Effect of the lactoperoxidase system on Listeria monocytogenes behavior in raw milk at refrigeration temperatures

Activity of raw milk lactoperoxidase-thiocyanate-hydrogen peroxide (LP) system on four Listeria monocytogenes strains at refrigeration temperatures after addition of 0.25 mM sodium thiocyanate and 0.25 mM hydrogen peroxide was studied. The LP system exhibited a bactericidal activity against L. monocytogenes at 4 and 8 degrees C; the activity was dependent on temperature, length of incubation, and strain of L. monocytogenes tested. D values in activated-LP system milk for the four strains tested ranged from 4.1 to 11.2 days at 4 degrees C and from 4.4 to 9.7 days at 8 degrees C. The lactoperoxidase level in raw milk declined during a 7-day incubation, the decrease being more pronounced at 8 degrees C than at 4 degrees C and in control milk than in activated-LP system milk. The thiocyanate concentration decreased considerably in activated-LP system milk at both temperatures during the first 8 h of incubation. LP system activation was shown to be a feasible procedure for controlling development of L. monocytogenes in raw milk at refrigeration temperatures.

Crystals of Anabaena PCC 7119 ferredoxin-NADP+ reductase

Crystals of ferredoxin-NADP+ reductase (FNR) from the cyanobacterium Anabaena PCC 7119 are grown in the presence of polyethylene glycol 6000 and beta-octyl glucoside. They belong to the hexagonal system. The cell parameters are a = b = 87.8 A, c = 92.7 A, space group P6(1) or P6(5), and a Vm of 3.0 A3/dalton for one molecule of 36,000 daltons per asymmetric unit. These crystals diffract strongly up to 1.9 A and are suitable for X-ray structural studies.

Influence of breed, animal, and days of lactation on lactoperoxidase system components in goat milk

Lactoperoxidase and thiocyanate content in goat milk from two Spanish breeds throughout 5 mo of lactation has been investigated. Mean lactoperoxidase for milk from Verata and Murciano-Granadina goats was .95 and 2.15 units/ml, respectively. Very low concentrations, .03 units/ml for Verata and .20 units/ml for Murciano-Granadina, were found for the first 24 h after kidding. Highest concentrations were detected at the end of lactation (135 to 150 d) for Verata and in midlactation (60 to 75 d) for Murciano-Granadina goats. Mean thiocyanate content was 5.76 ppm for Verata goats, without a distinct maximum throughout lactation, and 3.20 ppm for Murciano-Granadina goats, with maximum levels at final lactation stages. Activation of the lactoperoxidase system might be a useful procedure in preserving raw goat milk quality by addition of low levels of thiocyanate and hydrogen peroxide.

Cerebral venous malformations

Although cerebral venous malformations have been reported to cause epilepsy, progressive neurological deficits, and hemorrhage, their clinical significance remains controversial. In an attempt to clarify the natural history of the lesion and suggest an appropriate management strategy, the authors review their experience with 30 patients. In four patients with cerebellar venous angioma, an acute episode of ataxia was documented. The coexistence of a cavernous malformation was pathologically confirmed in the two patients who underwent surgery for bleeding presumed caused by the venous angioma. Infarction was shown in two patients and a tumor in two others. Follow-up periods ranged between 18 and 104 months, with only five patients symptomatic at the time of this report. Rebleeding had not occurred, nor had acute episodes of neurological dysfunction been documented. This clinical experience suggests that a venous malformation is frequently associated with other, more symptomatic conditions and is often erroneously identified as the source of the symptoms. Because the nature of the relationship between the venous malformation and the allied conditions remains ambiguous, it is recommended that patients harboring a "symptomatic" venous malformation undergo high-field magnetic resonance imaging to rule out underlying pathology, and that any such pathology be treated independently of the venous malformation.

Arginyl groups involved in the binding of Anabaena ferredoxin--NADP+ reductase to NADP+ and to ferredoxin

Chemical modification of ferredoxin--NADP+ reductase from the cyanobacteria Anabaena has been performed using the alpha-dicarbonyl reagent phenylglyoxal. Inactivation of both the diaphorase and cytochrome-c reductase activities, characteristic of the enzyme, indicates the involvement of one or more arginyl residues in the catalytic process of the enzyme. The determination of the rate constants for the inactivation process under different conditions, including those in which substrates, NADP+ and ferredoxin, as well as other NADP+ analogs were present, indicates the involvement of two different groups in the inactivation process, one that reacts very rapidly with the reagent (kobs = 8.3 M-1 min-1) and is responsible for the binding of NADP+, and a second less reactive group (kobs = 0.9 M-1 min-1), that is involved in the binding of ferredoxin. Radioactive labeling of the enzyme with [14C]phenylglyoxal confirms that two groups are modified while amino acid analysis of the modified protein indicates that the modified groups are arginine residues. The identification of the amino acid residues involved in binding and catalysis of the substrates of ferredoxin--NADP+ reductase will help to elucidate the mechanism of the reaction catalyzed by this important enzyme.

The contents of proteins, carbohydrates, lipids and DNA during the embryogenesis of Drosophila

The concentration of proteins, sugars, lipids and DNA has been determined during the embryogenesis of Drosophila. The protein content decreases after fertilization, being in the late embryo only 60% the value of the oocyte. The total sugar increases about 2.5-fold, from 3.5 h on until the end of embryogenesis. The lipids increase with a sharp peak at about 4 h and decrease during the rest of embryogenesis. DNA increases exponentially from the beginning of embryogenesis.

Modulation of luteinizing hormone secretion by estrogens in patients with Reifenstein's syndrome

The role of estrogens on gonadotropin secretion was assessed in two siblings with incomplete virilization syndrome type I due to partial androgen insensitivity (Reinfenstein's syndrome). Serum levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were measured before and after 100 micrograms LH-releasing hormone (RH) intravenous (IV) stimulation, as well as during long-term clomiphene citrate (CC) administration. Serum testosterone (T) and estrogens were determined before and during daily administration of human chronic gonadotropin (hCG) and also during the CC treatment. Basal levels of LH were elevated in both patients: 12.5 +/- 1.1 mIU in patient A and 19.8 +/- 1.8 mIU/ml in patient B. Conversely, FSH levels were within normal limits. Administration of LH-RH in both subjects induced a rise in LH levels, while FSH concentration showed no increase. The CC administration resulted in a significant (P less than 0.005) increment in serum LH levels without changes in FSH concentration. An important increase of serum T and estradiol (E2) levels was noted during CC administration; thus, in patient A those levels augmented from 20 to 48 ng/ml for T and from 78 to 220 pg/ml for E2; and patient B showed an increment from 20 to 35 ng/ml for T, and from 55 to 180 pg/ml for E2. The daily administration of hCG was followed by an increment in both T and E2 levels, which was of lesser degree for estrone concentration. These results suggest that endogenous estrogens, particularly E2, modulate LH secretion in patients with partial androgen insensitivity; however, it appears that estrogens had no physiologic effect on FSH secretion.

Unenhanced and gadolinium-DTPA-enhanced MR imaging in postoperative evaluation in pediatric brain tumors

Gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) is a chelated paramagnetic contrast agent under clinical trial for use in magnetic resonance (MR) imaging. The increased signal intensity following the intravenous infusion of contrast medium may improve the ability of MR imaging to delineate tumors. The use of this method in 15 pediatric patients with suspected brain-tumor recurrence was analyzed. All 15 patients underwent postoperative Gd-DTPA-enhanced MR imaging, and residual tumor was demonstrated in nine of them. Based on the findings of the enhanced MR studies, four patients had additional surgery, two underwent radiation therapy, and one was given immunotherapy. Continued surveillance was recommended for the remaining eight patients. In all cases the enhanced MR imaging studies were superior to the unenhanced studies in regard to the qualitative and quantitative assessment of the residual tumor. Gadolinium-DTPA-enhanced MR imaging appears to be a safe and effective means of providing an accurate postoperative assessment of residual disease in pediatric brain-tumor patients. It is as effective as contrast-enhanced computerized tomography and has the sensitivity and anatomic resolution provided by MR imaging. The most useful role of this agent was in the postoperative period, in assessing the adequacy of surgical resection. This technique is recommended as the procedure of choice in the postoperative assessment and long-term surveillance of patients with brain tumors.

An aspartic proteinase in Drosophila: maternal origin and yolk localization

An aspartic proteinase activity has been found in Drosophila oocytes and embryos. The proteinase is maximally active at pH 3.5 and has been characterized by its sensitivity to specific inhibitors and by the specificity of cleavage. The activity is very low and has been localized in the yolk granules. The proteinase is detected in mature oocytes (i.e., it is of maternal origin) and remains essentially constant during embryogenesis. This suggests that the Drosophila aspartic proteinase functions mainly before embryogenesis.

[Neurologic disorders in children with chronic terminal renal insufficiency]

Neurological alterations are very frequent in children with end stage renal disease (ESRD). In order to assess the type of these complications, a neurological study was undertaken in 30 children with ESRD. Three of the patients had convulsions and hyperreflexia was the only clinical sign found in all the patients. Low serum levels of hemoglobin and calcium and high concentrations of phosphates, aluminum and parathyroid hormone were found in all cases, but correlations with any neurological alteration were not made. Abnormal EEG with slow waves in the occipital region were obtained in 23 patients. Sensorial hypoacusia was registered in 6 children who were previously treated with aminoglucosides. The cerebral tomography showed calcifications in three instances, but only in one patient were of clinical significance. In five, out of the 30 patients, cerebral atrophy was detected. In conclusion, assessment of the neurological condition is mandatory in children with ESRD before renal transplantation is performed, since the complication itself or the therapy may interfere with rehabilitation.

Gd-DTPA-enhanced MR imaging in pediatric patients after brain tumor resection

A prospective study was conducted in 15 pediatric patients who had undergone resection of intracranial tumors. The object of the study was to determine the safety and efficacy of magnetic resonance (MR) imaging performed after the administration of gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) in evaluating residual or recurrent tumor. Precontrast T1-weighted, intermediate, and T2-weighted images were obtained at a field strength of 1.5 T. Gd-DTPA was then injected intravenously in a dose of 0.1 mmol per kilogram of body weight. T1-weighted images were obtained within 5 minutes after the injection, intermediate and T2-weighted images were obtained 10 minutes after the injection, and T1-weighted images were obtained approximately 20 minutes after the injection. None of the patients experienced allergic reactions or other side effects. Physical examination findings and laboratory values were unchanged after the Gd-DTPA-enhanced examination. In six patients, contrast-enhanced images depicted tumor not suspected on nonenhanced images. In four other patients, enhanced images provided better definition of the tumor core. The images of one patient with a brain stem tumor showed no evidence of enhancement. Pre- and postcontrast images of three previously treated patients showed no evidence of tumor. Gd-DTPA appears to be a safe and effective contrast agent for MR imaging and provides a more accurate method of imaging in the follow-up of brain tumors in pediatric patients.

Neuralgia of the intermediate nerve combined with trigeminal neuralgia: case report

An unusual case of a combination of trigeminal and intermediate nerve neuralgia is presented, caused by vascular compression of both of the nerve roots by different vessels. Because the neuralgia of the intermediate nerve could be cured by a vascular decompression operation, it is suggested to include it among the hyperactive dysfunction syndromes of cranial nerves caused by vascular compression at the root entry zone of the nerves. Therefore also for treatment of this neuralgia the non-destructive vascular decompression operation should be taken into consideration.

Staphylococcus aureus, thermostable nuclease and staphylococcal enterotoxins in raw ewes' milk Manchego cheese

Growth and survival of two enterotoxigenic strains of Staphylococcus aureus were studied during manufacture and ripening of eight batches of raw ewes' milk Manchego cheese. Only 2-3 generations of Staph. aureus occurred in the vat and during pressing. The death rate of Staph. aureus (mean decrease in log cfu/g/week of ripening) from day 1 to day 60 was 0.421 in cheese made with 1% Streptococcus lactis starter and 0.404 in cheese made without starter. Thermostable nuclease was produced in the vat by growing Staph. aureus cells; it was inactivated by rennet during the first 24 h and synthesized again by surviving cells of Staph. aureus from day 1 to day 60. Staphylococcal enterotoxins A, B, C and D were not detected in any batches of cheese, even though Staph. aureus counts exceeded 10(7) cfu/g.

Drosophila cathepsin B-like proteinase: a suggested role in yolk degradation

A cysteine, cathepsin B-like proteinase activity has been found in Drosophila embryos. It appears associated with yolk granules and its activity during embryogenesis correlates well with the degradation of these organelles. In mature oocytes, the enzyme is found in an inactive form which may be activated by limited proteolysis by a serine proteinase also present in oocytes. In early embryos, when solubilized in vitro, the cathepsin B-like proteinase is found in a form of high molecular mass (approx 1000 kDa). This decreases with development down to about 39 kDa, likely the mass of the free proteinase. The heavy form apparently results from the tight association with a yolk protein complex. The proteinase has been found in vitro to degrade readily the yolk polypeptides. The proteinase activity increases during early embryogenesis in parallel with the decrease in molecular weight of the heavy form, and decreases to low values in late embryos. We have also found that ammonium chloride can inhibit in vivo the degradation of yolk and, in parallel, the developmental inactivation of the proteinase. The results altogether suggest that the cathepsin B-like proteinase is implicated in yolk degradation in Drosophila.

Influence of lactic starter inoculation, curd heating and ripening temperature on Staphylococcus aureus behaviour in Manchego cheese

Growth and survival of Staphylococcus aureus were investigated in 52 lots of raw ewe's milk Manchego cheese manufactured and ripened under different conditions. A 5.8-fold reduction in S. aureus counts after 60 days of ripening was obtained by inoculating milk with 1% Streptococcus lactis culture, and a further 2.0-fold reduction could be achieved by adding 0.1% Lactobacillus plantarum culture. Curd heating temperature had a significant effect on S. aureus survival, with counts 4-5 times lower in cheese from 30 degrees C curd than in cheese from curd heated at 36-40 degrees C. Ripening temperature was the parameter with the greatest influence on S. aureus counts, which reached in cheese cured at 10 degrees C or 20 degrees C for 60 days levels 10 and 100 times lower, respectively, than in cheese held at 5 degrees C.

A quantitative study of enterotoxin production by sheep milk staphylococci

Of 124 staphylococcal strains isolated from sheep milk, 78 produced enterotoxin A, B, C, or D when evaluated by an enzyme-linked immunosorbent assay. Enterotoxins A and D, elaborated by 44 and 43 strains, respectively, showed the highest incidence. Enterotoxin production by coagulase-negative strains (one Staphylococcus cohnii, three S. epidermidis, five S. haemolyticus, and four S. xylosus) was detected. Linear and logarithmic-logarithmic regressions of optical density on enterotoxin concentration yielded the best-fitting equations for enterotoxin quantitation. A significantly higher incidence of enterotoxin producers and significantly higher levels of enterotoxins produced were recorded for coagulase-positive, thermostable nuclease-positive, hemolysis-positive, or mannitol-positive strains. Mannitol utilization was the best test for discriminating between enterotoxigenic and nonenterotoxigenic staphylococci.

Amyloidoma of the cervical spine: a case report

This is the first published report of an amyloidoma localized to the cervical spine. Primary amyloidosis of bone is rare. Only 5 cases involving the spine have been described. We present a 74-year-old man with cervical and occipital radicular pain as the manifestations of an amyloidoma involving the 2nd cervical vertebra. The signs and symptoms of this disease, when localized to the vertebrae, are nonspecific and result from bony destruction and compression of neural structures. Diagnosis requires a high index of suspicion and, ultimately, adequate tissue biopsy for histopathological studies. Curative resection is possible for well-localized lesions. Additionally, external immobilization with a halo vest and bony grafting for fusion may be indicated when the cervical spine is involved.

Cerebral scintigraphy with 111indium oxine-labelled leukocytes in the differential diagnosis of intracerebral cystic lesions

CT scanning and scintigraphy with 111Indium-oxide-labelled white blood cells were used to study 32 cases of intracerebral cystic lesions. The results and the criteria of positivity used to lower the false positive rate are discussed. A new criterion, designed to assess the time course of the scintiscan and so reduce still further the frequency of false positives is put forward.

Chronic extradural hematomas of the posterior cranial fossa

During the past 6 years, seven patients with chronic extradural hematomas have been observed at these hospitals. All had a history of occipital injury. Occipital fracture was demonstrated in five cases (by skull x-ray in three cases, at operation in two). The diagnosis was obtained by computed tomography scan in six cases and by iodoventriculography in one. One patient had an associated cerebral lesion, namely, a contralateral temporoparietal contusion. The interval between injury and operation ranged from 27 to 13 days with a mean of 19 days. Only one patient was not operated on, because he was free from symptoms and the hematoma was small. The course was excellent in all seven cases.