Multifocal motor neuropathy human sera block distal motor nerve conduction in mice

Multifocal motor neuropathy (MMN) is associated with serum autoantibodies to gangliosides, but their pathogenic role is uncertain. We have used a novel approach to study the effects of serum and plasma from 8 patients with this syndrome, 6 of whom were anti-GM1 positive. The nerve stimulus required to evoke muscle contraction and endplate potentials (EPPs) was measured in the mouse phrenic nerve-diaphragm preparation during 4 to 6 hours of direct application (plasma at 1:1 or serum 1:2 dilution) and following intraperitoneal injection of plasma (1 ml/day) for 1 to 5 days ("passive transfer"). Direct application of MMN serum or plasma produced a progressive increase in stimulus threshold, followed by complete block of nerve-evoked muscle contraction in 3 cases, and an associated decline to about 50% of the EPP amplitude followed by sudden loss of EPPs. These effects were complement independent. Even with complete block of nerve-evoked EPPs, miniature EPP (MEPP) frequency could be increased by raising external K+ to depolarize the nerve terminal directly. Passive transfer of 1 ml of MMN plasma (n = 5) for 3 days caused similar but less marked changes. These results demonstrate that serum factors in MMN can block nerve conduction at distal motor nerves.

A mutant pertussis toxin molecule that lacks ADP-ribosyltransferase activity, PT-9K/129G, is an effective mucosal adjuvant for intranasally delivered proteins

We examined the capacity of a genetically detoxified derivative of pertussis toxin (PTX), PT-9K/129G, to act as a mucosal adjuvant for an intranasally (i.n.) administered tetanus vaccine. Groups of mice were immunized i.n. with the nontoxic C-terminal 50-kDa portion of tetanus toxin (fragment C [Frg C]) either alone or mixed with PT-9K/129G, PTX, or cholera toxin (CT) or were immunized subcutaneously (s.c.) with an equivalent amount of Frg C adsorbed to alhydrogel. In response to a single immunization, mice receiving Frg C plus PT-9K/129G or CT i.n. and parenterally immunized mice developed high-titer (> 20,000) anti-Frg C antibodies, whereas mice immunized i.n. with Frg C plus PTX or with Frg C alone seroconverted only after being boosted. The serum anti-Frg C response was dominated by immunoglobulin G1 (IgG1) in mice immunized with Frg C plus PT-9K/129G, with Frg C plus PTX, or s.c. In contrast, IgG1, IgG2a, and IgG2b contributed almost equally to the Frg C response when CT was the adjuvant. Anti-Frg C IgE was detected only in the sera of mice immunized i.n. with Frg C plus PTX and immunized s.c. with Frg C plus alhydrogel. High levels of IgA antibodies were present in nasal lavage fluid from mice immunized i.n. with Frg C plus PT-9K/129G, PTX, or CT but not in that from mice given Frg C alone i.n. or parenterally. The mucosal adjuvanticity of PT-9K/129G was manifested in inbred as well as outbred mice. A single i.n. dose of Frg C plus either PT-9K/129G or PTX (with high specific activity) was sufficient to protect all immunized mice from tetanus toxin challenge, in contrast to the case for mice that received Frg C alone i.n. We conclude that the pertussis toxin analog PT-9K/129G, which is devoid of ADP-ribosyltransferase activity, is a potent mucosal adjuvant for vaccines delivered via the respiratory tract.

Hypersensitivity pneumonitis in a raptor handler and a wild bird fancier

BACKGROUND

Hypersensitivity pneumonitis has been associated with a variety of antigens in various settings. We have recently encountered one case of hypersensitivity pneumonitis from owl droppings and another case from a wild Moluccan cockatoo.

OBJECTIVE

It is important to alert physicians to the possibility of hypersensitivity pneumonitis when dealing with wildlife workers and wild bird fanciers.

METHOD

A report of two cases with progress and response to therapy.

RESULTS

Clinical and serologic information are of value in the diagnosis of hypersensitivity pneumonitis due to birds and avoidance is the optimal approach.

CONCLUSION

There are many raptor handlers and wild bird fanciers across the United States and the world. Given the incidence of hypersensitivity pneumonitis in pigeon breeders, this may herald a new variant of allergic disease among wildlife workers and wild bird fanciers.

Reversible and selective inhibitors of monoamine oxidase A in mental and other disorders

The clinically tested reversible inhibitors of monoamine oxidase A (RIMAs) include brofaromine, moclobemide and toloxatone. Moclobemide has shown unequivocal antidepressant activity against serious depressive illness in 4 placebo-controlled double-blind trials. It has been compared with amitriptyline, imipramine, clomipramine, desipramine, maprotiline, fluoxetine, fluvoxamine, tranylcypromine, toloxatone, mianserin and amineptine in the treatment of depressive disorders. Meta-analysis showed convincing evidence of moclobemide efficacy, comparable with the most potent antidepressants available. The efficacy of moclobemide has been demonstrated in psychotic and non-psychotic depression, in depression with and without melancholia, in endogenous depression (both unipolar and bipolar), in retarded depression and in agitated depression. The efficacy of moclobemide, allied to the unusually benign side effect profile, has led to exploration of its use in other disorders. Two small studies have given encouraging results in the treatment of attention-deficit hyperactivity disorder. Large placebo-controlled studies have shown the activity of moclobemide in the depression that accompanies dementia (such as senile dementia of Alzheimer type). The results also suggested that, in this patient population, cognitive ability improved in parallel. Social phobia has also been shown to improve on treatment with either moclobemide or brofaromine. Clinical trials are in progress on the effect of moclobemide in chronic fatigue syndrome. Moreover, there are encouraging results with the use of brofaromine and moclobemide in panic disorder. Other disorders in which treatment with RIMA is of interest include agoraphobia, bulimia, borderline personality disorder, post-traumatic stress disorder, compulsive hair pulling (trichotillomania), dysmorphophobia, kleptomania as well as various anxiety syndromes.

Disordered water homeostasis in schizophrenia and cerebral ventricular size

BACKGROUND

A possible association between disordered water homeostasis and cerebral ventricular size in patients with schizophrenia was investigated.

METHOD

In a cross-sectional study of hospitalised patients, cerebral ventricular size was measured in 16 schizophrenic patients with disordered water homeostasis and 16 matched schizophrenic controls by magnetic resonance imaging.

RESULTS

Ventricle to brain ratio, third ventricular index, bicaudate index and bifrontal index tended to be greater in those with schizophrenia with disordered water homeostasis, although differences were significant only for the bifrontal index (P < 0.05). Strong negative correlations were found between ventricular size and performance on neuropsychological testing in the disordered water homeostasis group.

CONCLUSION

These results provide evidence for an association between structural brain abnormality and disordered water homeostasis in a subset of schizophrenic patients.

The nutritional status and clinical course of acute admissions to a geriatric unit

Undernutrition of long-stay hospital patients and those in surgical units is well documented. This study was designed to determine the extent of the problem in elderly people admitted to hospital with acute medical problems and to assess the relationship between nutritional status and course of hospital stay. Sixty-nine patients underwent a nutritional assessment on admission and at intervals throughout their hospital stay and episodes of sepsis were documented. Severely malnourished patients were identified using body mass index, BMI (22%) and corrected arm muscle area, CAMA (26%). Episodes of sepsis occurred significantly more often in the severely undernourished group (p < 0.04). The median length of stay of the group was 16 days (range 2-113): during this time there was no significant change in markers of nutritional status apart from actual muscle circumference (AMC), which showed a reduction in measurement between admission and discharge which was statistically significant (p < 0.0003). This study indicated that severe malnutrition is common in elderly medical admissions, and that it is associated with an increased risk of sepsis. Additional nutritional depletion may occur during hospital stay, and is not easily recognized unless anthropometry is undertaken.

Heart transplantation in the United Kingdom: who waits longest and why

BACKGROUND

This study aims to identify characteristics that increase the chance of death of potential cardiac transplant recipients before donor organs become available.

METHODS

Between June 1, 1988, and May 31, 1993, 332 patients were accepted for heart transplantation; 235 underwent surgery. Ninety-seven patients had not received transplants; of these, 71 died, 13 were transferred to other lists, and 13 were awaiting organs at the close of the study. Median waiting time for those patients who received organs was 109 days, whereas patients who did not receive organs spent a median of 94 days on the list. Recipients are matched to donor organs according to blood group, size (height), and, recently, preoperative transpulmonary pressure gradient. Recently cytomegalovirus antibody mismatches (positive donor to negative recipient) have been avoided where possible. These factors, together with age, gender, underlying diagnosis, previous heart surgery, and Toxoplasma antibody status were studied to assess their influence on waiting time and survival.

RESULTS

No characteristics were found significantly to influence survival after acceptance, so that the chance of death while the patient was waiting for heart transplantation is mainly affected by the severity of disease and the length of time a patient waits. In multivariate analyses the following were independently significantly associated with shorter waiting times: small patients (< 1.7 m tall; p = 0.005), patients with blood types B and AB (p = 0.003), and patients with cardiomyopathy (p < 0.001).

CONCLUSIONS

These results can be used by cardiologists to help assess the time at which a patient should be referred for transplantation.

The development of oral vaccines against parasitic diseases utilizing live attenuated Salmonella

Genetically defined, live attenuated Salmonella vaccines are proving useful both as oral vaccines against salmonellosis and for the development of multivalent vaccines based on the expression of heterologous antigens in such strains. Several candidate attenuated S. typhi strains are at present being evaluated as new single dose oral typhoid vaccines in human volunteers. The emergence of such a vaccine will facilitate the development of multivalent vaccines for humans. Many antigens from different infectious organisms have been expressed in attenuated Salmonella. A focus of this work has been on developing vaccines against parasitic diseases. This review will summarize the efforts that have been made in this area.

Mutants of Escherichia coli heat-labile toxin lacking ADP-ribosyltransferase activity act as nontoxic, mucosal adjuvants

A nontoxic mutant (LTK7) of the Escherichia coli heat-labile enterotoxin (LT) lacking ADP-ribosylating activity but retaining holotoxin formation was constructed. By using site-directed mutagenesis, the arginine at position 7 of the A subunit was replaced with lysine. This molecule, which was nontoxic in several assays, was able to bind to eukaryotic cells and acted as a mucosal adjuvant for co-administered proteins; BALB/c mice immunized intranasally with LTK7 and ovalbumin developed high levels of serum and local antibodies to ovalbumin and toxin. In addition, mice immunized intranasally with fragment C of tetanus toxin and LTK7 were protected against lethal challenge with tetanus toxin. Thus nontoxic mutants of heat-labile toxin can act as effective intranasal mucosal adjuvants.

Allergic bronchopulmonary aspergillosis: serologic update for 1995

Allergic bronchopulmonary aspergillosis (ABPA) is a complex disease occurring in 1-2% of patients with asthma involving hypersensitivity to Aspergillus species. The diagnosis is made correlating clinical history and supporting serologic tests. Over many years various serologic tests have been used to both diagnose and follow disease activity. Initial serology from patients with all four positive tests (total serum IgE, IgE and IgG antibody indices, serum precipitins to Aspergillus fumigatus) were compared with the patients' most recent serology. The total serum IgE, IgE antibody index and serum precipitins had the most initial positive tests which stayed positive throughout treatment. The IgG antibody index was the most inconsistent. There were no significant differences between all four tests. We concluded that all four serologic tests are important in the diagnosis of ABPA.

Is puerperal psychosis bipolar mood disorder?: a phenomenological comparison

The most widely held current view on puerperal psychosis (PP) is that it is a mood disorder; some researchers have even suggested that it may be linked to bipolar mood disorder (BMD). To compare the phenomena of PP and BMD, 20 patients with PP were compared with 20 concurrent age-matched women with BMD, using the Structured Clinical Interview for DSM-III-R (SCID). To exclude patients with possible unipolar disorder, subjects with depression were not considered for inclusion in the study. A significantly greater proportion of the PP group experienced delusions of control, auditory hallucinations, blunted affect, and emotional turmoil. Seven (35%) of the PP patients fulfilled DSM-III-R criteria for BMD. These results do not support the hypothesis that PP and BMD are the same illness. Further research is necessary to explore the possibility of a link between these two conditions.

Autoantibodies, neurotoxins and the nervous system

Myasthenia gravis, the Lambert-Eaton myasthenic syndrome, and acquired neuromyotonia are three disorders of the neuromuscular junction or motor nerve that are caused by autoantibodies to ion channel proteins: acetylcholine receptors, voltage-gated calcium channels and voltage-gated potassium channels, respectively. The antibody titres can be measured using the relevant 125I-neurotoxins to label the extracted channels. Other disorders of the peripheral motor nerve are associated with antibodies to gangliosides. Sera with raised levels of anti-ganglioside antibodies have direct effects on the function of the distal motor nerve and motor nerve terminal. These conditions can be improved by therapies designed to reduce circulating antibodies. Antibodies that bind to neuronal surface antigens are proving to be of great clinical importance and interest in neurological disorders.

Expression of the Bordetella pertussis P.69 pertactin adhesin in Escherichia coli: fate of the carboxy-terminal domain

The mature pertactin protein (P.69) of Bordetella pertussis can be isolated from the bacterial cell surface as a polypeptide with an apparent molecular mass of 69,000 Da as determined by sodium dodecyl sulphate gel electrophoresis. However the open reading frame of prn, the pertactin gene, encodes a polypeptide with a predicted molecular mass of 93,478 Da, referred to as P.93. Expression of the prn gene in Escherichia coli leads to the synthesis of the full-length P.93 polypeptide, which is rapidly processed to the mature P.69 protein located at the cell surface. The P.93 precursor polypeptide is processed at both termini. A 34 amino acid long signal sequence is removed from the amino-terminus and a polypeptide sequence of about 30,000 Da (P.30) is cleaved from the carboxy-terminus. Deletion of the 3' region of prn, encoding P.30, results in the expression of an intracellular form of P.69. Antiserum which recognizes P.30 was raised using synthetic peptides based on the primary amino acid sequence of the region. This anti-P.30 serum was used in a Western blot analysis of fractionated cells of B. pertussis and E. coli harbouring the intact prn gene. The P.30 polypeptide was readily detected in outer membrane fractions prepared from both of these bacterial species, although it could not be shown to be exposed at the cell surface.

Dendritic cells from HIV-1 infected individuals show reduced capacity to stimulate autologous T-cell proliferation

Dendritic cells (DC) exposed for a short period of time (1 day) in vitro to HIV infection caused stimulation of autologous T-cells, but those exposed for a longer period (3 days) before addition to T-cells stimulate little or no proliferation [1]. Since a proportion of DC from patients who are HIV-1 seropositive is infected with HIV-1 [2] we used the same culture system to test the level of ongoing stimulation of autologous T-cells by DC. The DC from patients with HIV-1 infection showed no enhanced stimulation of autologous T-cells; they produced significantly lower levels of proliferation than those induced by DC from normal controls or from high risk seronegative individuals. However, DC stimulated production of antibodies to gp120 and p24 in cultures containing autologous B plus T-cell in the absence of any added exogenous antigens as previously described [3]. DC in asymptomatic individuals thus appear to be fuelling antibody production but not T-cell proliferation. The results suggest that a failure by DC to stimulate T-cell proliferation either to HIV-1 or to other environmental antigens may be involved in the failure of cell-mediated responses in HIV infection.

[Depressive states and chronic asthenic syndromes in general practice]

It has been shown in Great Britain that general practitioners fail to recognize as many as 50% of the cases of depressive illness that present to them. The diagnosis is missed particularly when it is the physical type of symptom, such as asthenia, that is prominent. The Royal College of Psychiatrists, in association with the Royal College of General Practitioners, has launched the "Defeat Depression" campaign which includes amongst its aims the intention to provide up-to-date educational materials to family doctors on the recognition and treatment of depression. We have held two consensus meetings jointly with psychiatrists and primary care physicians and the results have been published in the British Medical Journal (2). One of our key recommendations is that, when medication is used to treat depressive illness in general practice, the antidepressants should be continued for six months after full remission has taken place. At present patients in general practice take their drugs for a total of three or four weeks. One of the reasons for patients abandoning their medication prematurely has been revealed by surveys that we have carried out on the general public. The lay person has little confidence in the efficacy of antidepressants and, perhaps more importantly, believes that they are addictive. It is therefore no surprise, then, that patients are keen to stop their antidepressants before they become dependent on them.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparative studies of UV-induced DNA cleavage by analogues of iodoHoechst 33258

Following the earlier demonstration that iodo-Hoechst 33258 sensitizes DNA and cells to UVA, presumably mediated by formation of a carbon-centred radical on the ligand upon dehalogenation, three isomeric analogues of iodo-Hoechst 33258 have now been studied. The isomers differ in the location of the iodine atom in the phenyl ring of the ligand, relative to the site of attachment of the bibenzimidazole moiety, and are accordingly denoted ortho-, meta- and para-iodoHoechst. Comparison of the ligands with respect to induction of DNA ssb in pBR322 DNA revealed a wide range of activity; (D37's vary by a factor of 37), decreasing in the order: ortho- > meta- and para- > iodoHoechst 33258. Preliminary dehalogenation studies suggest that the higher activity of the ortho isomer results more from increased cross-section for dehalogenation than from increased efficiency of strand breakage per dehalogenation event. However, the chemistry of strand breakage by the ortho-isomer is distinctive, and tentatively assigned to initial attack at the 1'-deoxyribosyl carbon; the other two isomers, like iodo-Hoechst 33258, attack the 5'-carbon. The results are discussed in terms of the spectrum of DNA strand breakage chemistry associated with ionizing radiation, and the potential of DNA strand breaking agents such as the iodoHoechst compounds to study the chemical and biological consequences of the different subclasses of initial DNA damage.

Androgen suppressive effect of GnRH agonist in ovarian hyperthecosis and virilizing tumours

OBJECTIVE

Recent studies have suggested that androgen secretion by ovarian virilizing tumours may be gonadotrophin dependent. The aim of this study was to investigate the suppressive effect of GnRH agonist administration on androgen secretion in women with such tumours.

DESIGN AND PATIENTS

A single i.m. injection of D-Trp-6-GnRH (GnRHa), 3.75 mg, was given to five unrelated patients referred for clinical symptoms of virilization with plasma testosterone (T) levels greater than 7 nmol/l but with normal dehydroepiandrosterone sulphate (DHEAS) levels. Diagnoses of adrenal tumour or a non-classical 21-hydroxylase deficiency were screened for by the dexamethasone suppression test, ACTH stimulation test and adrenal CT scanning, and were ruled out in all patients. The one premenopausal patient received cyproterone acetate in a dose of 50 mg twice daily for 3 weeks, starting 1 week before GnRHa administration.

MEASUREMENT

Testosterone, androstenedione (A), DHEAS, 17-hydroxyprogesterone (OHP), LH and FSH plasma concentrations were measured by radioimmunoassay of blood samples taken before and 3 weeks after GnRHa.

RESULTS

In each patient, GnRHa suppressed gonadotrophin levels and reduced T and A to the range for normal control women. With these results, and because accurate localization of an ovarian androgen secreting tumour could not be achieved by pelvic ultrasonography and CT scanning, exploratory laparotomy was undertaken. A Sertoli-Leydig cell tumour was found in the premenopausal patient, and granulosa cell tumour, hilus cell tumour and two hyperthecoses in the four post-menopausal patients. After bilateral ovariectomy and hysterectomy in the post-menopausal woman and after unilateral ovariectomy in the premenopausal women, androgen levels were normalized.

CONCLUSIONS

In virilized women, the findings of increased serum testosterone with normal gonadotrophin levels and GnRHa suppression of gonadotrophins leading to normalization of testosterone levels, suggest that various ovarian androgen-secreting tumours, as well as hyperthecosis, are not autonomous but apparently depend upon continuous gonadotrophin stimulation.

Characterization of defined ompR mutants of Salmonella typhi: ompR is involved in the regulation of Vi polysaccharide expression

The ompB operon, comprising the ompR and envZ genes, was cloned from a Salmonella typhi Ty2 cosmid bank and characterized by DNA sequence analysis. The S. typhi ompR and envZ genes contained open reading frames encoding proteins of 240 and 451 amino acids, respectively. Comparison with the Salmonella typhimurium OmpB protein sequences revealed 99.5% homology. The DNA sequence data were used to identify appropriate restriction sites for generating a defined deletion of 517 bp within the open reading frame of the ompR gene. This deletion was introduced by homologous recombination into the chromosomes of two S. typhi strains which already harbored defined deletions in both the aroC and aroD genes. The presence of the deletions within ompR was confirmed by Southern hybridization and sequencing of the DNA fragments surrounding the deleted regions by PCR. The S. typhi ompR mutants displayed a marked decrease in OmpC and OmpF porin expression as demonstrated by examination of outer membrane preparations. It was also found that S. typhi strains harboring the defined ompR deletions no longer agglutinated with Vi antiserum. However, when a functional ompB operon was introduced back into the S. typhi ompR mutants, either on a multicopy plasmid or as a single-copy chromosomal replacement, the Vi+ phenotype was restored. The levels of Vi synthesis were also found to be sensitive to different concentrations of sodium chloride present in the growth medium, although the levels of sensitivity varied between different isolates of S. typhi. It is therefore concluded that the ompR-envZ two component regulatory system plays an important role in the regulation of Vi polysaccharide synthesis in S. typhi and that one of the environmental signals for this regulation may be osmolarity.