Nosocomial outbreak of respiratory tract colonization with Mycobacterium fortuitum: demonstration of the usefulness of pulsed-field gel electrophoresis in an epidemiologic investigation

Between August 1989 and January 1990, 16 patients on an alcoholism rehabilitation ward (ARW) developed positive sputum cultures for Mycobacterium fortuitum. During a 2-wk surveillance period, six of 43 ARW patients but none of 20 staff members had positive sputum cultures. In addition, none of 54 patients and staff on an adjacent ward sharing the same ice machine and water supply had positive cultures, and none of 92 acid-fast bacilli cultures performed on all sputum specimens from all other inpatient sources during the same 2-wk period were positive. The only exposure factor common to all cases was the use of one or both of the ward showers. Compared with 36 ARW control patients, cases were more likely to report clinical criteria for chronic bronchitis (odds ratio, 6.6; 95% confidence interval, 1.5 to 28.6; p = 0.02). Using phenotype analysis, plasmid profiles, and pulsed-field gel electrophoresis of large genomic DNA restriction enzyme fragments, the 16 case isolates were found to be identical. This strain of M. fortuitum was also cultured from a tap connected to the water line supplying the ARW showers, but not from the showers themselves. No further cases were identified after the showers were disconnected and decontaminated. To our knowledge, this is the first clinical use of pulsed-field gel electrophoresis for genetic comparison of mycobacterial strains. It demonstrates the important potential of this technique for studying the epidemiology of mycobacterial infections. Showers should be considered a possible source of nosocomial respiratory tract colonization with M. fortuitum.

[Role of the nucleus vestibularis medialis in vestibulo-sympathetic response in rats]

Experiments were performed on rats anesthetized with alpha-chloralose and urethane. The sympathetic response evoked by stimulation of the vestibular nerve root at its entrance to brain-stem was recorded from the ipsi-splanchnic nerve. Electrical stimulation of the vestibular nerve elecited a distinct averaged response in the ipsilateral splanchnic nerve. The mean latency of response was 45.8 +/- 6.98 ms with a duration of 55.21 +/- 5.35 ms. With increasing the strength of stimulation, the amplitude of response was increased, but the latency was unchanged. By monitoring the lamellar field potentials in NVM and choosing the locus of phase-reversal of field potential as the stimulating site, an averaged response in ipsi-splanchnic nerve with a latency of 32 ms was obtained, while the recorded splanchnic nerve response had a latency of 43 ms, when the vestibular nerve was stimulated. After electrolytic lesion of the rostral part of ipsi-NVM, the vestibulo-sympathetic response was significantly reduced. When a second lesion was placed in the caudal NVM, the response disappeared. Lesion in Deiters' nucleus had no effect on the vestibulo-sympathetic response. The results suggest that NVM is a critical relay station in vestibulo-sympathetic response recorded in the splanchnic nerve.

Clinical disease, drug susceptibility, and biochemical patterns of the unnamed third biovariant complex of Mycobacterium fortuitum

Previous studies of Mycobacterium fortuitum identified isolates that did not fit its two recognized biovariants. Eighty-five clinical isolates of this group, the "third biovariant complex", were evaluated. They represented 16% of 410 isolates of M. fortuitum submitted to a Texas laboratory and 22% of 45 isolates in Queensland, Australia. Most infections (76%) involved skin, soft tissue, or bone and occurred after metal puncture wounds or open fractures. Isolates differed from biovar fortuitum in resistance to pipemidic acid and use of mannitol and inositol as carbon sources. Two subgroups were present, and examples were deposited in the American Type Culture Collection. Isolates were resistant to doxycycline and one-third were resistant to cefoxitin. All were susceptible to amikacin, ciprofloxacin, sulfamethoxazole, and imipenem. Surgical debridement combined with drug therapy based on in vitro susceptibilities resulted in cures of cutaneous disease or osteomyelitis. DNA homology studies are needed to determine the taxonomic status of these organisms.

Initial purification and characterization of hepatic microsomal cytochrome P-450 from BNF-treated perch (Perca fluviatilis)

1. A procedure was developed for isolating and purifying cytochrome P-450 from hepatic microsomes of BNF-treated perch, using modified versions of the methods of Williams and Buhler (1982. Biochim. biophys. Acta 717, 398-404) and Goksøyr (1985. Biochim. biophys. Acta 850, 409-417). 2. Following chromatography on phenyl-Sepharose CL 4B and DEAE-Sepharose CL-6B, the major peaks, fractions b and c, were resolved into five fractions, possibly representing different isoenzymes, by a FPLC with a strong anion exchange column (Mono Q). 3. These fractions have been characterized on the basis of their spectral, electrophoretic and immunological properties. 4. The purified form of cytochrome P-450 in fraction V from perch liver showed a number of similarities to cytochrome P-450c, the major BNF-inducible cytochrome P-450 in cod liver. 5. Therefore we suggest that this purified form of cytochrome P-450 is a BNF-induced form in perch and that it is closely related to the gene subfamily cytochrome P-450 IA1.

Cefotaxime-resistant Nocardia asteroides strains are isolates of the controversial species Nocardia farcinica

A recent study of Nocardia asteroides revealed that 95% of clinical strains had one of five antibiotic resistance patterns. We found the pattern of resistance to cefotaxime and cefamandole in 19% of 200 clinical N. asteroides isolates. Isolates with this drug resistance pattern were from numerous geographic sources and were associated with significant clinical disease (56% of patients had disseminated infections). Phenotypic studies revealed that these isolates were relatively homogeneous and matched previous descriptions and reference strains of the controversial species N. farcinica. Growth at 45 degrees C, acid production from rhamnose, ability to utilize acetamide as a nitrogen and carbon source, and resistance to tobramycin and cefamandole were features of N. farcinica that could be tested in the clinical laboratory and allowed their distinction from N. asteroides. The serious nature of disease due to N. farcinica and its resistance to the newer cephalosporins suggest a clinical need for laboratory identification of this species. (Current tests used in clinical laboratories do not distinguish N. farcinica from N. asteroides.) This is the first recognition that N. farcinica has a specific drug resistance pattern and confirms the previously described concept that drug resistance patterns of N. asteroides may be associated with specific taxonomic groups.

Preliminary crystallographic analysis of deshexapeptide (B25-B30) insulin

Satisfactory single crystals of deshexapeptide (B25-B30) insulin for X-ray crystal structure analysis have been grown in citrate buffer by the method of hanging-drop gas phase diffusion. The crystal belongs to the monoclinic system with space group C2. The unit cell constants are a = 42.6 A, b = 37.9 A, c = 27.2 A, beta = 125.4 degrees and there is only one molecule of deshexapeptide insulin in an asymmetric unit.

Antimutagenic effect of garlic (Allium sativum L.) on 4NQO-induced mutagenesis in Escherichia coli WP2

Aqueous extract prepared from garlic bulbs markedly suppressed the mutagenesis in both E. coli WP2 trp- and E. coli WP2 trp- uvrA- induced by 4-nitroquinoline 1-oxide (4NQO), but not that induced by UV. Cellular toxicity, inhibition of the expression of the Trp+ phenotype and delay of the first cell division after 4NQO treatment were not observed in the presence of the extract. Since the extract showed identical antimutagenic effects against 4NQO in both test strains but no effect on the mutagenesis of UV, it seems that the extract might act by inactivating the electrophilic group(s) of 4NQO or inhibiting its metabolic activation.

Primary structure of two neuropeptide hormones with adipokinetic and hypotrehalosemic activity isolated from the corpora cardiaca of horse flies (Diptera)

The primary structures of two neuropeptides, Tabanus atratus adipokinetic hormone (Taa-AKH) and Tabanus atratus hypotrehalosemic hormone (Taa-HoTH), from the corpora cardiaca of horse flies (Diptera: Tabanidae) have been determined. Amino acid sequences of Taa-AKH (less than Glu-Leu-Thr-Phe-Thr-Pro-Gly-Trp-NH2) and Taa-HoTH (less than Glu-Leu-Thr-Phe-Thr-Pro-Gly-Trp-Gly-Tyr-NH2) (where less than Glu = pyroglutamic acid) were determined by automated gas-phase Edman degradation of the peptides deblocked by pyroglutamate aminopeptidase and by fast atom bombardment mass spectrometry. The hormones were synthesized, and the natural and synthetic peptides exhibited identical chromatographic, spectroscopic, and biological properties. When assayed in adult face fly males, Taa-AKH and Taa-HoTH demonstrated hyperlipemic activity, in addition, Taa-HoTH also demonstrated a significant hypotrehalosemic activity.

[Tuberculous meningitis with hydrocephalus: a clinical and CT study]

Fourteen cases of tuberculous meningitis complicated by moderate or severe hydrocephalus identified by CT are reported. The accumulation and blockage of tuberculous exudate in the basic cisterns and ependymitis in the cerebrospinal drainage pathway are the important pathological features of this disease. There may be a correlation of hydrocephalus with hyponatraemia. Headache, vomiting, and impaired consciousness are common symptoms, although a few cases did not show obvious symptoms of raised intracranial tension. The study suggests a relation between the degree of hydrocephalus and the pressure on lumber puncture. If patients with impaired consciousness, especially in the chronic stage show no improvement during medical treatment, ventricular shunt may bring about remarkable improvement.

Structure and activity of the B-chain of insulin

Despentapeptide (B26-30)-insulinamide (B25) prepared by a semisynthetic procedure was found to have about 65% of the hypoglycaemic activity of natural insulin. In contrast, the binding of the modified insulin analogue to insulin specific receptors was markedly increased. The discrepancy between the loss of biological potency and the apparent increase in binding affinity for membrane receptors reveals that not all of the biological activity of insulin is regulated by the receptor-binding system. The tetrapeptidamide of the B-chain of insulin (Arg-Gly-Phe-Phe-NH2) was clearly shown to have both insulin-like and insulin-potentiating actions in vivo although it had no effect on insulin receptor function in vitro. Evidence suggests that the small peptide fragment of insulin may be internalized and acts at the post-binding site(s) of the glucose metabolic pathway in target tissues. The present data support the general concept that insulin may exert its complex molecular actions through internalized hormonal fragment as well as the transmembrane mediators generated from receptor binding.

Isolation and primary structure of a neuropeptide hormone from Heliothis zea with hypertrehalosemic and adipokinetic activities

A neuropeptide was isolated from the corpora cardiaca of the corn earworm moth Heliothis zea, and purified by sequential gradient elution in three reversed phase-high performance liquid chromatographic steps. The primary structure, pGlu-Leu-Thr-Phe-Ser-Ser-Gly-Trp-Gly-Asn-NH2 was determined by automated gas-phase Edman degradation of the peptide deblocked with pyroglutamate aminopeptidase, and confirmed by fast atom bombardment mass spectrometry. The hormone was synthesized and the natural and synthetic peptides had identical chromatographic and spectroscopic properties. Both natural and synthetic hormones caused the elevation of trehalose and lipid levels in the hemolymph of adult H. zea males.

Comparison of reaction rates in trypsin-catalysed transamidation of porcine insulin and its B29-arginine analogue

[B29-Arginine]porcine insulin was prepared from des-(B23-30)-insulin and synthetic octapeptide with the aid of trypsin. Comparison of reaction rates in trypsin-catalysed transamidation of this compound and porcine insulin with threonine ether ester showed that this reaction is determined only by conformational effects and structural features of amino acids leaving from and entering into B30, not by the structure and the pKa value of the basic amino acid in B29.

Isolation of two neuropeptides in the AKH/RPCH-family from horseflies (Diptera)

Two neuropeptides (DCCI and DCCII) in the adipokinetic/red pigment concentrating hormone-family have been isolated and purified from the corpora cardiaca of horseflies (Diptera : Tabanidae). Both peptides were purified by a sequence of three reversed phase-high performance liquid chromatographic steps. Amino acid analysis of the purified peptides indicated the following composition for DCCI: Glx(l), Gly(1), Leu(1), Phe(1), Pro(1), Thr(2) and for DCCII: Glx(1), Gly(2), Leu(1), Phe(1), Pro(1), Thr(2), and Tyr(1). Photodiode array ultraviolet spectroscopy indicated the presence of tryptophan in both DCCI and II. Both DCCI and II had red pigment concentrating hormone activity in the crab, Uca pugilator.

Iron deficiency and hearing loss. Experimental study in growing rats

Cochlear changes were studied in 141 growing rats raised on a basic iron-deficient diet for 7-100 days; 130 rats served as normal or chronic anemia controls. Electrophysiological findings showed that the incidence of an auditory threshold elevation of more than 15 dB was 31.85% in the iron-deficient rats, but it was unchanged in all the control animals. The main cochlear histopathological changes induced by iron deficiency were strial atrophy and reduction of spiral ganglion cells. It is concluded that the observed anomalies may be attributed solely to iron deficiency of the cochlear tissue.

Purification and primary structures of duck fibrinopeptides A and B

Duck fibrinopeptides A and B were purified by Dowex 50 W X 2 ion exchange resin and DEAE-Sepharose CL-6B. The complete primary structures of duck fibrinopeptides A and B were determined by manual Edman Sequence determination. The primary structure of duck fibrinopeptide A is pyr. Asp. Gly. Lys. Ser. Ser. Phe. Gln. Lys. Glu. Gly. Gly. Gly. Val. Arg., and that of duck fibrinopeptide B is Pyr. Ala. Ser. Thr. Asp. Tyr. Asp. Asp. Glu. Asp. Glu. Ser. Thr. Val. Pro. Glu. Ala. Arg.

Isolation and sequence determination of goose pancreatic polypeptide

Goose pancreatic polypeptide was isolated in crystalline form from goose pancreas. Its amino acid sequence was determined by Edman degradation and compared with avian pancreatic polypeptide.