Sensitivity of laser-evoked potentials versus somatosensory evoked potentials in patients with multiple sclerosis.

OBJECTIVE: Somatosensory evoked potentials (SEPs) play a less important role in the diagnosis of multiple sclerosis (MS) than visually evoked potentials. Since standard SEPs only reflect the dorsal column function, we now investigated spinothalamic tract function in patients with MS using laser-evoked potentials (LEPs). METHODS: LEPs to thulium laser stimuli (3ms, 540 mJ, 5mm diameter) were recorded from 3 midline positions (Fz, Cz, Pz) in 20 patients with MS, and 6 patients with possible but unconfirmed MS. Peak latencies and peak-to-peak amplitude of the vertex potential negativity (N2) and positivity (P2) were evaluated and compared with normative values from 22 healthy control subjects. Median and tibial nerve SEPs were recorded with standard methods. Depending on the results of sensory testing, two skin areas (both hands, both feet, or one hand and foot of the same body side) were assessed in each patient. RESULTS: In group comparisons, LEPs in patients with MS were significantly delayed and reduced in amplitude compared with healthy subjects (P<0.001) or patients with suspected but unconfirmed MS (P<0.05). In intraindividual comparisons within the patients with MS, LEP amplitude was significantly lower (P<0.01) and latencies were significantly longer (N2: P<0.01; P2: P<0.05) for a clinically hypoalgesic skin area than an unaffected control area. On a single case basis, LEPs were abnormal in 12 (60%) and SEPs in 8 (40%) of the patients with MS; combined analysis of LEPs and SEPs raised sensitivity to 75% (15 patients). LEPs were also abnormal for 7 skin areas with clinically normal nociception and thermal sensitivity, indicating subclinical lesions. Standard SEPs detected subclinical lesions in 5 areas with normal tactile sensitivity. CONCLUSIONS: In patients with multiple sclerosis, spinothalamic tract function and LEPs were impaired more often than dorsal column function and SEPs. LEPs also detected subclinical lesions. Combined assessment of LEPs and SEPs can help to document dissemination of demyelinating CNS lesions and thus contribute to the diagnosis of multiple sclerosis.     

Parvovirus B19 infection of the fetus. Histology and in situ hybridization.

Fetal tissues from 16 spontaneous abortions, two terminations, and one perinatal death, 18 of which were associated with maternal human parvovirus B19 infection, were examined for B19 infection by histology and in situ hybridization using a digoxigenin-labeled B19-DNA probe. In 15 spontaneous abortions and one termination, erythroblasts with intranuclear inclusions (lantern cells) reacted with B19-DNA by in situ hybridization. No internal or external fetal malformations were observed. Because 13 (86.7%) spontaneous abortions with lantern cells occurred between the 20th and 28th weeks of gestation, it is postulated that B19 infection may be a particular threat to the fetus during this stage of gestation.     

CT and MR imaging findings in adults with cerebellar medulloblastoma: comparison with findings in children.

The goal of this study was to determine if certain imaging features suggest the diagnosis of cerebellar medulloblastoma in adults and to determine how often the classic CT appearance seen in children is present in adults. The study included 28 adult patients with proved cerebellar medulloblastoma. The tumor was located in the cerebellar vermis in 14 patients and in a cerebellar hemisphere in 14 patients. Thirteen patients had unenhanced CT of the brain, all patients had contrast-enhanced CT, and eight patients had unenhanced MR imaging. The imaging features in adults were compared with those in children, as described in the literature. In our adult patients, all tumors were hyperdense compared with gray matter on unenhanced CT and showed a slight to moderate increase in density after injection of contrast medium. Thirteen lesions had well-defined margins, and 15 had poorly defined margins. Low-density areas consistent with cystic and necrotic degeneration were detected in 23 (82%) of the 28 tumors. By comparison, in children, medulloblastoma usually originates in the vermis. As in adults, the mass is hyperdense on unenhanced CT, but enhances markedly and homogeneously after injection of contrast medium. Usually no evidence of cyst formation or necrosis is seen, and the tumor margins are well defined. This classic CT appearance of medulloblastoma in children was identified in only three (11%) of the 28 adult patients. Medulloblastoma has a variable MR appearance in both children and adults. On T2-weighted images, lesions are hypo-, iso-, or hyperintense compared with normal gray matter. The CT findings of medulloblastoma in adults usually differ from those of medulloblastoma in children. The tumor has a variable and nonspecific appearance in adults and should always be considered in the differential diagnosis of a mass in the posterior fossa.     

Porphyria cutanea tarda associated with autoimmune hypothyroidism, vitiligo and alopecia universalis.

The aetiology of porphyria cutanea tarda (PCT) has not been elucidated, but the possibility of an autoimmune mechanism has been proposed. We report a case of an unknown clinical combination of PCT with autoimmune hypothyroidism, alopecia universalis and vitiligo with thyroid and parietal cell circulating antibodies. This is highly suggestive of underlying autoimmune damage in this patient.     

The cardioprotective action of nifedipine during short-term transient ischemia

To determine the therapeutic activity on regional myocardial function of nifedipine intravenous administration (0.16 mg/kg) during short term myocardial induced ischemia, we used 6 mongrel dogs anesthetized and intubated those who we have implanted 3 pairs of ultrasonic crystals in the subendocardial layer. Utilizing an open chest canine model we performed total 1 minute and partial 2 minutes 30 seconds alternative obstructions, controlled with electromagnetic flowmeters in the anterior descending (AD) and circumflex (Cx) coronary arteries before and after drug administration. During the 70-80% obstructions we have shown a significant improvement in segment shortening, reduced by ischemia, in the ischemic and peri-ischemic zone. The ischemic markers, per cent increment of end diastolic length (% IEDL) and per cent increment of end systolic length (% IESL), have shown significant improvement during partial obstructions in the ischemic and peri-ischemic zone. After total obstructions the improvement on regional myocardial function is less marked and limited to ischemic zone.     

Immunochemical changes in the outer membrane of Escherichia coli adapted to amine oxides]

Resistant strains of Escherichia coli were obtained by stepwise cultivation in subinhibitory concentrations of two antimicrobially active amine oxides. Changes in the chemical composition of the outer membrane of the resistant strains were accompanied also by different antigenic reactions. New precipitation lines were revealed by double immunodiffusion and immuno-electrophoretic methods. The results of immunochemical analysis confirm the findings that the resistance to amphiphilic compounds is associated with the outer membrane which limits the access of antimicrobially active molecules to their sites of action in the cytoplasmic membrane.     

Diagnosis of hairy leukoplakia by exfoliative cytologic methods.

The cytologic characteristics of hairy leukoplakia (HL) are described based on the findings observed in four lesions. All cases were confirmed by histologic study, and Epstein-Barr virus DNA was detected by means of in situ hybridization of tissue sections. All smears from the lesions exhibited a distinctive appearance and three types of epithelial changes were observed: (1) intranuclear inclusions of Cowdry type A, (2) intranuclear inclusions with a ground-glass appearance, and (3) clumping and margination of chromatin around the nuclear membrane. Other findings were the presence of bacterial colonies in all lesions and Candida organisms in three of them. The results of this study suggest that conventional exfoliative cytologic examination may prove to be a useful, simple, cost-effective, and reliable method to diagnose hairy leukoplakia.     

The health impact of stray and wild cats in the human environment]

The population of stray cats in towns expands due to irresponsible behaviour of humans who allow them to enter cellars, hot water canals, store rooms etc. As a result of frequent feeding some specimens become tame, lose their shyness and on contact with humans and domestic animals they can become the source of some infectious agents. The most important of thus transmitted diseases is rabies. Cats become infected from foxes on rubbish heaps on the periphery of communities. More than 60% of cases of rabies of domestic animals are found in cats. Toxoplasmosis--cats excrete the infectious stage of the causal agent in their excreta. In the same manner also the agent causing intestinal salmonelloses is excreted. More than 5% cats are infected. Via excreta also the causal agents of toxocariasis are spread--the larvae of cat thread worms settle in the internal organs of humans (larva migrans). The assumed incidence in cats is as high as 50%, as suggested also by the high positivity of specimens from children playgrounds. Stray cats may be the source of agents causing various dermatomycoses and of ectoparasites.     

Tracheostomy in spinal cord injured: frequency and follow up.

Among 600 traumatic spinal cord injured (SCI) patients admitted during a 20 year period, 67 had a tracheostomy performed (11.2%). Of these 67 patients 46 had a cervical SCI. A concomitant thoracic trauma had occurred significantly more often in the group with thoracic or lumbar SCI than in those with a cervical SCI. The period from injury to tracheostomy was 0-48 days (median 4.4 days), and from tracheostomy to decannulation 3-167 days (median 31 days). At follow up 20 (30%) had died, primarily because of respiratory problems. Of the remaining 47 patients, 43 (91%) responded to a follow up questionnaire 3.5-21.7 years (median 10.4 years) after the injury. In the follow up 53% reported never to have had any inconvenience or trouble related to the tracheostomy. The major inconvenience among the others had been of cosmetic origin (28%), and 3 had had a surgical revision for this reason. At the time of follow up 9 patients (21%) still had certain complaints, primarily described as difficulty in swallowing. Minitracheostomy might in the future reduce the number of these complications.