transvenous pacing wire, was corrected surgically with an external iliac vein graft.


Torsion of the vermiform appendix: a case report and review of literature.

A case of torsion of the vermiform appendix is described. It is a rare cause of an acute abdomen with a clinical presentation that is indistinguishable from acute appendicitis.


Duplication of the proximal colon mimicking volvulus: a case report.

The case of a 56 year old female with intermittent pain, weight loss, anaemia, and a palpable tympanic abdominal mass is reported. Barium enema showed a very redundant loop of proximal colon, which was thought to have undergone recurrent volvulus. At colonoscopy, the findings seemed normal, but a much shorter length of colon was intubated to the caecum than expected from the barium findings. The duplicated colon was discovered only intra-operatively. This unusual diagnosis should be considered when a barium enema shows a long redundant colon which is not confirmed on colonoscopy.


The pigmentary dispersion disorder in USAF aviators.

The pigmentary dispersion syndrome (PDS) can have serious ocular consequences. Visual changes due to glaucoma and the treatment required can threaten the high level of visual function necessary in military aviation. We reviewed the records of 50 aviators with PDS who were evaluated at the Aeromedical Consultation Service (formerly the USAF School of Aerospace Medicine) over the past 10 years. At last evaluation, 48 were still qualified to fly. Only two aviators were permanently removed from flying duties due to glaucoma. Initial intraocular pressures, cup-to-disc ratios, and refractions were not statistically correlated with progression to glaucoma, but sample sizes were small. At final evaluation, 20 of the 34 aviators with follow-up had glaucoma and required medication. Thirteen eyes underwent laser trabeculoplasty. With appropriate management, the majority of aviators with PDS were able to safely continue their flying careers.


The effects of pyridostigmine bromide on visual performance.

The effects of pyridostigmine bromide (PB) on selected visual functions were measured on four healthy aviator candidates. Following a pretreatment day during which baseline measurements were completed, subjects were administered currently recommended doses (30 mg, t.i.d.) of PB for 3 d during which their visual functions were assessed using a repeated measures design. Spatial resolution ability was evaluated with high and low contrast visual acuity charts and contrast sensitivity charts at three luminance levels. Dark adaptation was evaluated by measuring visual thresholds for 40 min after a standardized retinal photopigment bleach. Also, refractive error and several oculomotor functions (lateral phoria, fusional vergence, accommodative amplitude, and pupil size) were measured. On days that the subjects ingested PB, only refractive error and pupil diameter were significantly different, and these only minimally. We conclude that the use of PB at doctrinal doses will not significantly compromise an aviator's visual ability.


Visual scene effects on the somatogravic illusion.

This study attempted to determine which visual scene cues are most effective in overcoming the somatogravic illusion (SGI), a form of spatial disorientation that occurs when a shift in the resultant gravitoinertial force vector created by a sustained linear acceleration is misinterpreted as a change in pitch or bank attitude. Nine subjects were exposed to a gravitoinertial force shift of -30 degrees in the pitch plane, both with their eyes closed and while viewing computer-generated visual scenes through a wide field-of-view head-mounted display. The scenes depicted acceleration over a shoreline by means of horizon, texture, perspective, and color cues that were presented both in isolation and in various combinations. None of the scenes significantly reduced the magnitude of the SGI relative to the eyes-closed (baseline) pitch illusion, even though the textured scenes produced some linear vection. It remains to be established whether low-cost head-mounted visual displays can reliably reduce the magnitude of the SGI and other spatially disorienting illusions.


Limited heat transfer between thermal compartments during rewarming in vasoconstricted patients.

Thermoregulatory vasoconstriction may serve to separate and limit heat transfer between peripheral and central thermal compartments, in effect providing a thermal buffer for central temperature. We hypothesized that thermoregulatory vasoconstriction would limit heat transfer to the central compartment in patients warmed cutaneously. Hypothermic patients (central temperatures < 35 degrees C) recovering from surgery were randomly assigned to receive forced-air warming (n = 6) or warmed cotton blankets (n = 6). The forced-air warmer delivers approximately 50 W of heat, compared to a heat loss of approximately 50 W with warmed cotton blankets. Despite a significantly greater increase in mean skin-surface temperature with forced-air warming, central temperature in the two groups did not significantly differ. All patients vasoconstricted and there was no difference in oxygen consumption between groups. These data confirm that thermoregulatory vasoconstriction limits heat transfer from peripheral to central thermal compartments and impedes skin surface warming of the body core.


Comparison of four noninvasive rewarming methods for mild hypothermia.

Four noninvasive rewarming techniques for mildly hypothermic subjects were compared. Seven subjects were cooled in a water bath of 15 degrees C for 2 h to an average esophageal temperature (Tes) of 36 degrees C. Thereafter, the subjects were rewarmed by immersion of the body in a water bath of 42 degrees C (Method 1), the body but not the extremities in water of 42 degrees C (Method 2), only the extremities in water of 42 degrees C (Method 3), or spontaneous rewarming in blankets (Method 4). Method 1 showed the highest rewarming rate in Tes (10.1 degrees C/h) and an afterdrop in Tes of 0.18 degrees C. Method 2 showed the same afterdrop, but a lower rewarming rate (7.5 degrees C/h). In Method 3, the heat uptake of the extremities was too low to rewarm the subjects effectively. The afterdrop and rewarming rate were 0.38 degrees C and 0.8 degrees C/h, respectively. Method 4 had the lowest rewarming rate (0.2 degrees C/h), and an afterdrop (0.14 degrees C) which was not significantly lower than that of Method 1 or 2. Therefore, Method 1 is recommended for rewarming mild hypothermic subjects because of its high rewarming rate and small afterdrop.


Decrement in manual arm performance during whole body cooling.

Six subjects performed three manual arm tasks: 1) prior to immersion in 8 degrees C water; 2) soon after immersion to the neck, but prior to any decrease in core temperature; and 3) every 15 min until core temperatures decreased 2-4.5 degrees C. The tasks were speed of flexion and extension of the fingers, handgrip strength and manual dexterity. There was no immediate effect of cold immersion; however, all scores decreased significantly after core temperature decreased 0.5 degrees C. Further decrease in core temperature was associated with a progressive impairment of performance, although at a slower rate than during the first 0.5 degrees C decrease. Flexion and extension of the fingers was affected relatively more than handgrip strength or manual dexterity. Decrement in performance is a result of peripheral cooling on sensorimotor function with a probable additional effect of central cooling on cerebral function.


Thermogenesis induced by inhibition of shivering during cold exposure in exercise-trained rats.

The present investigation was conducted to examine the role of nonshivering and shivering thermogenesis caused by cold exposure in exercise-trained rats. Wistar rats were divided into warm-acclimated (WA), exercise-trained (ET) and cold-acclimated (CA) groups. The trachea was cannulated and a ventilator was connected under light anesthesia and in the supine position. Shivering, oxygen consumption, colonic temperature, blood glucose, and free-fatty acids were measured at 25 degrees C and then at 0 degrees C room temperatures. D-tubocurarine chloride (curare, 0.04 mg/100 g body weight, ip) was given to inhibit muscular activity. Cold-induced oxygen consumption in the ET and WA groups did not decrease when shivering was inhibited, whereas it increased in the CA. The magnitude just after shivering onset for the ET and CA groups as significantly greater than for the WA group. Colonic temperature at the onset of shivering was significantly higher in the WA group than in the ET and the CA groups. The blood glucose concentration during cold exposure and curarization was elevated in the ET group, and did not change in the CA or WA groups. The present results suggest that endurance training at a thermoneutral environment increases cold-induced thermogenic capacity in rats, which may be attributed to preferential carbohydrate utilization.


Heat stress in protective clothing: validation of a computer model and the heat-humidity index (HHI).

Ability to work while wearing protective clothing is often limited by rising body temperature. Peterson analyzed the combined effects of heat, humidity and workload using the Texas Model of Thermoregulation and suggested that environmental heat load imposed on a person wearing heavy, semipermeable clothing could be predicted using the Heat-Humidity Index (HHI = 0.5 Tdb + 0.5 Twb), where Tdb = dry bulb temperature and Twb = wet bulb temperature. Our study was designed to: 1) test the validity of this computer model; and 2) evaluate the applicability of the HHI to heavily clothed subjects working in a variety of thermal environments. Nine men wearing chemical defense clothing were each studied under eight conditions over the range Tdb = 20 - 40 degrees C, Tbg = Tdb + 5 degrees C, relative humidity = 9-75%, and oxygen uptake = 14-27 ml.kg-1 x min-1. Variables analyzed included tolerance time (TT), rectal temperature (Tre), skin temperature, heart rate (HR), weight loss, sweat rate, evaporation rate, and evaporative efficiency. Experiments were designed to last 30-180 min, and continued until Tre = 39 degrees C except when subjective tolerance limits occurred first (12 of 72 experiments). The observed time to reach Tre = 39 degrees C bracketed the predicted time in the more severe conditions, but the model seriously underestimated heat storage in the milder conditions.(ABSTRACT TRUNCATED AT 250 WORDS)


The effects of chronic hypoxia on human auditory system sensitivity.

We have examined the effects of prolonged periods of hypoxia produced at high altitudes on the latency of the auditory brain-stem evoked response (ABER) in 9 subjects at around sea level, 3,500 m, and 4,370 m. Following an ascent from 1,300 m to 3,500 m over 24 h, the mean blood O2 saturation fell to 86.5 +/- 1.2% (+/- S.E.M.) and was associated with a mean prolongation of latency of wave V of the ABER of 0.34 +/- 0.10 ms (p = 0.011 two-tailed paired t-test). Using the stimulus-level/response latency relation determined at around sea-level for each subject, this prolongation of wave V corresponded to a mean reduction in sensitivity of 9.1 dB +/- 1.6 dB. Over a period of 72 h, blood O2 saturation improved slightly (mean 88.1% +/- 1.8%) and mean wave V latency returned to control values. A second rapid ascent to 4,370 m reduced blood O2 to below prerecovery levels (82.5% +/- 1.7%), but in this case there were no significant changes in auditory sensitivity (p = 0.79 two-tailed paired t-test). These data show that mild hypoxia results in an initial decrease in auditory sensitivity. However, the recovery of sensitivity with more prolonged exposure suggests that the auditory system can compensate for chronic mild hypoxia.


The role of ground level oxygen in the treatment of altitude chamber decompression sickness.

Most published reports on the treatment of altitude-induced decompression sickness (DCS) deal exclusively with patients treated with hyperbaric oxygenation. Little information exists on the role of normobaric (ground level) oxygenation as a primary treatment modality for altitude-induced DCS. This study reports the U.S. Air Force experience in the treatment of Type 1 altitude chamber DCS with ground level oxygenation (GLO2) during the period 1 January 1989 to 31 December 1991. Data collected included age, sex, time of symptom development, type of initial treatment, and response to GLO2 administration. There were 221 cases of Type 1 DCS, of which 46 were treated with compression therapy without initial use of GLO2. Of the 175 cases treated with GLO2, 40 failed to resolve and were treated with compression therapy. The remaining 135 cases all resolved with GLO2, obviating the need for HBO therapy. Only 8 patients had a recurrence of symptoms after resolution with GLO2, all of which subsequently resolved with compression therapy. Factors associated with a favorable response to GLO2 are discussed.


Myocardial infarction occurring at the conclusion of centrifuge training in a 37-year-old aviator.

In September 1988, the U.S. Air Force instituted routine centrifuge training for aircrew involved in high performance, high G aircraft. As of June 1991, 6,078 aircrew members have been trained. This report documents an anterolateral myocardial infarction that occurred in a 37-year-old pilot immediately after his centrifuge training profile. The individual had a history of elevated lipids and smoking, and was on a waiver from the USAF for Flying Class II duties for hyperlipidemia treated with cholestyramine.


Ethical concerns in the practice of military aviation medicine.

Military aviation physicians are frequently placed in conflicting ethical situations regarding the areas of patient loyalty, confidentiality, and reporting of findings or hazards. The American College of Occupational and Environmental Medicine has developed a set of guidelines for ethical conduct to assist physicians providing occupational health services. This paper attempts to show that these guidelines can be applied similarly by physicians providing aeromedical services. These guidelines can be helpful in resolving ethical dilemmas that can occur in the daily practice of aviation medicine.


Recent developments in U.S. Air Force pilot candidate selection and classification.

Recent U.S. Air Force policy decisions regarding Specialized Undergraduate Pilot Training (SUPT) have eliminated the need to classify pilot candidates into training specialties prior to entering primary jet training. Under the new system, specialized training assignments will occur at the completion of primary jet training and will be based on flying and academic performance, student preferences, and aircraft availability. Another significant change to the SUPT program was the development of a refined pilot candidate selection model that reduced potential threats to test compromise and gaming strategies.


Kelly's hospital ship.

The JN-4 "Jennie" and DH-4 air ambulance conversions used by the U.S. Army during the period 1918-1924 are well-known to those interested in the history of air evacuation. However, another "unknown" craft was also used during this period. The author unravels the mystery of this craft converted for use as an air ambulance at Kelly Field, TX.


Cases from the aerospace medicine residents' teaching file. Case #52. A flyer with syncope.

The clinical presentation, evaluation, and diagnosis of various types of syncope were discussed. The case also demonstrates the aeromedical management and disposition. This case was unique in that the aviator was initially denied a waiver and permanently grounded, but later returned to flying status.


Time course of aggressive arousal in female hamsters and male rats.

This study replicates previous reports which show that allowing a female hamster to carry out an attack on a conspecific increases its aggressive arousal, i.e., transiently decreases the latency and increases the probability of an attack on a second trial. We now report that attack priming also occurs in male rats. Interpolating delays of 0, 10, 30, and 90 min between the first and second trials resulted in similar patterns of temporal changes in hamsters and rats. The differences in gender, housing condition, and other factors make the parallel in the time course of aggressive arousal in these two rodent species quite striking. The results rule out a simple model of exponential decay with a short time constant. Carrying out an attack sets in motion a complex set of internal events that affect subsequent aggressive behavior similarly in hamsters and rats.


Anterograde and retrograde enhancement of 24-h memory by glucose in elderly humans.

The present experiment examined anterograde and retrograde enhancement of memory storage by glucose in elderly humans. Glucose (50 g) or saccharin was administered shortly before or immediately after acquisition of a narrative prose passage. Recall was tested 24 h later. Glucose administration before or after presentation of the material to be learned significantly improved recall 24 h later compared to performance in the saccharin condition. These findings suggest that glucose retroactively enhances memory storage processing in elderly humans and that the enhancement of memory outlasts the transient elevations in blood glucose levels after glucose ingestion.


Regulation of rat maternal behavior by broadband pup vocalizations.

Pups emit a broadband vocalization ranging from 2 to 40 kHz that generally occurs when the mother sits or steps on her pups. In an earlier study (Ihnat, White, and Barfield, under review), we noted that the mother was more likely to move on the pups and step on them when she was temporarily deafened with ear plugs. This research was extended in the present study by using two different methods to prevent 2-day-old pups from emitting broadband vocalizations. In the first experiment, the female was presented with six of her pups for a 10-min test. In half the tests, the pups had been anesthetized with pentobarbital; in the other half, the pups received saline. In the second experiment, females were presented with pups whose mouths had been sealed with an adhesive substance. In a final study, pups received the adhesive substance on their ventral surface as a control. When the pups were unable to vocalize, there was an increase in the amount of time per bout that the mother spent in incidental contact with her pups; in the sham condition, however, there was no change in her behavior. In addition, the female was less likely to group all her pups within the 10-min duration of the test when the pups could not call. Since pups emit primarily broadband vocalizations in response to handling prior to 4 days of age, broadband calls appear to reduce incidental contact and facilitate retrieval into a group.


An ephemeral sex pheromone in the urine of female house mice (Mus domesticus).

From previous research, the ultrasonic vocalizations of male mice (Mus domesticus) to female mouse urine were hypothesized to be learned as a result of classical conditioning during adult heterosexual encounters. According to this interpretation, a previously neutral conditioned stimulus in female urine comes to elicit vocalizations as a result of its association with some other unknown unconditioned stimulus associated with adult females. However, the research from which this hypothesis was derived utilized urine collected from females housed in metabolic cages. Three experiments further examined the classical conditioning hypothesis using two types of female urine: (i) metabolic-cage-collected urine and (ii) freshly voided urine. Experiment 1 demonstrated that, in contrast to vocalizations to metabolic-cage-collected urine, adult heterosexual experience was not necessary for males to vocalize to freshly voided female urine. In addition, unlike metabolic-cage-collected urine (Experiment 3), freshly voided urine remained a potent stimulus for eliciting vocalizations during repeated testing (Experiments 2 and 3). Finally, freshly voided urine appeared to cause a previously neutral stimulus (cotton swab) to acquire ultrasound eliciting properties (Experiment 2). We suggest from these findings that two chemosignals that elicit vocalizations from males may exist in female mouse urine: (i) a potent, but volatile or easily degraded, unconditioned stimulus to which males vocalize without sexual experience and (ii) a nonvolatile, chemically stable conditioned stimulus.


Those cheating rats: male and female rats use odor trails in a water-escape "working memory" task.

Three-month-old Sprague-Dawley rats were trained on a working memory win-stay (spatial delayed matching-to-sample) water-escape task with the escape platform location the same for all subjects on a given trial, a procedure that maximizes the buildup of an odor trail to the escape platform. In subsequent tests during which the location of the escape platform varied randomly between subjects, the rats, especially the females, while continuing to perform above chance level, made increased errors. Varying the platform location between subjects eliminated odor trail as a nonambiguous cue for locating the escape platform. In a second experiment females performed better than males on a reference memory odor trail discrimination task which involved following the path of like-gender "pathmaker" rats to the escape platform. The relatively poor use of odor trails by the males was associated with a high frequency of choosing a preferred choice section or returning to the choice section selected first on the immediately preceding trial (perseveration). Collectively, the two experiments demonstrate that rats can use either working memory or odor trails to locate an escape platform in a water maze, and that they, especially females, will use odor trails in a working memory task if odor trails are available. Clearly, the location of the escape platform should be varied randomly between subjects in tests of working memory.


Persistence of chronic nicotine-induced cognitive facilitation.

Nicotine has been found in a variety of species and behavioral paradigms to improve memory performance. The beneficial effect of nicotine has been seen after both acute and chronic administration. Interestingly, improved performance has been seen 24 h after acute injection and for at least 2 weeks after chronic administration. However, it is not clear from previous studies whether the persistence of the improved performance represents a true carryover of the drug effect or is due to the behavioral experience while under nicotine's effect. The current study was conducted to determine whether the facilitating effect of nicotine on learning and memory performance could be seen after withdrawal even if there was no behavioral training during the period of chronic nicotine administration. Rats were administered nicotine chronically for 3 weeks but were not tested during that time. Starting 1 week after withdrawal they were trained on a working memory paradigm in an eight-arm radial maze. The nicotine-treated rats started out at control-like levels of performance, but showed significantly faster learning as detected by three different measures of choice accuracy. By the final phase of testing the control subjects had caught up with the nicotine-treated rats. After the acquisition phase, acute challenges with the nicotinic and muscarinic antagonists, mecamylamine and scopolamine, did not elicit any differential effects in the nicotine-treated and control groups. The current study demonstrated that nicotine-induced cognitive facilitation persists for at least 4 weeks after withdrawal and does not depend upon behavioral test experience under the influence of the drug. The mechanism for this persisting effect is not currently understood.(ABSTRACT TRUNCATED AT 250 WORDS)


Short forms of the "reference-" and "working-memory" Morris water maze for assessing age-related deficits.

Short forms of the reference- and working-memory versions of the Morris water maze, each limited to 10 trials, were examined for their reliability and sensitivity to age-related deficits in 16- and 24-month F-344 rats, relative to 2- to 2.5-month young controls. The reference-memory task used long intertrial intervals of 23 h, but required learning only one target location, while the working-memory task used shorter intertrial intervals of 60 min but required learning many different target locations. The reference-memory task was very reliable, revealed large age-related deficits, and correctly identified almost all aged rats as impaired relative to young controls. The working-memory task was less reliable, revealed smaller deficits than the reference memory task at 24 months, and did not discriminate as well between 2.5- and 24-month rats. Furthermore, in the working-memory task 16- and 24-month rats had longer swim paths than 2- to 2.5-month rats on the first trial of each trial pair, which is suggestive of a deficit in processing spatial information and raises questions about the validity of this test as a specific test of working memory. Although the working-memory procedures may be preferable under certain conditions, perhaps as a measure specific to hippocampal dysfunction, the reference-memory task seems more sensitive to age-related deficits and more accurately identifies older rats as impaired. These results are consistent with previous reports that age-related deficits in acquiring spatial learning tasks are common and that the magnitude of the deficit increases as the length of the retention interval increases.


Effects of protein malnutrition and the administration of cortisol on the reflexologic development in rats.

The use of neurological tests in various states of undernutrition has confirmed the presence of delays in reflex ontogeny. Glucocorticoid administration in conditions of normal nutrition produces diminished growth and alterations in brain development similar to those observed in malnutrition, but there is not enough evidence about its effect on reflex development. In addition, some facts lead us to think that the use of permissive doses of these hormones during gestation could alleviate some of the effects of protein malnutrition on the development of pups. In the present study the ages at which certain reflexes appeared in the offspring of Wistar rats (Rattus norvegicus) fed a 20% (N) or 10% (M) protein diet from a week before conception to the end of lactation were observed. Each dietary group was subdivided into two: mothers receiving a daily injection during gestation either of a 0.9% NaCl (S) solution or of a 0.5 mg/100 g weight hydrocortisone acetate (C) solution. Results showed that the NS group of pups generally presented earlier ages of appearance of the variables under study than the remaining groups. Pups of the NC group presented delays in the age of appearance of reflexes. Finally, protein malnutrition delayed the appearance of reflexes and this effect seemed to be attenuated by treatment with hydrocortisone. Thus, hydrocortisone administration in protein malnutrition conditions seems to be beneficial although the results are harmful when administered under normal nutritional conditions.


Strategy selection in a task with spatial and nonspatial components: effects of fimbria-fornix lesions in rats.

The main purpose of the present research was to investigate the ability of rats to learn a 12-arm radial maze task that requires the concurrent utilization of both spatial and intramaze cue information. The task involves in a single trial both place and cue learning as well as reference memory (RM) and working memory (WM). Since the animal can choose place and cue arms in any order, the strategies employed to learn the task can be studied as well as the kinds of memory errors that are made. The results of Experiment 1 showed that the number of errors made on the place and cue components of the task did not differ, and that more RM than WM errors were made early during learning. As the task was learned, the animals tended to choose the place arms before choosing the intramaze cue arms, thus suggesting that a spatial strategy was employed first followed by a cue strategy. In Experiment 2 lesions of the fimbria-fornix resulted in temporary impairments in both RM and WM that were especially apparent on the spatial component of the task. The lesioned rats also switched from choosing mostly place arms early during the trial to choosing more cue arms. While fimbria-fornix lesioned rats recovered from the memory impairments with training, the change in response strategy persisted throughout postoperative testing. The procedure of combining both spatial and non-spatial components concurrently in the same task should prove of value in studying response strategies in animals.


Role of the cerebellum in spatial orientation in the rat.

Adult DA/HAN strain rats were submitted to a spatial orientation task consisting of finding a reward in an open field. They were first submitted to an initial learning session and 10 days later to a retrieval test. The animals were divided into four groups of five rats each: animals that were cerebellectomized before the initial learning session or after the initial learning session, sham-operated rats, and control (intact) animals. Different parameters that characterize the spatiotemporal organization of the rat's exploratory behavior were quantified. From the results, it can be concluded that the cerebellum is not absolutely necessary in the processes that sustain spatial learning but that it is involved in the mechanisms sustaining focused spatial memory and in the cognitive processes of the motor program elaboration and not only in the regulation of the movement being done.


The involvement of the hypothalamic preoptic area on the regulation of thirst in the rat.

Acute reversible lesion in the medial preoptic area (MPOA) by unilateral injection of the local anesthetic lidocaine chlorhydrate (1 microliter, 20 ng/microliters) causes a transient increase in water intake induced by water deprivation in rats. Since lidocaine suppresses the nervous activity, leaving intact fibers of passage and blood vessels, the results suggest an intrinsic inhibitory action of the MPOA on the regulation of water intake. Drinking elicited a return to volumes similar to those of control rats, 3-4 h after lidocaine administration. Lidocaine released into the lateral preoptic area (LPO) slightly decreased or did not change water intake, as compared with controls. The urinary excretion in the MPO group was higher than that of the controls and the LPO, while this last group excreted significantly less urine. The ablation of the POA with lidocaine suggests that the medial aspect of the POA has an intrinsic inhibitory factor influencing drinking, while the lateral aspect did not show a relevant effect.


Effects of aging on the diurnal pattern of water intake in rats.

This study was undertaken to confirm previous findings that Long-Evans rats exhibit age-related changes in the diurnal/nocturnal distribution of water intake and to examine the circadian pattern of these age-related changes. Twenty-one aged and 10 young pathogen-free rats were continuously monitored for water consumption over 12:12 h light/dark cycles. ANOVA, profile analysis, and cosinor analysis each demonstrated that aged rats differed from young rats. The age-related changes in circadian pattern can be described as a blunted rhythm (decreased amplitude) and an altered timing of peak activity (advanced acrophase). These differences, however, were only apparent in a subset of aged rats with the remaining aged rats exhibiting a circadian pattern indistinguishable from that of the young group.


Reversible inactivation of the nucleus of the solitary tract impairs retention performance in an inhibitory avoidance task.

Several peripherally acting hormones and drugs are known to modulate memory storage processes, yet the mechanisms which permit these agents to influence memory is not well understood since they do not freely enter the brain. The nucleus of the solitary tract (NTS) is one brainstem structure which receives important neural input from the periphery. Therefore, the objective of this experiment was to determine whether the NTS is involved in modulating processes contributing to memory formation. Male Sprague-Dawley rats were trained in a one-trial inhibitory avoidance task (0.35 mA, 0.5 s footshock). Immediately or 2 h after training microinjections of 2% lidocaine hydrochloride (20 mg/kg) or a phosphate buffer solution were administered bilaterally into the NTS. Two other groups received microinjections of lidocaine into the fourth ventricle or cerebellum. On retention tests given 48 h after training the latency to reenter the dark compartment of the apparatus was recorded. The retention latencies of rats receiving bilateral microinjections of 0.5 microliter of lidocaine hydrochloride into the NTS were significantly shorter than those of animals given injections of a buffer solution (0.5 microliter), delayed injections of buffer or lidocaine, or control injections of lidocaine into the cerebellum or fourth ventricle. These findings suggest that memory storage processes are impaired by reversible inactivation of the NTS after training. The implications of these findings in terms of a possible role of the NTS in modulating brain processes involved in memory storage are discussed.


An analysis of behavioral plasticity in male Caenorhabditis elegans.

Caenorhabditis elegans is a simple soil-dwelling nematode which has two sexes, hermaphrodite and male. The male C. elegans is differentiated from the hermaphrodite by the presence of 14 sensory structures in the tail. In this study, we compared the behavioral responses of males and hermaphrodites to head-touch and to tap. We hypothesized that the anatomical difference in sensory structures might result in behavioral differences in the reversal response to vibratory stimulation (a tap to the side of the holding dish). In the response to increasing intensities of tap, both sexes showed an increase in response magnitude, with the males showing larger responses than hermaphrodites. In addition, the male was shown to be capable of simple nonassociative learning: it demonstrated habituation and recovery from habituation in a similar manner as the hermaphrodite. Tail-touch-induced inhibition of the reversal response appeared to be similar in males and hermaphrodites. The evidence suggests that the touch withdrawal circuit in hermaphrodites is also present in the male C. elegans, and that the subtle differences in response to tap seen in males may result from the additional sensory receptors of the copulatory bursa of the tail. It seems clear from these studies that these structures do not play a key role in the male worm's response to tap.


Reinstatement of latent inhibition following a reminder treatment in a conditioned taste aversion paradigm.

Reminder treatments have been shown to facilitate the retrieval of a variety of conditioned responses. Whether or not similar results would occur with an experimental paradigm which involves primarily memory for a stimulus, i.e., where no particular response is specified, is unclear. Accordingly, using Sprague-Dawley rats, we employed a latent inhibition paradigm with a long (10 days) retention interval between sucrose (CS) preexposure and sucrose-illness pairing (training). The results demonstrated a loss of latent inhibition following the 10-day retention interval suggesting "forgetting" of the CS preexposure. However, placing a single reminder exposure to the CS within the preexposure-to-training interval reinstated the preexposure effect. Controls indicated that in the absence of the initial preexposure the reminder per se did not produce latent inhibition. Thus, a reminder can reinstate a stimulus attribute (flavor representation) and explicit conditioned responses.


Conditioned taste aversions support drug discrimination learning at low dosages of morphine.

The present experiment shows that a conditioned taste aversion procedure can support discrimination learning at dosages of morphine comparable to those required to produce motivational effects. Sprague-Dawley rats were injected with 4.0 mg/kg morphine sulfate prior to a saccharin-lithium chloride pairing, and physiological saline prior to a saccharin-saline pairing. The rats avoided the saccharin solution following the administration of morphine and consumed significantly more saccharin following saline administration after four discrimination cycles. After this initial discrimination the subjects were trained with progressively lower doses of morphine. Discrimination learning was apparent at doses of 2.0, 1.5, 1.0, 0.75 and 0.5 mg/kg. Animals initially trained with 1.0 mg/kg morphine also learned the discrimination but required 10 training cycles. After this initial discrimination the subjects were trained with progressively lower dosages of morphine and showed a discrimination at a dosage of 0.5 mg/kg.


Hepatic accumulation of alpha-aminoisobutyrate in the pregnant rat at term.

In vivo measurements of the tissue accumulation of alpha-amino[1-14C] isobutyrate ([1-14C] AIB) clearly indicate that the hepatic accumulation of the amino acid is not increased in the fed late pregnant rat. Starvation induced an increases in the hepatic AIB accumulation both in virgin and late pregnant animals, thus suggesting that AIB accumulation by the liver is dependent on food intake. The results suggest that amino acids are similarly directed to the conceptus and the liver during late gestation in the rat.


Glycogen metabolism during human liver development.

Development of enzymes of glycogen metabolism in human fetal and neonatal liver was investigated. Glycogen was present in quantitatable amount from early gestational age onwards; however, ultrastructurally it could not be detected earlier than 20 weeks. Increase in glycogen synthetase a activity during 21-36 weeks of gestation subsequently resulted in glycogen accumulation. A rapid degradation of this glycogen storage, at birth, was accompanied by an elevation in glycogen phosphorylase a activity. The present investigation to be the first to provide a complete profile of glycogen storage and differentiation of glycogen metabolising enzymes in preparing the prenatal fetus for its independent nutritional life.


Post-transcriptional control of H3 histone variants synthesis.

In cultured HeLa cells the rates of H3.1 and H3.2 synthesis measured by pulse labeling experiments reflect the steady state content of the two histone variants. This pattern, however, is largely modified when histone translation is carried out in vitro on RNA isolated from the same cell line. In vivo, H3.1 and H3.2 are synthesized approximately at the same rates while the product of H3 mRNA translation in vitro is mostly represented by H3.1 histones. Factors which have so far been invoked for the control of histone messenger RNA stability and translation efficiency are not sufficient to explain our data which in addition indicate that histone H3.1 and H3.2 have different roles in the organization of the genetic material.


Improved production and purification of interferon-alpha-4a using a T7 RNA polymerase expression system.

An improved method for the synthesis and purification of human interferon-alpha-4a is presented. Interferon-alpha-4a was prepared using a T7 RNA polymerase expression system, where it was expressed from the vector pET-3a. Biologically active interferon-alpha-4a was isolated from the E. coli cells and purified using protamine sulphate precipitation, anion-exchange chromatography and affinity chromatography utilising a monoclonal antibody specific for human interferons-alpha.


Enhancing potency of liposomal monensin on ricin cytotoxicity in mouse macrophage tumor cells.

Monensin, a carboxylic ionophore, which is known to disrupt intracellular trafficking of proteins was intercalated in liposomes and its effect on the stability of liposomes and cytotoxicities of ricin and Pseudomonas exotoxin A in mouse macrophage tumor cells J774A.1 was studied. Stability of liposomes containing monensin was comparable to liposomes without monensin. The cytotoxicity of ricin and Pseudomonas exotoxin A was significantly enhanced by 1nM liposomal monensin (15.7 and 3.6 fold respectively). The enhancing potency of monensin in neutral and negative vesicles was found to be similar, while it was drastically reduced in positive vesicles. The specific uptake of 125I-gelonin from neutral and negative vesicles was not significantly different, whereas from positive vesicles no uptake was observed. Serum strongly influenced the binding at 4 degrees C of positive vesicles as well as the enhancing potency of monensin in these vesicles. Monensin in neutral and negative vesicles significantly reduced the lag period of ricin action, while in positive vesicles, it had no effect. These studies clearly indicate that liposomes could be used as a delivery vehicle for monensin.


Studies on the entrapment and stability of liposomes containing sulfatide from human brain.

Reverse-phase evaporation vesicles containing cerebroside sulfate (sulfatide) from human brain were prepared and their stability and efficiency for entrapment of bovine serum albumin were studied. It has been found that increasing the content of sulfatide from 0 to 15 mol% in the vesicles increases the encapsulation for bovine serum albumin by 0.7- to 3.1-fold, depending on the ratio of solvent:buffer used during liposome preparation. The presence of sulfatide also enhances the stability of the liposomes. Our results suggest that the ability of sulfatide to increase the captured volume and to bring charges to membrane surface may be responsible for the increased protein encapsulation and stability of the sulfatide-containing reverse-phase evaporation vesicles.


Structure-activity relationship for ETB agonism in truncated endothelin-1 analogs.

The essential part of the ETB-selective agonist N-acetyl-GluAlaValTyrPheAlaHisLeuAspIleIleTrp (N-Ac-4AlaET-1(10-21)) for ETB agonism was studied by single amino acid replacement. Single L-alanine substitutions at positions 14, 17, 20 and 21 and the corresponding D-amino acid substitutions at positions 14 and 16-21 resulted in remarkable decreases in ETB binding activity. Furthermore, these analogs elicited endothelium-dependent vasorelaxation in parallel with ETB binding activity. These data indicate that the amino acid residues of Phe14, Leu17, Ile20 and Trp21 and the backbone structure at Phe14 and His16-Trp21 in ET-1 are important for ETB agonism.


EDTA induces differentiation and suppresses proliferation of promyelocytic leukemia cell line HL-60--possible participation of zinc.

Effects of ethylenediaminetetraacetic acid (EDTA), a chelator of divalent cations, on the proliferation and differentiation of human promyelocytic leukemia cell line HL-60 were examined. Incubation of HL-60 cells with 200 microM of EDTA suppressed cell proliferation, and induced differentiation assessed by reductivity of nitro blue tetrazolium and activity of alpha-naphthyl butyrate esterase. These effects were inhibited by zinc (Zn) dose-dependently at concentrations of up to 20 microM, but not by other divalent cations including Ca, Mg, Fe, Cu, Ni, or Cd. Although addition of 200 microM EDTA for 24 hr decreased the c-myc mRNA level of HL-60 cells, coaddition of 20 microM of Zn also reversed this effect on c-myc mRNA level. Treatment with EDTA did not change the half-life time of degradation of c-myc mRNA after addition of actinomycin D (5 micrograms/ml). These findings suggest that Zn deficiency suppresses c-myc gene transcription which is followed by suppression of proliferation and induction of differentiation of HL-60 cells.


Reduction of nitrofuran compounds by heart lipoamide dehydrogenase: role of flavin and the reactive disulfide groups.

In order to elucidate the mechanism of the biological activation of nitrofurans, the interaction of these compounds with lipoamide dehydrogenase (LipDH)** was investigated. LipDH catalysed one-electron reduction of several nitrofuran derivatives. The reaction could be demonstrated spectroscopically and was enhanced by cadmium, arsenite and anaerobiosis. The role of flavin in the nitroreductase activity was supported by (a) the nitrofuran effect on the spectral properties of anaerobic, arsenite-inhibited, NADH-reduced LipDH; (b) FAD catalytic activity in a NADH-nitrofuran model system; and (c) the nitroreductase activity of LipDH monomer. Two-electron nitrofuran reduction to less oxidized products was inhibited by cadmium, arsenite and NAD+. The possible role of reactive nitrosofuran derivatives as intermediates of the nitrofuran reduction sequence was supported by the LipDH capability for catalysing 2-nitroso-1-naphthol redox-cycling. The nitroso naphthol reduction was inhibited by cadmium and arsenite, like the two-electron nitrofuran reduction.


Heparin stimulates the collagen synthesis in mineralized cultures of the osteoblast-like cell line, MC3T3-E1.

We found that heparin induced an increase in collagen synthesis in MC3T3-E1 cells cultured for 15 and 30 days. Northern blots showed that the effect of heparin on the collagen synthesis was mediated through the mRNA expression of type I collagen (day 15). Although heparin stimulated collagen synthesis over and above that stimulated by the transforming growth factor (TGF)-beta, heparin did not stimulate TGF-beta binding. This study indicates that heparin has special tasks both in bone formation and resorption, since it has the ability to form and degrade collagen. We suggest that heparin assists the regulation of collagen metabolism at bone resorption sites.


One-step purification of E. coli elongation factor Tu.

The tuf A gene, encoding the E. coli elongation factor Tu, was cloned in the pGEX gene fusion system. Upon expression EF-Tu is fused to glutathione-S-transferase serving as a purification handle with affinity for glutathione immobilised on agarose. This allows purification of EF-Tu in a one-step procedure. The construct was designed in order to make possible the release of authentic EF-Tu by cleaving the fusion protein with the protease factor Xa.


Speech-language pathologists in the schools.

This data page profiles speech-language pathologists working in school facilities. Of particular interest is an examination of differences between those employed in preschools versus other school facilities. Andrea K. Blake is coordinator of ASHA's research division.


What do you know? What do you need to know?

This article is meant to serve as a general overview of the ADA and the regulatory areas that have the greatest implications for audiologists and speech-language pathologists. If you would like more detailed information, copies of the regulations and technical assistance are available from federal agencies (See Table 1) and through federally funded ADA technical assistance grants (See Professional Practices Perspective). Now it's time for a retest on the quiz.


Standards for professional service programs in audiology and speech-language pathology.

In the June/July 1991 issue of Asha, the Council on Professional Standards published for comment proposed revisions of the standards for American Speech-Language-Hearing Association (ASHA) Professional Services Board (PSB) accreditation. The council considered all of the comments received, made appropriate revisions, and took final action on the revised standards, which will become effective on January 1, 1994. The new standards and implementation statements related to each standard are provided in the following sections. The Standards represent requirements that must be met by all applicants. Implementation Statements are designed to interpret and supplement the standards by providing examples, referencing relevant policy or guideline statements, or specifying types of data or other documentation relevant to a specific standard. The implementation statements were developed by the PSB and have been reviewed by the Council on Professional Standards.


[Observation on malaria transmission intensity at a stone-pit of the mountain area in Baoan County, Guangdong Province].

Zhangshubu stone-pit in Baoan County is located in the mountain area. The workers' camps are 2-3 km away from the village. In a recent survey, in malaria peak season (June, July, August) An. anthropophagus accounted for 87.7% (1059/1207) of the total anopheline population and the average man-biting rate was 10.90, 24.88 and 8.71 respectively. The sporozoite positive rate, the human blood index and the daily survival rate were 0.54% (3/554), 1.0 and 0.803 respectively. The parasitaemia rate, the rate of gametocyte carriers, and the rate of persons with malaria history within 1-2 months were 45.5% (10/22), 13.6% (3/22) and 50.0% (11/22), respectively. On average, the entomological inoculation rate A, B and C calculated by three methods were 0.084, 0.665 and 0.215, respectively, indicating that the workers might get malaria infection if they stayed at the camp for 1.5-11.9 days. An analysis of the malaria onset time of the patients suggested that the time calculated from the inoculation rate A was closer to the real situation than those calculated from the inoculation rate B or C. The prevalence trend of malaria could be predicted through the monitoring of the entomological inoculation rate.


The adenovirus E1A proteins induce apoptosis, which is inhibited by the E1B 19-kDa and Bcl-2 proteins.

Cooperation between the adenovirus E1A and E1B oncogenes is required for transformation of primary quiescent rodent cells. Although expression of E1A alone will stimulate cell proliferation sufficient to initiate transformed focus formation, proliferation fails to be sustained and foci degenerate. Coexpression of either the 19-kDa or 55-kDa E1B oncoproteins with E1A permits high-frequency transformation by overcoming this cytotoxic response. Without E1B 19-kDa protein expression, however, transformants remain susceptible to induction of cell death. Rapid loss of viability is coincident with nucleolytic cleavage of DNA in intranucleosomal regions and chromatin condensation, hallmarks of programmed cell death (apoptosis). Furthermore, overexpression of a known suppressor of apoptosis, the Bcl-2 protooncogene, can rescue E1A-induced focus degeneration. Thus E1A-dependent stimulation of cell proliferation is accompanied by apoptosis and thereby insufficient to singly induce transformation. High-frequency transformation requires a second function encoded by the E1B 19-kDa protein to block apoptosis.


[Changes in auriculoventricular conduction due to the effect of ethanol].

Transcoronary ablation of atrioventricular conduction by dehydrated alcohol was attempted in one patient with refractory ectopic atrial tachycardia. Ethanol (1.5 ml) was delivered after selective catheterization of the atrioventricular nodal artery in a patient in whom the artery could be identified by cineangiography. The mean creatine kinase (MB fraction) at four hour to six hour after ablation was 40 U. No electrocardiographic QRS changes was seen. The procedure was successful. The patient is asymptomatic 3 months after procedure. Transcoronary alcohol ablation of atrioventricular conduction should be considered in patients in whom electrical techniques have been unsuccessful.


Intracranial arterial aneurysm due to birth trauma. Case report.

The authors present what is believed to be the first description of an intracranial arterial aneurysm attributable to birth trauma. A male neonate, the product of a precipitious, instrumented, footling breech delivery, exhibited seizures at the age of 18 hours. A computerized tomography scan of the head showed hemorrhage along the tentorium with a globular component at the incisura. Transfontanel Doppler ultrasound examination detected pulsatile arterial flow within the globular mass. Cerebral angiography demonstrated a 1.5-cm saccular aneurysm arising from a small distal branch of the superior cerebellar artery. The pathogenesis of aneurysms in children is obscure and controversial. Birth trauma may be responsible for some pediatric aneurysms that are currently classified as idiopathic or congenital, particularly aneurysms in the region of the tentorial incisura.


Survival response of a human glioma cell line to hyperthermia associated with rhein.

The effect of association of hyperthermia with the anti-inflammatory drug rhein (RH), 4,5-dihydroxyanthraquinone-2-carboxylic acid, on the clonogenic activity of human glioma cells has been examined. RH inhibits neoplastic growth mainly through an ATP depletion, but thermal cell killing is not mediated by the drug-induced changes in the energy status of the cell. The analysis of the interaction between RH and hyperthermia, performed with the isobolar method, demonstrates an additivity of the response so that the effectiveness of the combined treatment is the result of two independent effects. Although the effect of this combination is purely additive, RH allows us to achieve a pre-established cell killing with exposure times at 42 degrees C, which is generally accepted to be clinically achievable. RH might, therefore, be employed to reduce the side effects of hyperthermia without impairing its therapeutic effectiveness.


Early-retirement incentive programs for medical school faculty.

The Association of American Medical Colleges surveyed the principal business officers of all 126 accredited U.S. medical schools in late 1991 in order to learn about their retirement benefit programs for faculty and whether early-retirement incentive programs were being used. A total of 115 of the schools provided usable responses, which the author reports for all schools, public schools, and private schools. For all schools, defined-contribution plans (based on employer's and employee's contributions plus investment earnings) were the preferred type of retirement benefit program (77%, or 89, of the responding schools). Defined-benefit plans (based on a formula that uses variables of age at retirement, years of service, and salary) were available at 37% (43) of the schools. Early-retirement incentive programs had been used by 70% of the responding schools in the five-year period 1987-1991. Sixteen schools provided descriptions of their formal early-retirement programs, which are summarized. The author observes that, although nearly three-fourths of the responding schools are familiar with the use of the incentive programs, these programs have resulted in few actual early retirements. He discusses why this may be true and compares the pros and cons of formal and ad hoc programs. He concludes that no single program can be considered best; each institution must work with its faculty to design programs to meet institutional goals and faculty interests.


The crisis in osteopathic medicine.

During the last 30 years the osteopathic profession has undergone a remarkable transformation from osteopathy, characterized by manipulative therapy, to osteopathic medicine, characterized by full-service health care, and in the process it has won acceptance from the government, the military, and physicians. These changes in status have resulted in new problems for the profession, because D.O. graduates are turning increasingly toward M.D. programs for residency training, and osteopathic medicine's primary care orientation is being replaced by an emphasis on specialty training. The authors advocate that osteopathic medicine return to its original mission of primary care, abandon specialty training or restrict it to those who have completed primary care residencies, abolish its separate-but-equal posture, and establish lines of communication with allopathic medicine and the American Medical Association to facilitate the development of a rational national policy for primary care that considers the potential osteopathy has to offer in meeting the nation's primary care needs.


[Characteristics of tobacco smoking in schools in Andorra].

1600 schoolchildren aged 13 to 18 answered an anonimus, self administered questionnaire, in a cross sectional study to estimate the prevalence of cigarette smoking in the high grades schools in Andorra. 46.6% answered they did smoke cigarettes, either daily (11.2%) or occasionally (35.4%). Ten per cent of actual smokers did already smoke at age 10, and 50% at age 13. More girls (48.8%) than boys (44.4%) smoked (p less than 0.05) but boys smoked a greater number of cigarettes (p less than 0.001). Ninety five percent smoked Virginia tobacco, and little more than 50% used filter tipped cigarettes. Two thirds of smokers inhaled the smoke of cigarettes; this was more common among daily smokers. Again two thirds of smokers answered they would be prepared to quit smoking. 31% of those who had tried smoking said they believed they would smoke in the future, while only 5.6% of those that never smoked previously said so (p less than 0.001). Actual smokers answered they believed that they would not smoke in the future much less often than non smokers. Parents let boys smoke more than girls when the children started doing so, particularly before age thirteen and after age fifteen. These are the first available data about the community studied describing some features of its cigarette smoking habit. Their knowledge may well help to plan disease protection and health promotion developments addressed to youngsters in Andorra.


Relationship of medical students' admission interview scores to their dean's letter ratings.

The authors examined the relationship between the admission interview scores for 62 students in the 1986 entering class at Dartmouth Medical School and the students' dean's letter ratings given four years later; they found the relationship to be significant (V = .372, p = .014) and the interview scores to be better independent predictors of the ratings than were total Medical College Admission Test scores or science grade-point averages. Among the 17 students receiving "strong" admission interview scores, 53% received dean's letter ratings in the top one-third and 47% received ratings in the lower two-thirds. Of those 34 who received "medium" interview scores, 68% received ratings in the lower two-thirds; all 11 students who received "weak" interview scores received ratings in the lower two-thirds. The authors suggest (1) that admission interview scores help schools to identify more clearly those applicants most likely to become strong, competitive performers in residency and (2) that the significant relationship between interview scores and dean's letter ratings indicates a need to discover what qualities the interview actually measures and to consider the methods by which interviewers are trained, rather than to forsake the interview.


The role of grades in gaining admission to highly selective medical schools.

The authors examine the role of grades in the admission decisions at a group of 19 highly selective medical schools by analyzing over 8,000 applications from Cornell University students for the entering medical school classes of 1982 through 1989. The results illustrate the great influence of the grade-point average (GPA) on the admission decision. Between the GPA levels of 3.0 and 3.8, the chance of acceptance increased by a factor of about two for each increment of .2 in the GPA. For a subset of the nine most selective of the 19 institutions, the chance of acceptance increased by a factor of five for each increment of .2. At these nine schools, of 1,157 applications with a GPA of less than 3.4, only four were approved. The authors suggest the evidence indicates that students often receive encouragement to continue the application process even though the chances of eventual acceptance are negligible.


Multiple authorship in two English-language journals in radiation oncology.

Multiple authorship is the listing of more than one person as author of an article in the scholarly literature. Editors, researchers, and others in science publishing have raised concerns about the increasing number of authors being listed per article, the practice of "honorary authorship" (listing as an author someone who made little or no contribution to the work being reported), and the danger of the dilution of responsibility when many authors are involved. The authors studied multiauthorship in the two most popular English-language journals on radiation oncology, examining 1,908 papers and letters published in the International Journal of Radiation Oncology, Biology, and Physics (IJROBP) and Radiotherapy and Oncology (RO) from 1983 through 1987. There was no increase in the number of authors per article during this period, when the median number for IJROBP was four and that for RO was three. The number of authors varied by type of article, by country (France had the largest median number, six for IJROBP and five for RO), and by the authors' institution. The first author's gender was unrelated to the number of subsequent authors for an article. The proportion of men first authors varied widely between countries and institutions. Possible explanations for these variations include the multidisciplinary nature and complexity of some forms of research, institutional policies concerning the use of authorship as a commodity of exchange, and social-cultural factors.


Consistency between peer reviewers for a clinical specialty journal.

To analyze the consistency between independent peer reviewers in evaluating and ranking unsolicited articles, the authors used paired reviews of 422 unsolicited submissions to the Journal of Clinical Anesthesia from the end of 1988 through 1991. (The editors of this journal base their publication decisions, to a substantial degree, on congruence of their reviewers' recommendations). The reviewers were chosen for their interest in reviewing and areas of expertise. Their recommendations were ranged along a continuum of four categories: (1) accept outright, (2) accept with revision, (3) reject in present form (article could be revised and submitted again as a new submission), and (4) reject outright. The pairs of peer reviewers were consonant for 169 papers (40%), differed by one category for 168 papers (40%), differed by two categories for 73 papers (17%), and differed by three categories for 12 papers (3%). Thus, most articles' reviews were in consonance or close to it; articles reviewed by two members of the editorial board, however, were significantly less likely to be consonant (32%) than were those reviewed by two nonmembers (44%, chi-square, p = .027).


Comparing the accuracies of entire-group and subgroup models to predict NBME-I scores for medical school applicants.

To address the question of whether prediction models for subgroups of medical school applicants lead to more accurate predictions of performance than does one model for an entire group of applicants, the authors used data from two groups of students at Jefferson Medical College: 415 students who entered Jefferson in 1985 and 1986, and 396 who entered in 1987 and 1988. Both groups were divided into two subgroups by gender and two subgroups by age. Data from the first group were used to develop prediction models based on the entire group and on its four subgroups. The predictors were undergraduate grade-point averages and Medical College Admission Test scores; the criterion measures were scores on the National Board of Medical Examiners Part I examinations. The prediction models were then applied to data from the second group and its four subgroups: differences in the validity coefficients (.40 to .56) and residual scores (7.2 to 17.9) were not considered to be of practical importance. Hence, the authors suggest that gender and age do not contribute to a prediction bias and that an entire-group prediction model can be used without serious concern for over-or underestimating the predicted scores.


Attitudes of part-time community internal medicine faculty about their teaching.

The authors sent a six-item questionnaire regarding attitudes about teaching to 130 part-time community internal medicine faculty at the University of Illinois College of Medicine at Rockford in August 1991; of the 90 (69%) who responded, 53 were salaried and 37 nonsalaried. Substantial numbers of the salaried faculty responded (1) that teaching is important for their career development (25, 48%), compared with nine (22%) of the nonsalaried faculty, and (2) that they expected to increase their commitments to the medical school (50, 75%), compared with 24 (65%) of the nonsalaried faculty. Of all the faculty, fewer than the authors expected--22 (24%)--felt that their teaching interfered with their clinical practices. As expected, most (76, 84%) responded that salary was necessary. The authors suggest that their results may be helpful to other medical schools, because with the setting of medical education changing from the hospital to the community, the importance of part-time faculty is increasing.


Occurrence, removal and seasonal variation of "thermophilic" campylobacters in a sewage treatment plant in Italy.

Monitoring of "thermophilic" campylobacters in a sewage treatment plant in Bologna (Italy) has shown that incoming sewage contained a most probable number of 1630 campylobacters/100 ml. The secondary treatment in activated sludge tanks reduced 98.61% of campylobacters, 95.32% of fecal coliforms, 96.46% of fecal streptococci, 93.36% of salmonellas and 93.01% and 88.29% of BOD5 and COD respectively. Subsequent tertiary treatment with 3 ppm of chlorine dioxide for 15 min reduced 100% of campylobacters and salmonellas. Significant correlation coefficients were found in incoming sewage between campylobacters and salmonellas (p < 0.01) and between campylobacters and fecal coliforms (p < 0.02). Campylobacter jejuni and Campylobacter coli constituted 51.3% and 48.7% respectively of the 80 strains isolated. In incoming sewage 66% of the strains isolated were found to be Campylobacter jejuni whereas Campylobacter coli strains were prevalent in activated sludge effluent (69.7%). The greatest frequency of isolation and the higher counts were obtained during the Spring to Summer period with distinct peaks in May, June and July. This seasonability is probably due to the seasonal variation of campylobacter infections in man and animals.


[Development and monitoring of the hygienic water quality at bathing facilities in northwest Germany from 1989 to 1991].

Since the introduction and strict application of EC guidelines on the monitoring of bathing waters began in Lower Saxony in 1989, it has been possible for the first time to reach a comprehensive evaluation of the water quality on the North Sea coast and in the rivers and lakes of this state. The 7648 samples which were analysed in this period produced the most favourable results on the East Friesian Islands, followed by the vast majority of the mainland bathing resorts and some lakes. On the lower stretches of the River Weser and in a few lakes levels were registered at times which exceeded the limits to such an extent that bathing was impossible. In 1991 extreme germination of total coliform bacteria was observed for the first time, presumably due to eutrophic conditions in combination with high water temperatures.


[Comparative study of the detection of E. coli after time in seawater with partially modified standard media].

Fecal coliform bacteria (E. coli) are the most important parameter when monitoring the hygienic quality of bathing water according to EC guidelines. Among other things the number of E. coli is clearly dependent on the length of exposure of the bacteria to marine water as well as the media used to establish the number. In a seven-day salt water stress experiment the best rate of recultivation was achieved on average with DEV lactose peptone broth. The Brila-MUG medium produced a slightly lower rate of recultivation and the fluorocult-lauryl-sulfate-broth the lowest rate of recultivation. After a shorter exposure of bacteria to marine water conditions (up to 24 h) the DEV-lactose-broth produced slightly lower rates of recultivation. An alteration of the standard components of the media did not lead to an improvement in the rate of recultivation.


Faecal micro-organisms on the hands of carriers: Escherichia coli as model for Salmonella.

To evaluate the public health hazard caused by Salmonella carriers as food handlers, a study was carried out to gather more quantitative data about faecal contamination of hands after stools. Faecal E. coli was used as a model bacterium for Salmonella. In total 92 subjects cooperated in this study. The hand was sampled before toilet use, and also after stools, with or without washing of the hands. Besides E. coli the number of Enterobacteriaceae was also determined. It appeared that hands may be contaminated with Enterobacteriaceae, regardless of toilet use, for a well before as after stools about 60% of the sampled hands carried a detectable number of Enterobacteriaceae. That is why the presence of Enterobacteriaceae on hands is not a good indicator for toilet hygiene. In 4% of the samples before stools and in 25% of the samples taken after stools E. coli could be detected (> 20 CFU/sample). The average 10log CFU of E. coli in the positive samples taken before and after stools were about the same: 2.30 per sample. Hand washing after stools reduced the numbers of Enterobacteriaceae and E. coli on the hands. It was concluded that symptomless Salmonella excretors in the period starting two weeks after infection form only a low risk in carrying over Salmonella by their hands to food. Especially if normal hygiene is practiced like washing hands after stools, the number of contaminated hands will be very low and furthermore the number of faecal micro-organisms will be very small.(ABSTRACT TRUNCATED AT 250 WORDS)


[The determination of the discrepancy between the mathematically ascertained and experimentally provable efficiency of UV facilities for water disinfection].

Using three UV-plants of different technical designs for water disinfection, we studied the conformity between experimental germ reduction using standard test organisms and calculated UV-doses under various water flow conditions. Taking into consideration the style of construction of the UV-plants, the irradiation area and the layer thickness were used as constant parameters for dose calculations. This was also employed for the irradiation intensity, since the experiments were performed for a relatively short period compared of the life span of the UV-irradiators. Both exposure time and water transmission were employed as variable parameters in the dose calculations and experimental procedures respectively. The calculated UV-dose and experimentally obtained germ reduction values were comparatively the same for two of the three UV-plants studied. However, no correlation was observed between the reduction of E. coli and the corresponding calculated UV-dose values. Therefore, the calculated UV-dose values for any given UV-plant should be considered to be relative and by no means absolute values. We are of the opinion that within a certain range of water flow rate and transmission, antimicrobial effectiveness of different UV-plants should be demonstrated independent of dose values, technical and other construction characteristics. The applicability of the UV-plants studied is discussed.


[RoTrac capillary pore membranes for laboratory filtration. II. Bacteria-free filtration].

Because of their special characteristics Capillary pore membranes (CPM) are now applied in several branches of separation techniques and analytics. Besides applications in particle analytics and microfiltration of different media capillary pore membranes can be used in microorganism separation. It was shown that RoTrac CPM can be used for bacteria free (or so called sterile) filtration. Acceptable fluxes were reached in separation of Pseudomonas diminuta (test species ATCC 19146). Membranes with pore diameters of 0.2 micron and smaller always assure a bacteria free filtrate even for a very high bacteria count of about 10(7)-10(8) bacteria/ml. In filtration of Mycoplasma arginini no sterile filtrate was obtained for a pore diameter of 0.08 micron and a high bacteria count of 3 * 10(7) bacteria/ml. The bacteria rejection by a factor of 10(5) was however remarkable. Only for 0.05 and 0.08 micron with reduced bacteria load the filtrate was bacteria free.


[Case study of a Legionella epidemic in a rehabilitation clinic].

A series of nosocomial Legionella infections in a rehabilitation center is reported. In a three months period a total of 10 pneumonias with 3 deaths occurred (8 patients, 1 companion, 1 staff member). Serologic analysis proved additional Legionella infections within the nursing staff. The warm-water system was proved to be the source of infection by isolating Legionella pneumophila serogroup 1 subtype Pontiac both in warm-water and patients samples. The air conditioning system could not be ruled out as another (secondary) route of exposure because of shortcomings in construction. Conclusions about prevention and the course of the disease are discussed and standards for warm-water and air conditioning systems are proposed.