PubMed Health⌕ Search

Biomedical subjects

H Kuiper

Publications and source records attributed to H Kuiper.

At least 91 records · Page 5Linked to original sources
PubMed1993

Mannitol-specific enzyme II of the phosphoenolpyruvate-dependent phosphotransferase system of Escherichia coli: physical size of enzyme IImtl and its domains IIBA and IIC in the active state.

The size of enzyme IImtl solubilized in the active state has been determined by size-exclusion chromatography under conditions that favor the association of the enzyme. The contribution of the detergent bound to the enzyme was determined by solubilizing the enzyme and running the TSK250 column in a number of detergents with decreasing micellar sizes. The size, expressed as the equivalent molecular mass of a globular protein, decreased from 315 kDa in decylPEG, to 275 kDa in octylPEG and octyl glucoside, and then to 245 kDa in cholate. Enzyme IImtl is not active in the latter three detergents when at concentrations above their cmc values but still binds mannitol with high affinity without significant loss of sites. This, together with the full reversibility of the inactivation, is taken as evidence that the enzyme does not unfold or dissociate in these detergents. The sizes of the separated domains IIBA and IIC of enzyme IImtl were 38 and 175 kDa, respectively. The cytoplasmic domain, IIBA, was monomeric at high concentration, whereas the membrane-bound domain, IIC, was associated at much lower concentration. Apparently, the sites that interact to keep enzyme IImtl in the associated state are exclusively located in the membrane-bound domain.

Binding Sites↗
PubMed1993

One year follow-up study to assess the prevalence and incidence of Lyme borreliosis among Dutch forestry workers.

A one-year serological and clinical follow-up study was conducted to assess the prevalence and incidence of asymptomatic and symptomatic infection with Borrelia burgdorferi among 151 Dutch forestry workers. The prevalence of antibodies to Borrelia burgdorferi among the forestry workers and among office employees as control group was compared. Antibodies to Borrelia burgdorferi were detected by enzyme immunoassay. Forestry workers were examined physically at the start of the study. Clinical follow-up of forestry workers whose first blood sample was positive and of persons showing seroconversion was done by telephone interview. If Lyme borreliosis was suspected, clinical and laboratory data were obtained. The seroprevalence was significantly higher among forestry workers (28%) than among controls (5%). Of 127 forestry workers who were examined, 7 (18%) of the 39 seropositive persons but none of the seronegative persons had a history of Lyme borreliosis. None of 32 asymptomatic seropositive forestry workers had developed Lyme borreliosis one year later. The incidence of infection with Borrelia burgdorferi as demonstrated by seroconversion among 95 initially seronegative forestry workers was 5%. None of them had Lyme borreliosis. Infection with Borrelia burgdorferi among forestry workers is frequent but seems to take a benign course.

Adult↗
PubMed1993

Different genospecies of Borrelia burgdorferi are associated with distinct clinical manifestations of Lyme borreliosis.

Borrelia burgdorferi sensu lato has been subdivided into three genospecies: B. burgdorferi sensu stricto, B. garinii, and B. burgdorferi group VS461. Sixty-eight isolates cultured from patients and 26 strains from ticks were characterized with use of SDS-PAGE, western blotting, and rRNA gene restriction analysis. Fifty-seven of 58 strains obtained from the skin of 70 patients who had erythema migrams or acrodermatitis chronica atrophicans were of group VS461, whereas the genotype of the remaining strain was unidentifiable. Of 10 strains cultured from CSF (n = 3) and skin (n = 7) of 20 patients with extracutaneous symptoms of Lyme borreliosis, nine were B. garinii and one was B. burgdorferi sensu stricto. Of these 20 patients, 17 had neuroborreliosis, one had arthritis and carditis, one had myalgia, and one had erythema and arthralgia. All 26 isolates from ticks were of group VS461. In conclusion, infections due to group VS461 and B. garinii are associated with cutaneous and extracutaneous symptoms, respectively. Our findings suggest that B. burgdorferi genotypes have different pathogenic potentials.

Acrodermatitis↗
PubMed1993

Uveitis and Lyme borreliosis.

In a retrospective study 56 consecutive patients with uveitis of unknown origin and 56 consecutive patients suffering from uveitis of established aetiology were investigated. The purpose of this study was to determine the frequency of positive serological tests for Lyme borreliosis among patients with uveitis and to relate laboratory data to clinical findings. The antibody titre for Borrelia burgdorferi was determined by two assays: the indirect immunofluorescence assay and the enzyme linked immunosorbent assay. A positive result according to one or both assays was found for eight patients with uveitis of unknown aetiology (14%) and three patients with uveitis of established cause (5%). On clinical examination, none of the patients fulfilled the CDC criteria for diagnosis of Lyme borreliosis.

Antibodies, Bacterial↗
PubMed1992

Absence of Lyme borreliosis among patients with presumed Bell's palsy.

In a prospective study, 69 patients with a presumed idiopathic (Bell's) peripheral facial palsy were clinically and serologically evaluated for the presence of Lyme borreliosis. In addition, their clinical spectrum was compared with clinical manifestations collected retrospectively in nine patients with symptomatic peripheral facial palsy due to Lyme borreliosis. The seroprevalence of Borrelia burgdorferi antibodies, determined by flagellum enzyme-linked immunosorbent assay, among 69 patients with idiopathic peripheral facial palsy (6%) and 153 healthy controls (4.5%) was not significantly different (odds ratio, 1.28; 95% confidence interval, 0.27 to 5.25). None of the patients with idiopathic peripheral facial palsy had or experienced the development of Lyme borreliosis. All patients with Lyme peripheral facial palsy had additional manifestations not present in patients with idiopathic peripheral facial palsy. These findings show that patients with a Lyme peripheral facial palsy can be differentiated from patients with idiopathic peripheral facial palsy by clinical examination. Therefore, screening of antibodies to B burgdorferi among patients with idiopathic peripheral facial palsy without additional manifestations is not recommended.

Adolescent↗
PubMed1992

Intermediate uveitis and Lyme borreliosis.

A case of chronic intermediate uveitis and associated classic snowbanking (pars planitis) with severe cystoid macular oedema probably due to Lyme borreliosis is reported. Despite a disease duration of 10 years the patient's ocular symptoms and visual acuity responded promptly to intravenous ceftriaxone treatment. This case demonstrates that periodic reevaluation of patients with intermediate uveitis is necessary to obtain a specific diagnosis which may include Lyme borreliosis.

Adult↗
PubMed1991

[Aspecific eye disorders in Lyme disease].

Lyme disease shows a large variety of clinical signs and symptoms. Ocular disease may occur in the disseminated stage of the disease. Ocular signs are often not specific of Lyme disease. In the presence of unexplained ocular disease it may be wise to consider Lyme disease as a possible diagnosis. Diagnosis and therapy in two Lyme disease patients with ocular disease are discussed.

Adult↗
PubMed1991

Lyme borreliosis in Dutch forestry workers.

Serum samples from 127 Dutch forestry workers and 127 matched controls were tested for antibodies against Borrelia burgdorferi in an indirect immunofluorescence assay (IFA). Those of the forestry workers were also tested by Western blotting. The forestry workers were examined clinically for evidence of Lyme borreliosis without the examiner or the workers knowing the results of the laboratory tests. Seroprevalence of B. burgdorferi antibodies among forestry workers (25/127) was significantly higher than among controls matched for age and place of residence (8/127), odds ratio 3.7 (95% CI 1.5-9.7). Of the 25 sera of forestry workers positive in the IFA, 23 reacted with at least five bacterial polypeptides in the Western blot test. According to adapted CDC criteria, seven forestry workers (6%) were classified as being a case of Lyme borreliosis. In only one of them had the diagnosis been made before this investigation. Five persons had a history of erythema migrans, one of arthritis, and one of persistent infection. We conclude that Lyme borreliosis is an occupational disease among forestry workers in the Netherlands, with a three-fold higher seroprevalence than among matched controls. The disease, often not diagnosed among this high-risk group, warrants more attention to achieve early recognition and to prevent late complications.

Adult↗
PubMed1991

The hearing loss associated with exposure to toluene is not caused by a metabolite.

Exposure to toluene causes a marked hearing loss in rats, and this effect has been observed in some human solvent abusers. The issue of whether toluene or one of its metabolites is responsible for this effect has not been examined. To attempt to resolve this issue, we manipulated the metabolism, and thus the circulating levels, of toluene as follows. Two groups of rats were exposed to phenobarbital (PB) in their drinking water (0.1%) for seven days to induce detoxifying liver enzymes; two other groups had access to PB-free water. Then half of the rats exposed to PB or water were exposed to filtered air or a concentration of toluene expected to cause hearing loss. Levels of toluene in blood were markedly reduced by the PB and the excretion of hippuric acid was increased. All rats were tested for auditory sensitivity by brainstem auditory-evoked response (BAER) audiometry using a 16-kHz tone pip. The rats exposed to toluene alone showed a marked reduction in the integrated BAER waveform, indicative of the expected hearing deficit. None of the other treated rats showed any deviation from controls (i.e., water and air). These results provide strong evidence that toluene itself is responsible for the auditory dysfunction. Toluene also caused the rats to increase their fluid consumption and urine output; these effects were not altered by PB. Identification of toluene as the proximal ototoxicant should facilitate the search for the mechanism of this effect.

Acoustic Stimulation↗
PubMed1987

Gliomatosis cerebri, report of a clinically diagnosed and histologically confirmed case.

Pathological criteria for diffuse gliomatosis are clearly demarcated but its clinical diagnosis has always been hampered by the imaging techniques used. Although with the advent of CT scanning clinical possibilities were improved, isodense brain lesions are difficult to detect and in these cases the diagnosis gliomatosis cerebri can only be suspected from the clinical signs and the absence of radiological signs. We have studied a young patient with a peculiar clinical history, in whom comparison of the CT-scan and NMR scan yielded remarkable results. Our clinical diagnosis of (diffuse) gliomatosis was confirmed by biopsy.

Adolescent↗
PubMed1986

Discrimination of tertiary and quaternary Bohr effect in the O2 binding of Helix pomatia beta-hemocyanin.

Simultaneous determination of proton uptake and oxygen binding has been carried out on Helix pomatia beta-hemocyanin under equilibrium conditions in the absence of buffer and at different initial pH values. Oxygen-binding isotherms of unbuffered H. pomatia beta-hemocyanin, in the presence of phenol red as pH indicator, have been determined employing a thin-layer apparatus. Application of this very accurate technique allows monitoring of proton uptake (or release) coupled to O2-binding also at extremes of saturation which are often difficult to explore and analyze. The data have been analyzed within the framework of the cooperon model (M. Brunori, M. Coletta and E. Di Cera, Biophys. Chem. 23 (1986) 215) and compared with those obtained in the presence of buffer. Comparison of pH changes with ligand binding of the T state over all the saturation range has allowed us to discriminate and obtain quantitative estimates of the Bohr protons associated with both oxygenation of the T state and quaternary allosteric transition; no protons are taken up or released during oxygenation of the R state. These results differ quantitatively from those obtained in the presence of buffer, which alters significantly the T state contribution to the overall Bohr effect.

Journal Article↗