Neurocircuitry of conditioned inhibition of analgesia: effects of amygdala, dorsal raphe, ventral medullary, and spinal cord lesions on antianalgesia in the rat

Pain inhibition (analgesia) is produced by learned danger signals and inhibited by learned safety signals (antianalgesia). Conditioned analgesia is mediated by brain-to-spinal pathways releasing spinal endogenous opiates. Spinal morphine mimics learned danger signals in producing analgesia, which is inhibited by antianalgesia. The circuitry mediating antianalgesia is unknown. These experiments demonstrate that raphe dorsalis, raphe magnus, and spinal dorsolateral funiculus lesions abolish antianalgesia. Other lesions had no effect on antianalgesia. More important, lesions that blocked development of conditioned analgesia did not block development of antianalgesia. Thus, neural circuitries mediating analgesia and antianalgesia were found to be distinct, and conditioned inhibition of analgesia was found to act by inhibiting the most distal part of the conditioned analgesia circuit, namely, the spinal cord.

Antimicrobial resistance and clinical effectiveness of co-trimoxazole versus amoxycillin for pneumonia among children in Pakistan: randomised controlled trial. Pakistan Co-trimoxazole Study Group

BACKGROUND

Co-trimoxazole is widely used in treatment of paediatric pneumonia in developing countries, but drug resistance may decrease its effectiveness. We studied the effectiveness of co-trimoxazole compared with that of amoxycillin in pneumonia therapy, and assessed the clinical impact of co-trimoxazole resistance.

METHODS

We recruited 595 children, aged 2-59 months, with non-severe or severe pneumonia (WHO criteria) diagnosed in the outpatient wards of two urban Pakistan hospitals. Patients were randomly assigned on a 2:1 basis co-trimoxazole (n=398) or amoxycillin (n=197) in standard WHO doses and dosing schedules, and were monitored in study wards. The primary outcome was inpatient therapy failure (clinical criteria) or clinical evidence of pneumonia at outpatient follow-up examination.

FINDINGS

There were 92 (23%) therapy failures in the co-trimoxazole group and 30 (15%) in the amoxycillin group (p=0.03)-26 (13%) versus 12 (12%) among children with non-severe pneumonia (p=0.856) and 66 (33%) versus 18 (18%) among those with severe pneumonia (p=0.009). For patients with severe pneumonia, age under 1 year (p=0.056) and positive chest radiographs (p=0.005) also predicted therapy failure. There was no significant association between antimicrobial minimum inhibitory concentration and outcome among bacteraemic children treated with co-trimoxazole.

INTERPRETATION

Co-trimoxazole provided effective therapy in non-severe pneumonia. For severe, life-threatening pneumonia, however, co-trimoxazole is less likely than amoxycillin to be effective.

Invasive group A streptococcal disease in metropolitan Atlanta: a population-based assessment

Active, population-based surveillance for invasive group A streptococcal (GAS) disease was conducted in laboratories in metropolitan Atlanta from 1 January 1994 through 30 June 1995. Clinical and laboratory records were reviewed and isolates characterized. One hundred and eighty-three cases of invasive GAS disease were identified (annual incidence, 5.2 cases/100,000). The incidence was highest among blacks (9.7/100,000 per year; relative risk (RR), 1.92; confidence interval (CI), 1.69-2.19; P < .0001) and the elderly, particularly nursing home residents (RR, 13.66; CI, 7.07-26.40; P < .0001). The mean age of patients was 41.3 years (range, 0-95 years). Skin and soft-tissue infections were most common. Mortality was 14.4%; risk of death was significantly higher for patients with streptococcal toxic shock syndrome (STSS) (RR, 9.73; CI, 3.34-29; P = .0008) and individuals infected with M-type 1 (RR, 7.40; CI, 1.5-16; P = .0084). Fourteen percent of invasive GAS infections were STSS and 3% were necrotizing fasciitis. Invasive GAS disease was associated with varicella infection in children (RR, 12.19; CI, 5.58-26.62; P < .0001). M (or emm) types included M1 (16%), M12 (12%), and M3 (11%). Continued study of GAS disease is essential to further define risk factors and risk of secondary cases and to develop effective prevention strategies.

Rapid hematopoietic recovery after multicycle high-dose chemotherapy: enhancement of filgrastim-induced progenitor-cell mobilization by recombinant human stem-cell factor

PURPOSE

To assess the mobilization potential and safety of recombinant human stem-cell factor (SCF) when coadministered with filgrastim to untreated women with poor-prognosis breast cancer.

PATIENTS AND METHODS

Eligible women had breast cancer with 10 or more positive axillary nodes, or estrogen receptor-negative tumor with 4 positive nodes, or stage III disease. Patients were randomized to receive SCF plus filgrastim or filgrastim alone. Filgrastim 12 microg/kg daily was administered for 6 days by continuous subcutaneous infusion. SCF was administered by daily subcutaneous injection at 5, 10, or 15 microg/kg concurrent with filgrastim for 7 days, or 10 microg/kg daily starting 3 days before filgrastim for a total of 10 days (SCF pretreatment). Apheresis was performed on days 5, 6, and 7 of filgrastim administration. Patients then had three cycles of epirubicin 200 mg/m2 and cyclophosphamide 4 g/m2 every 28 days, each supported by one third of the apheresis product.

RESULTS

Sixty-two women were treated. Greater yields occurred in patients who received SCF 10 microg/kg daily plus filgastim than those who received filgrastim alone (P=.013 for CD34+ cells; P=.07 for granulocyte-macrophage colony-forming cells [GM-CFCs]). The difference was more marked with SCF-pretreatment than concurrent SCF. Fewer aphereses were required to reach the predetermined target of peripheral-blood progenitor/stem cells (PBPCs) in women who received SCF. SCF was generally well tolerated. Hematologic recovery was rapid after each of the three cycles of chemotherapy. There was no difference in recovery between the different treatment groups.

CONCLUSION

Mobilization of PBPCs by filgrastim is significantly enhanced by coadministration of SCF, and commencing SCF before filgrastim can optimize this effect. SCF has the potential to reduce the number of aphereses required to collect a target number of PBPCs.

Opsonic antibodies to the surface M protein of group A streptococci in pooled normal immunoglobulins (IVIG): potential impact on the clinical efficacy of IVIG therapy for severe invasive group A streptococcal infections

The surface M protein of group A streptococci (GAS) is one of the major virulence factors for this pathogen. Antibodies to the M protein can facilitate opsonophagocytosis by phagocytic cells present in human blood. We investigated whether pooled normal immunoglobulin G (IVIG) contains antibodies that can opsonize and enhance the phagocytosis of type M1 strains of GAS and whether the levels of these antibodies vary for different IVIG preparations. We focused on the presence of anti-M1 antibodies because the M1T1 serotype accounts for the majority of recent invasive GAS clinical isolates in our surveillance studies. The level of anti-M1 antibodies in three commercial IVIG preparations was determined by enzyme-linked immunosorbent assay (ELISA), and the opsonic activity of these antibodies was determined by neutrophil-mediated opsonophagocytosis of a representative M1T1 isolate. High levels of opsonic anti-M1 antibodies were found in all IVIG preparations tested, and there was a good correlation between ELISA titers and opsonophagocytic activity. However, there was no significant difference in the levels of opsonic anti-M1 antibodies among the various IVIG preparations or lots tested. Adsorption of IVIG with M1T1 bacteria removed the anti-M1 opsonic activity, while the level of anti-M3 opsonophagocytosis was unchanged. Plasma was obtained from seven patients with streptococcal toxic shock syndrome who received IVIG therapy, and the level of anti-M1 antibodies was assessed before and after IVIG administration. A significant increase in the level of type M1-specific antibodies was found in the plasma of all patients who received IVIG therapy (P < 0.006). The results reveal another potential mechanism by which IVIG can ameliorate severe invasive group A streptococcal infections.

Epidemic of pediatric deaths from acute renal failure caused by diethylene glycol poisoning. Acute Renal Failure Investigation Team

CONTEXT

Contaminated pharmaceutical products can result in substantial morbidity and mortality and should be included in the differential diagnosis of deaths of unknown origin.

OBJECTIVE

To investigate an outbreak of deaths among children from acute renal failure in Haiti to determine the etiology and institute control measures.

DESIGN

Case-control study, cohort study, and laboratory toxicologic evaluation.

SETTING

Pediatric population of Haiti.

PARTICIPANTS

Cases were defined as Haitian residents younger than 18 years with idiopathic anuria or severe oliguria for 24 hours or longer. Febrile hospitalized children without renal failure were enrolled as control subjects.

MAIN OUTCOME MEASURE

The odds of exposure to suspected etiologic agents among cases and controls.

RESULTS

We identified 109 cases of acute renal failure among children. The clinical syndrome included renal failure, hepatitis, pancreatitis, central nervous system impairment, coma, and death. Of 87 patients with follow-up information who remained in Haiti for treatment, 85 (98%) died; 3 (27%) of 11 patients transported to the United States for intensive care unit management died before hospital discharge. A locally manufactured acetaminophen syrup was highly associated with disease (odds ratio, 52.7; 95% confidence interval, 15.2-197.2). Diethylene glycol (DEG) was found in patients' bottles in a median concentration of 14.4%. The median estimated toxic dose of DEG was 1.34 mL/kg (range, 0.22-4.42 mL/kg). Glycerin, a raw material imported to Haiti and used in the acetaminophen formulation, was contaminated with 24% DEG.

CONCLUSIONS

An epidemic of severe systemic toxicity and deaths from DEG-contaminated acetaminophen syrup occurred in Haiti. Good manufacturing practice regulations should be used by all pharmaceutical manufacturers to prevent such tragedies.

Neurocircuitry of conditioned inhibition of analgesia: effects of amygdala, dorsal raphe, ventral medullary, and spinal cord lesions on antianalgesia in the rat

Pain inhibition (analgesia) is produced by learned danger signals and inhibited by learned safety signals (antianalgesia). Conditioned analgesia is mediated by brain-to-spinal pathways releasing spinal endogenous opiates. Spinal morphine mimics learned danger signals in producing analgesia, which is inhibited by antianalgesia. The circuitry mediating antianalgesia is unknown. These experiments demonstrate that raphe dorsalis, raphe magnus, and spinal dorsolateral funiculus lesions abolish antianalgesia. Other lesions had no effect on antianalgesia. More important, lesions that blocked development of conditioned analgesia did not block development of antianalgesia. Thus, neural circuitries mediating analgesia and antianalgesia were found to be distinct, and conditioned inhibition of analgesia was found to act by inhibiting the most distal part of the conditioned analgesia circuit, namely, the spinal cord.

A streptococcal score card revisited

OBJECTIVE

To evaluate the utility of a simple scoring system as a predictor of obtaining a positive throat culture for group A streptococci (GAS).

DESIGN

Prospective descriptive study. Scores were assigned prior to the availability of the results of throat cultures.

SETTING

Emergency department and walk-in clinic of the Children's Hospital of Pittsburgh.

PATIENTS

Patients were 365 children between the ages of two and 16 years with acute onset of sore throat and a history of or documentation of fever within the preceding 24 hours.

INTERVENTIONS

A streptococcal score was assigned on the basis of a 6-point schema in which the features were 1) age; 2) season; 3) temperature of at least 38.3 degrees C; 4) adenopathy; 5) pharyngeal erythema, edema, or exudate; and 6) no symptoms of a viral upper respiratory infection (conjunctivitis, rhinorrhea, or cough). A throat culture was performed for the isolation of GAS.

MAIN OUTCOME MEASURE

Positive predictive value of the streptococcal score in identifying children with a positive throat culture for GAS.

RESULTS

A score of 5 or 6 predicted a positive culture for GAS in 59 and 75% of children, respectively. In patients with evidence of acute pharyngitis, the combination of age between five and 15 years, fever and absence of upper respiratory symptoms predicted a positive culture for GAS in 72% of patients.

CONCLUSIONS

The score can be used to predict the likelihood that a throat culture will be positive for GAS.

Synthesis, activity, and structure--activity relationship studies of novel cationic lipids for DNA transfer

We have designed and synthesized original cationic lipids for gene delivery. A synthetic method on solid support allowed easy access to unsymmetrically monofunctionalized polyamine building blocks of variable geometries. These polyamine building blocks were introduced into cationic lipids. To optimize the transfection efficiency in the novel series, we have carried out structure-activity relationship studies by introduction of variable-length lipids, of variable-length linkers between lipid and cationic moiety, and of substituted linkers. We introduce the concept of using the linkers within cationic lipids molecules as carriers of side groups harboring various functionalities (side chain entity), as assessed by the introduction of a library composed of cationic entities, additional lipid chains, targeting groups, and finally the molecular probes rhodamine and biotin for cellular traffic studies. The transfection activity of the products was assayed in vitro on Hela carcinoma, on NIH3T3, and on CV1 fibroblasts and in vivo on the Lewis Lung carcinoma model. Products from the series displayed high transfection activities. Results indicated that the introduction of a targeting side chain moiety into the cationic lipid is permitted. A primary physicochemical characterization of the DNA/lipid complexes was demonstrated with this leading compound. Selected products from the series are currently being developed for preclinical studies, and the labeled lipopolyamines can be used to study the intracellular traffic of DNA/cationic lipid complexes.

Sulpiride augmentation in people with schizophrenia partially responsive to clozapine. A double-blind, placebo-controlled study

BACKGROUND

We hypothesised that a combined regimen of clozapine, a relatively weak D2-dopaminergic antagonist, and sulpiride, a selective D2 blocker, would demonstrate a greater antipsychotic efficacy by enhancing the D2 blockade of clozapine.

METHOD

Twenty-eight people with schizophrenia, previously unresponsive to typical antipsychotics and only partially responsive to current treatment with clozapine, received, double-blind, 600 mg/day sulpiride or placebo, in addition to an ongoing clozapine treatment. The clinical status was evaluated before, during, and at the end of 10 weeks of sulpiride addition using the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive Symptoms (SAPS), Scale for the Assessment of Negative Symptoms, and Hamilton Rating Scale for Depression.

RESULTS

The clozapine-sulpiride group exhibited substantially greater and significant improvements in positive and negative psychotic symptoms. About half of them, characterised by a younger age and lower baseline SAPS scores, had a mean reduction of 42.4 and 50.4% in their BPRS and SAPS scores, respectively.

CONCLUSIONS

A subgroup of patients with chronic schizophrenia may substantially benefit from sulpiride addition to clozapine.

Characterization of sodium and chloride conductances in preneoplastic and neoplastic murine colonocytes

Glucocorticoids, such as dexamethasone, induce amiloride-sensitive Na+ conductances in rat distal colon epithelium. The activity of these conductances diminishes from the surface to the base of the crypt whereas cAMP-stimulated Cl- secretion decreases from the crypt base to the surface. These gradients are likely to be perturbed during carcinogenesis. We therefore determined the magnitude of Na+ and Cl- conductances in colonocytes isolated from normal and carcinogen-treated rats. Colon carcinogenesis was induced by injection of dimethylhydrazine (DMH) (18 mg/kg) for 5 weeks. Before sacrifice animals were treated for 3 days with dexamethasone. Colonocyte populations from the surface to the crypt base (C1-C5) were harvested from the distal colon by a Ca2+-chelating procedure. The activity of Na+ conductances was determined by uptake of 22Na+ by surface and crypt colonocyte populations and by membrane vesicles in the presence and absence of 10 microM amiloride. In control rats Na+ conductance was highest in surface colonocytes and absent in the crypt base. As early as 2 weeks after initiation of DMH treatment amiloride-inhibited Na+ uptake was virtually absent in the upper crypt. Transcriptional assessment of the alpha-, beta- and gamma-subunits that constitute the epithelial Na+ channel revealed that DMH treatment reduces the expression of beta-subunit mRNA. We then examined 36Cl- efflux from isolated colonocytes of normal and carcinogen-treated rats in response to forskolin (0.01 mM). Forskolin induced a marked rise in cAMP in lower crypt cells concomitant with a significant stimulation of 36Cl- efflux. Intracellular cAMP increased in upper crypt cells in response to forskolin without an increase in 36Cl- efflux. By contrast, upper crypt colonocytes from DMH-treated rats showed forskolin-stimulated efflux beginning 4 weeks after initiation of treatment. We conclude that induction of Na+ conductances by glucocorticoids is inhibited during the early stages of chemical carcinogenesis due to lack of induction of the beta-subunit of the channel. By contrast, Cl- transport is stimulated both in surface and lower crypt cell compartments during different stages of chemical carcinogenesis.

Computerized measurement of the three-dimensional distribution of optic disc pallor

PURPOSE

To describe a method which provides quantitative measurements of the surface area of pallor in each quadrant of the three-dimensional optic cup, using photogrammetric measurements from simultaneous stereophotographs and computerized image analysis.

METHODS

Simultaneous stereophotographs of one normal subject and two subjects with primary open angle glaucoma were digitized and analyzed for depth measurements. The boundaries of the optic disc, optic cup and region of pallor were identified. Pallor/disc and pallor/cup ratios were subsequently calculated for the superior, temporal, inferior and nasal walls.

RESULTS

A digitized photograph and a Laplacian-filtered image were obtained for each eye to be studied. After processing each stereo pair through a similarity sequential detection-based algorithm, depth measurements are represented as a grey scale image, a contour plot, and a wire mesh, with the boundaries of the optic disc, optic cup and pallor superimposed. Ratios are given of the surface area of pallor to the surface area of the disc and the surface area of pallor to the surface area of the cup, by quadrant.

CONCLUSIONS

Determination of surface area of pallor to cup may be useful in detecting early visual field loss in glaucoma and neurological disease.

Patients' satisfaction when denied authorization for emergency department care by their managed care plan

We conducted a survey of managed care plan (MCP) patients who presented to the emergency department (ED) but were denied insurance authorization during a 3-month period. Patients were identified by triage or registration records, contacted by telephone after their visit, and surveyed regarding their satisfaction with the ED and MCP, follow-up care, and future behavior. We surveyed 72 (73.4%) of 98 subjects who were denied authorization. Forty-nine (68.1%) were redirected to a clinic or primary physician, 14 (19.4%) to an urgent care or other ED, and 9 (12.5%) were given no follow-up. Fifty-five respondents (76.4%) stated they had followed-up as directed, but 34 (47.2%) felt the delay had a negative impact. Thirty-nine (54.2%) were dissatisfied with their MCP. If their problems were to recur, 27 (37.5%) stated they would go to a clinic or call their MCP, but 34 (47.2%) would return to the ED. Many patients who are denied authorization are dissatisfied with their MCP and will return to the ED in the future, despite previous denials.

Enhanced ocular hypotensive response to epinephrine in rabbits with prior dexamethasone treatment

The purpose of this study was to determine glucocorticoid modulation of ocular pressure to epinephrine applied topically to rabbit eyes that were pretreated with dexamethasone. Rabbit eyes were pretreated with five applications of topical 0.07% dexamethasone (0.1% dexamethasone phosphate) or saline drops, administered at ten minute intervals. The eyes were then treated with epinephrine bitartrate drops at concentrations of free base epinephrine of 1.1%, 0.27%, 0.05%, 0.027%, 0.005% or 0.0005%. An additional group of rabbits received dexamethasone pretreatment only. Intraocular pressure (IOP) was measured for the next four hours. Enhanced lowering of intraocular pressure was observed with dexamethasone pretreatment. Rabbits receiving the smaller dose of epinephrine with dexamethasone had the largest decrease in IOP at 135 minutes after instillation of the epinephrine drops (0.005% epinephrine, mean difference +/- standard error of mean = 5.4 +/- 1.1 mmHg). Similarly, the duration of significant decrease of the IOP was prolonged in the groups receiving the lower concentrations of epinephrine (0.005% epinephrine, 255 minutes after administration of epinephrine). The synergism between glucocorticoids and adrenergic agonists in lowering IOP may be potentially useful in the therapy of ocular hypertension and glaucoma.

Reversal of spinal cord non-opiate analgesia by conditioned anti-analgesia in the rat

The spinal cord contains endogenous substances (such as cholecystokinin, FMRFamide, etc.) that can block the analgesic effects of opiates. Anti-opiate actions have been most commonly studied by exogenous administration of receptor agonists and receptor antagonists of these substances. However, we have recently demonstrated that anti-analgesia can be brought under environmental control through Pavlovian conditioning. Whereas analgesia can be conditioned to signals for danger, anti-analgesia can be conditioned to signals for safety. Using this paradigm, we have previously demonstrated that conditioned anti-analgesia can reverse a variety of opiate analgesic states, including those produced by conditioned danger signals, systemic morphine, and intrathecal mu- and delta-opiate receptor agonists. These data raise the question of the generality of anti-analgesia actions. The present series of experiments examined the ability of conditioned anti-analgesia to affect non-opiate analgesic states induced by spinal delivery of GABA(A), GABA(B), 5HT2 + 5HT1, and 5HT3 receptor agonists. While conditioned anti-analgesia had no effect on GABA(A) or 5HT2 + 5HT1 non-opiate analgesias, conditioned anti-analgesia completely blocked GABA(B) and 5HT3 non-opiate analgesias. These findings clearly demonstrate that conditioned anti-analgesia can powerfully modulate non-opiate as well as opiate analgesias and bring into question whether putative anti-opiate neuroactive substances may have broader actions than previously suggested.

Population-based surveillance for group A streptococcal necrotizing fasciitis: Clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Ontario Group A Streptococcal Study

PURPOSE

To determine the incidence of group A streptococcal necrotizing fasciitis in Ontario, Canada, and to describe the clinical features, outcome, and microbiologic characteristics of this infection.

PATIENTS AND METHODS

Prospective, population-based surveillance for invasive group A streptococcal infections was conducted in Ontario from November 1991 to May 1995. All 77 patients meeting clinical and/or histopathologic criteria for streptococcal necrotizing fasciitis were included. Demographic and clinical information was obtained by patient interviews and chart review. Group A streptococci were characterized by M-protein and T-agglutination typing, and polymerase chain reaction (PCR) detection of streptococcal pyrogenic exotoxin genes A and C (speA; speC).

RESULTS

The incidence of group A streptococcal necrotizing fasciitis increased during the study from 0.085 per 100,000 population in the first year to 0.40 per 100,000 population in the last year (P < 0.001). The median age of cases was 57.5 years and the rate of disease increased with increasing age. Seventy-nine percent of cases were community-acquired, 11% were nosocomial, and 10% were acquired in a nursing home. Forty-seven percent of cases were associated with the presence of streptococcal toxic shock syndrome (Strep TSS) and 46% were bacteremic. Thirty-four percent of cases died and mortality was correlated with increasing age (P = 0.006), presence of hypotension (P = 0.01), and bacteremia (P = 0.03). The most common streptococcal serotypes were M1 (35%) and M3 (25%). Forty-one percent of strains possessed the speA gene and 30% the speC gene. Outcome was not correlated with M-type or the presence of spe genes.

CONCLUSIONS

The incidence of necrotizing fasciitis caused by group A streptococcus increased in Ontario between 1992 and 1995. Elderly individuals were more likely to acquire the disease and to die from it. Mortality because of streptococcal necrotizing fasciitis was also associated with the presence of hypotension, Strep TSS, or bacteremia, but not with M-type or the presence of pyrogenic exotoxin genes.

Population-based surveillance for group A streptococcal necrotizing fasciitis: Clinical features, prognostic indicators, and microbiologic analysis of seventy-seven cases. Ontario Group A Streptococcal Study

PURPOSE

To determine the incidence of group A streptococcal necrotizing fasciitis in Ontario, Canada, and to describe the clinical features, outcome, and microbiologic characteristics of this infection.

PATIENTS AND METHODS

Prospective, population-based surveillance for invasive group A streptococcal infections was conducted in Ontario from November 1991 to May 1995. All 77 patients meeting clinical and/or histopathologic criteria for streptococcal necrotizing fasciitis were included. Demographic and clinical information was obtained by patient interviews and chart review. Group A streptococci were characterized by M-protein and T-agglutination typing, and polymerase chain reaction (PCR) detection of streptococcal pyrogenic exotoxin genes A and C (speA; speC).

RESULTS

The incidence of group A streptococcal necrotizing fasciitis increased during the study from 0.085 per 100,000 population in the first year to 0.40 per 100,000 population in the last year (P < 0.001). The median age of cases was 57.5 years and the rate of disease increased with increasing age. Seventy-nine percent of cases were community-acquired, 11% were nosocomial, and 10% were acquired in a nursing home. Forty-seven percent of cases were associated with the presence of streptococcal toxic shock syndrome (Strep TSS) and 46% were bacteremic. Thirty-four percent of cases died and mortality was correlated with increasing age (P = 0.006), presence of hypotension (P = 0.01), and bacteremia (P = 0.03). The most common streptococcal serotypes were M1 (35%) and M3 (25%). Forty-one percent of strains possessed the speA gene and 30% the speC gene. Outcome was not correlated with M-type or the presence of spe genes.

CONCLUSIONS

The incidence of necrotizing fasciitis caused by group A streptococcus increased in Ontario between 1992 and 1995. Elderly individuals were more likely to acquire the disease and to die from it. Mortality because of streptococcal necrotizing fasciitis was also associated with the presence of hypotension, Strep TSS, or bacteremia, but not with M-type or the presence of pyrogenic exotoxin genes.

Survey of emm gene sequences and T-antigen types from systemic Streptococcus pyogenes infection isolates collected in San Francisco, California; Atlanta, Georgia; and Connecticut in 1994 and 1995

The variable 5' emm (M-protein gene) sequences and T-antigen types were determined from 340 systemic group A streptococcal (GAS) isolates taken from hospitalized patients in San Francisco, Calif.; Atlanta, Ga.; and Connecticut in 1994 and 1995. Eighty percent of these isolates had emm sequences and T-antigen types in agreement with previously recorded M- and T-antigen associations. Most of the remaining strains either were T nontypeable (11%) or contained emm genes encoding M proteins for which T-antigen associations have not been made (6%). One newly encountered emm gene, designated ST2974, from each of 13 isolates had the T type 8/25/Imp19. Another new emm gene, ST2967, from 8 of 11 isolates was T nontypeable. Six other unique emm gene sequences from seven isolates were encountered. Sequencing of the variable region of the emm gene of GAS isolates (emm typing) is effective for surveying the sequence variability of the M virulence protein, and combined with T typing, emm typing is useful for monitoring GAS strain diversity.

Ability of single-site mutants of citrate synthase to catalyze proton transfer from the methyl group of dethiaacetyl-coenzyme A, a non-thioester substrate analog

The catalytic strategies of enzymes (such as citrate synthase) whose reactions require the abstraction of the alpha-proton of a carbon acid remain elusive. Citrate synthase readily catalyzes solvent proton exchange of the methyl protons of dethiaacetyl-coenzyme A, a sulfur-less, ketone analog of acetyl-coenzyme A, in its ternary complex with oxaloacetate. Because no further reaction occurs with this analog, it provides a uniquely simple probe of the roles of active site interactions on carbon acid proton transfer catalysis. In view of the high reactivity of the analog for proton transfer to the active site base, its failure to further condense with oxaloacetate to form a sulfur-less analog of citryl-coenzyme A was unexpected, although we offer several possible explanations. We have measured the rate constants for exchange, k(exch), at saturating concentrations of the analog for six citrate synthase mutants with single changes in active site residues. Comparisons between the values of k(exch) are straightforward in two limits. If the rate of exchange of the transferred proton with solvent protons is rapid, then k(exch) equals the forward rate constant for proton transfer, and k(exch) values for different mutants compare directly the rate constants for proton transfer. If the exchange of the transferred proton with protons in the bulk solution is the slow step and the equilibrium constant for proton transfer is unfavorable (as is likely), then k(exch) equals the product of the equilibrium constant for proton transfer and the rate constant for exchange of the transferred proton with bulk solvent. If that exchange rate with bulk solution remains constant for a series of mutant enzymes, then k(exch) values compare the equilibrium constants for proton transfer. The importance of the acetyl-CoA site residues, H274 and D375, is confirmed with D375 again implicated as the active site base. The results with the series of oxaloacetate site mutants, H320X, strongly suggest that activation of the first substrate, oxaloacetate, through carbonyl bond polarization, not just oxaloacetate binding in the active site, is required for the enzyme to efficiently catalyze proton transfer from the methyl group of the second substrate.

Enhanced acute ocular hypotensive response to timolol with dexamethasone treatment

PURPOSE

This study was conducted to determine whether low doses of dexamethasone can enhance the lowering of ocular pressure by low doses of timolol.

PATIENTS AND METHODS

In 12 patients with untreated ocular hypertension and similar intraocular pressures in each eye, one eye was randomly selected in a masked manner for pretreatment with three applications of topical 0.01% dexamethasone sodium phosphate drops prepared in artificial tears. The other eye was treated with three applications of drops of artificial tears alone. Both eyes were then treated with 0.01% timolol maleate drops. Ocular pressure was measured for the next 100 minutes at 20-minute intervals. The study was done in an outpatient office. Twelve untreated ocular hypertensive patients participated in this study.

RESULTS

When compared with eyes treated with timolol drops alone, eyes pretreated with dexamethasone drops showed a significantly greater decrease in ocular pressure (mean +/- SD); the maximal decrease in 12 dexamethasone-treated patients was 3.5 +/- 1.9 mm Hg (15.9% from baseline). Six dexamethasone-treated patients had a response of 4.0 to 6.0 mm Hg, whereas three showed responses < 4 and > 2 mm Hg with three < or = 2 mm Hg.

CONCLUSIONS

This synergistic effect of timolol with dexamethasone on lowering of ocular pressure offers a potential therapeutic use in ocular hypertension and glaucoma.

Resistant pneumococci: protecting patients through judicious use of antibiotics

Increasing resistance to antimicrobial agents has occurred among many pathogens, but the emergence of resistant Streptococcus pneumoniae will have the greatest impact on the practice of outpatient medicine. Consequences of resistance include complicated management of acute otitis media and meningitis treatment failures. Pneumococci have acquired resistance to penicillin, third-generation cephalosporins and other antibiotics at an alarming rate; in some areas, 25 percent of isolates are nonsusceptible to penicillin. In areas with high resistance rates, the addition of vancomycin to cefotaxime or ceftriaxone is warranted for empiric treatment of bacterial meningitis. Changes in empiric therapy for pneumonia, bacteremia and otitis media may eventually be necessary. Previous antibiotic use is a risk factor for invasive disease with resistant pneumococci. Patients may be best protected by avoiding unnecessary use of antibiotics. Patient education materials as well as recommendations for avoiding the use of antibiotics for some upper respiratory tract infections are currently being developed to help physicians achieve this goal.

Gastrin levels in colorectal cancer

Our objective was to determine whether colorectal cancer tissue synthesizes and secretes biologically active gastrins resulting in a rise of gastrin levels in patients with adenocarcinoma of the colon. Blood samples for gastrin determination were taken from the artery feeding, and from the vein draining colon tumors, from a vein draining an uninvolved colon segment and from a peripheral vein. Tissue gastrin levels were measured in tumor tissues and normal mucosa taken by colonoscopic biopsy from colon cancer patients and healthy controls. The setting was a university hospital research laboratory. We had seventeen patients with colorectal cancer and 23 controls. No significant difference was found in peripheral venous blood gastrin levels between the cancer and the control groups. Serum gastrin concentration was not significantly different in the arterial blood which supplied the tumor area, the venous blood draining the tumor, the "uninvolved" mucosa or the control normal epithelium. Cancer tissue gastrin levels were lower than those measured in biopsies of uninvolved mucosa from cancer patients and normal controls. The present results show no rise of gastrin blood levels in patients with colon cancer, nor any evidence of gastrin-increased synthesis by the tumors.

Emergence of antibody to capsular polysaccharides of Streptococcus pneumoniae during outbreaks of pneumonia: association with nasopharyngeal colonization

Antibody to pneumococcal capsular polysaccharides (PPS) of Streptococcus pneumoniae plays a major role in protecting the host against pneumococcal infection. A variable proportion of healthy adults have antibody to PPS, often in the absence of recognized pneumococcal infection. To determine whether exposure to pneumococci or colonization by pneumococci, or both, stimulates the emergence of antibody to PPS, we studied outbreaks of pneumonia at two military camps. Of the men who were present at a military training camp during an outbreak of pneumonia due to S. pneumoniae serotype 1 but who did not develop pneumonia, 27.8% had IgG antibody to PPS 1, whereas only 3.6% of controls had this antibody. In another outbreak caused by S. pneumoniae serotypes 7F and 8, 35.9% of asymptomatic soldiers who had nasopharyngeal colonization by one of these strains had antibody to the relevant PPS, and another 30.8% who originally did not have antibody developed it within 30 days; thus, 66.7% of these soldiers had antibody to the relevant PPS. These data show that serotype-specific antibody promptly appears following exposure to an outbreak of pneumococcal pneumonia and is probably mediated through acquisition of nasopharyngeal pneumococcal carriage.

House dust mite allergens in Saudi Arabia: Regional variations and immune response

In order to assess the causative extrinsic allergic factor(s) in school-age children diagnosed as having bronchial asthma and allergic rhinitis, and to qualitatively and quantitatively evaluate the presence of house dust mites (HDMs) in the homes of these children in Saudi Arabia, a study analyzing mite contents in 165 samples collected from patientsâ indoor environment was conducted. The dust samples were collected from four regions of Saudi Arabia, showing variation in their geography and climate. Immunochemical assays were performed using ALK reagents by ELISA technique. A total of 462 children were also tested using skin prick test (SPT) method for IgE-mediated reactions to HDMs. The samples from the Central dry region revealed a very low amount of the potent house dust mites (Dermatophagoides pteronyssinus and D. farinae, the two dominant species in various parts of the world). The samples from the Southern mountainous region contained a very high concentration of Der p I (84,000 ng/g of dust), while the Western coastal region showed a high concentration of Der f I (up to 22,000 ng/g). The mid-Western agricultural region did not exhibit any significant level of either Der p I or Der f I. The maximum level of D. pteronyssinus detected in the Central dry region was 106 ng/g of dust. The data exhibit both qualitative and quantitative variations of HDMs in the three regions and may be attributed to variation in geography and climate, particularly humidity of the regions, which vary significantly. Riyadh in the Central region is considered to have low humidity (<40%), while humidity in the Western coastal region, Jeddah, and the Southern region of Abha is comparatively higher, which helps house dust mites thrive. SPT results in these regions with house dust mite allergens (in addition to other common inhalant allergens) also revealed a considerable number of IgE-mediated reactions, consistent with the frequency of house dust mites in the region. Though more data are being accumulated on the subject to conduct a statistical comparison and more skin tests are underway in the Southern region, the study suggests the presence of at least two HDMs as well as qualitative diversity and quantitative variation of house dust mites in Saudi Arabia. The study also indicates, with a considerable number of IgE-mediated reactions, the possible influence of mites in the allergic manifestations of many patients, which is not only common, but increasing in parts of the country.

Handwashing and glove use in a long-term-care facility

OBJECTIVES

To determine glove use and handwashing practices, the factors associated with infection control practices, and the frequency of potential microbial transmission in a long-term-care facility (LTCF).

DESIGN

Observational study of 230 staff-resident interactions in an LTCF. We recorded resident characteristics, type of activity, staff credentials, and movements of the staff member's hands, then used the LTCF's guidelines to judge appropriateness of glove use and handwashing.

SETTING

255-bed, university-based LTCF in Baltimore, Maryland.

PARTICIPANTS

A systematic sample of staff-resident interactions.

RESULTS

Gloves were worn in 139 (82%) of 170 interactions when indicated, but changed appropriately in only 1 (16%) of 132. Hands were washed when needed before an interaction in 27%, during an interaction in 0%, and after an interaction in 63%. Gloves were less likely to be used when caring for residents with gastrostomy tubes compared with other residents (relative risk, 0.85; 95% confidence interval, 0.73-0.98). Guidelines were followed more frequently during wound care than during other activities. Microbial transmission potentially could have occurred in 158 (82%) of 193 evaluable interactions.

CONCLUSIONS

We documented marked deficiencies in glove and handwashing, demonstrated the possible impact of these deficiencies, and identified factors associated with inadequate handwashing and glove use. This information can be used in future educational and research efforts to improve infection control practices.

Evaluation of clinical signs to diagnose anaemia in Uganda and Bangladesh, in areas with and without malaria

The object of this study was to assess the ability of pallor and other clinical signs, including those in the Integrated Management of Childhood Illness (IMCI) guidelines developed by WHO and UNICEF, to identify severe anaemia and some anaemia in developing country settings with and without malaria. A total of 1226 and 668 children aged 2 months to 5 years were prospectively sampled from patients presenting at, respectively, a district hospital in rural Uganda and a children's hospital in Dhaka, Bangladesh. The study physicians obtained a standardized history and carried out a physical examination that included pallor, signs of respiratory distress, and the remaining IMCI referral signs. The haematocrit or haemoglobin level was determined in all children with conjunctival or palmar pallor, and in a sample of the rest. Children with a blood level measurement and assessment of pallor at both sites were included in the anaemia analysis. Using the haematocrit or haemoglobin level as the reference standard, the correctness of assessments using severe and some pallor and other clinical signs in classifying severe and some anaemia was determined. While the full IMCI process would have referred most of the children in Uganda and nearly all the children in Bangladesh with severe anaemia to hospital, few would have received a diagnosis of severe anaemia. Severe palmar and conjunctival pallor, individually and together, had 10-50% sensitivity and 99% specificity for severe anaemia; the addition of grunting increased the sensitivity to 37-80% while maintaining a reasonable positive predictive value. Palmar pallor did not work as well as conjunctival pallor in Bangladesh for the detection for severe or some anaemia. Combining "conjunctival or palmar pallor" detected 71-87% of moderate anaemia and half or more of mild anaemia. About half the children with no anaemia were incorrectly classified as having "moderate or mild" anaemia. Anaemia was more easily diagnosed in Uganda in children with malaria. Our results show that simple clinical signs can correctly classify the anaemia status of most children. Grunting may serve as a useful adjunct to pallor in the diagnosis of severe anaemia. Conjunctival pallor should be added to the IMCI anaemia box, or the guidelines need to be adapted in regions where palmar pallor may not readily be detected.

Identifying sick children requiring referral to hospital in Bangladesh

The object of this study was to evaluate and improve the guidelines for the Integrated Management of Childhood Illness (IMCI) with respect to identifying young infants and children requiring referral to hospital in an area of low malaria prevalence. A total of 234 young infants (aged 1 week to 2 months) and 668 children (aged 2 months to 5 years) were prospectively sampled from patients presenting at a children's hospital in Dhaka, Bangladesh. The study paediatricians obtained a standardized history and carried out a physical examination, including items in the IMCI guidelines developed by WHO and UNICEF. The paediatricians made a provisional diagnosis and judged whether each patient needed hospital admission. Using the paediatrician's assessment of a need for admission as the standard, the sensitivity and specificity of the current and modified IMCI guidelines for correctly referring patients to hospital were examined. The IMCI's sensitivity for a paediatrician's assessment in favour of hospital admission was 84% (95% confidence interval (CI): 75-90) for young infants and 86% (95% CI: 81-90) for children, and the specificity was, respectively, 54% (95% CI: 45-63) and 64% (95% CI: 59-69). One fourth or more in each group had a provisional diagnosis of pneumonia, and the IMCI's specificity was increased without lowering sensitivity by modifying the respiratory signs calling for referral. These results show that the IMCI has good sensitivity for correctly referring young infants and children requiring hospital admission in a developing country setting with a low prevalence of malaria. The guidelines' moderate specificity will result in considerable over-referral of patients not needing admission, thereby decreasing opportunities for successful treatment of patients at first-level health facilities. The impact of the IMCI guidelines on children's health and the health care system must be judged in the light of current treatment practices, health outcomes and referral patterns.

Effects of the carcinogen dimethylhydrazine (DMH) on the function of rat colonic crypts

Rats injected with dimethylhydrazine for 5 weeks (DMH, 40 mg/kg body weight) invariably develop colonic cancer after a latency of some 10-14 weeks. Preliminary studies have suggested that Na+ absorption by surface colonic crypt cells is attenuated in the preneoplastic period (8-12 weeks after the first injection of DMH). The present study of glucocorticoid-treated (dexamethasone 6 mg/kg body weight, s.c. 3 days or triamcinolone 30 mg/kg body weight, s.c. 3 days) rats was undertaken to examine the ion transport properties of rat distal colon during this period in more detail. Ussing chamber studies of the distal colon and whole-cell patch-clamp measurements in surface cells, mid-crypt cells and crypt-base cells obtained from isolated crypts were performed. In Ussing chamber studies the equivalent short-circuit current inhibitable by amiloride (10 micromol/l) DMH-treated rats was about 40% of control. In addition, the hyperpolarizing effect of amiloride (10 micromol/l) on membrane voltage (Vm) was strongly attenuated in surface and mid-crypt cells of DMH-treated rats. Carbachol (CCH, 100 micromol/l), which predictably hyperpolarized surface, mid-crypt cells and crypt-base cells of control rats, had no significant effect on Vm in DMH-treated rats, but increased membrane conductance (Gm) significantly. This indicates that CCH probably activates both Cl- and K+ channels in all three colonic crypt compartments in the DMH-treated rats. Forskolin (5 micromol/l), which has the most pronounced effect in crypt-base cells in control rats, depolarized Vm and enhanced Gm in all three compartments in DMH-treated rats. These data indicate that DMH profoundly alters Na+ and Cl- transport in colonic crypts prior to the appearance of colonic adenocarcinoma and that these effects can be summarized as follows: (1) the Na+ conductance of surface cells is attenuated; (2) cells along the length of the crypt-lumen axis tend to lose their normal response to CCH and instead show simultaneous and comparable increases in K+and Cl- conductances; (3) the effect of forskolin is enhanced along the entire crypt axis. As a result colonic crypt transport is shifted to predominant Cl- secretion, findings which are characteristic of colonic carcinoma cell lines such as HT29 and T84 cells.

Mineralocorticoid receptors in the rabbit iris-ciliary body

To demonstrate the presence of mineralocorticoid receptors, specifically aldosterone receptors, iris-ciliary body cytosol from New Zealand albino rabbits was incubated with increasing amounts (0.5-20.0 nM) of radiolabeled aldosterone in the presence and absence of a 100-fold excess of aldosterone. A glucocorticoid receptor blocker, RU-28362, was employed when various steroids were allowed to compete with aldosterone for binding sites on the aldosterone receptor. Aldosterone bound to two classes of receptor proteins. Scatchard analysis of the data indicated one component to bind aldosterone with high affinity (Kd = 2.2 x 10-9 M) and low capacity (Bmax = 32 fmol/mg protein). If the concentration of aldosterone is increased, it also binds to a second component, but with a lower affinity (Kd = 9.8 x 10-9 M) and greater capacity (Bmax = 64 fmol/mg protein).

Evaluation of an algorithm for integrated management of childhood illness in an area of Kenya with high malaria transmission

In 1993, the World Health Organization completed the development of a draft algorithm for the integrated management of childhood illness (IMCI), which deals with acute respiratory infections, diarrhoea, malaria, measles, ear infections, malnutrition, and immunization status. The present study compares the performance of a minimally trained health worker to make a correct diagnosis using the draft IMCI algorithm with that of a fully trained paediatrician who had laboratory and radiological support. During the 14-month study period, 1795 children aged between 2 months and 5 years were enrolled from the outpatient paediatric clinic of Siaya District Hospital in western Kenya; 48% were female and the median age was 13 months. Fever, cough and diarrhoea were the most common chief complaints presented by 907 (51%), 395 (22%), and 199 (11%) of the children, respectively; 86% of the chief complaints were directly addressed by the IMCI algorithm. A total of 1210 children (67%) had Plasmodium falciparum infection and 1432 (80%) met the WHO definition for anaemia (haemoglobin < 11 g/dl). The sensitivities and specificities for classification of illness by the health worker using the IMCI algorithm compared to diagnosis by the physician were: pneumonia (97% sensitivity, 49% specificity); dehydration in children with diarrhoea (51%, 98%); malaria (100%, 0%); ear problem (98%, 2%); nutritional status (96%, 66%); and need for referral (42%, 94%). Detection of fever by laying a hand on the forehead was both sensitive and specific (91%, 77%). There was substantial clinical overlap between pneumonia and malaria (n = 895), and between malaria and malnutrition (n = 811). Based on the initial analysis of these data, some changes were made in the IMCI algorithm. This study provides important technical validation of the IMCI algorithm, but the performance of health workers should be monitored during the early part of their IMCI training.

A multicenter trial of FK506 (tacrolimus) therapy in refractory acute renal allograft rejection. A report of the Tacrolimus Kidney Transplantation Rescue Study Group

A multicenter trial was conducted to evaluate the efficacy and safety of tacrolimus in the treatment of refractory renal allograft rejection. Renal transplant recipients experiencing biopsy-proven recurrent acute allograft rejection were eligible if the current rejection episode was refractory to corticosteroids. A total of 73 patients were enrolled, of whom 59 (81%) had previously received at least one course of antilymphocyte antibody as rejection therapy. One-year follow-up was available in 93% of patients. Median time to tacrolimus rescue therapy was 75 days after transplantation (range, 18-1448 days). Therapeutic responses to tacrolimus included improvement in 78% of patients, stabilization in 11%, and progressive deterioration in 11%. The risk of experiencing progressive deterioration was related to the pretacrolimus serum creatinine level: serum creatinine < or = mg/dl, 3%; 3.1-5 mg/dl, 16% (P < 0.04); > 5 mg/dl, 23% (P < 0.02). Twelve-month (from the time of initiation of tacrolimus therapy) actuarial patient and graft survival rates were 93% and 75%. Graft loss occurred in 19 patients (25%) at a median time of 108 days. Fourteen episodes of recurrent rejection were diagnosed in 10 patients (14%), at a median time of 101 days. Eleven episodes of recurrent rejection were treated (three patients underwent transplant nephrectomy), with resolution achieved in nine patients. Antilymphocyte antibody therapy was not used to treat recurrent rejection. Serum creatinine values improved during tacrolimus therapy: median serum creatinine level before tacrolimus, 3.2 mg/dl; median at 1 year after tacrolimus, 1.8 mg/dl. Twelve infections were documented in 11 patients (15%), including cytomegalovirus infection in three patients (4%). Posttransplant lymphoproliferative disorder was diagnosed in a single patient. Tacrolimus whole blood levels averaged 15.0 +/- 9.9 ng/ml at day 7 of tacrolimus therapy and 9.4 +/- 5.1 ng/ml at 1 year, and were consistent among individual centers. Treatment outcome did not correlate with tacrolimus blood levels. The most commonly observed adverse events were neurological and gastrointestinal. Seventy-four percent of patients received tacrolimus for at least 1 year. Tacrolimus therapy was discontinued in 18% of patients for rejection (11% for progressive, unrelenting rejection, and 7% for recurrent rejection). Tacrolimus therapy was discontinued in 8% of patients due to adverse events. In conclusion, tacrolimus rescue therapy provides (1) prompt, effective reversal of refractory renal allograft rejection, (2) good long-term renal allograft function, (3) a low incidence of recurrent rejection, and (4) an acceptable safety profile in renal allograft recipients experiencing refractory rejection.

Invasive group A streptococcal infections in Ontario, Canada. Ontario Group A Streptococcal Study Group

BACKGROUND

Several reports suggest that the incidence of invasive group A streptococcal infections, including streptococcal toxic shock syndrome and necrotizing fasciitis, is increasing.

METHODS

During 1992 and 1993 we conducted prospective, population-based surveillance of invasive group A streptococcal disease in Ontario, Canada. We reviewed clinical and laboratory records, searched for secondary cases of invasive disease, and cultured specimens from household contacts.

RESULTS

We identified 323 patients with invasive group A streptococcal infections, for an annual incidence of 1.5 cases per 100,000 population. The rates were highest in young children and the elderly. Fifty-six percent of the patients had underlying chronic illness. Risk factors for disease included infection with the human immunodeficiency virus, cancer, diabetes, alcohol abuse, and chickenpox. The most common clinical presentations were soft-tissue infection (48 percent), bacteremia with no septic focus (14 percent), and pneumonia (11 percent). Necrotizing fasciitis occurred in 6 percent of patients, and toxic shock in 13 percent. The mortality rate was 15 percent overall, but it was 29 percent among those over 64 years of age (P<0.001) and 81 percent among those with toxic shock (P<0.001). Fourteen percent of the cases were nosocomial, and 4 percent occurred in nursing home residents, often in association with disease outbreaks. Invasive disease occurred in 2 household contacts of patients with infection, for an estimated risk of 3.2 per 1000 household contacts (95 percent confidence interval, 0.39 to 12 per 1000).

CONCLUSIONS

The elderly and those with underlying medical conditions are at greatest risk for invasive group A streptococcal disease, toxic shock, and necrotizing fasciitis. Invasive steptococcal infection is associated with a substantial risk of transmission in households and health care institutions.

Risk factors for carriage of drug-resistant Streptococcus pneumoniae among children in Memphis, Tennessee

OBJECTIVES

To determine risk factors for carriage of drug-resistant Streptococcus pneumoniae to understand better the factors promoting spread of these isolates.

STUDY DESIGN

We obtained medical and demographic information and nasopharyngeal swab specimens from 216 children less than 6 years old with upper respiratory tract infections, seeking medical care at five Memphis, Tenn, study sites. We evaluated risk factors for carriage of penicillin-nonsusceptible S. pneumoniae (NSSP) among 100 children with S. pneumoniae isolates. Patterns of antimicrobial prescription were recorded for enrolled children.

RESULTS

Independent risk factors for carriage of NSSP included an increased number of antimicrobial treatment courses during the previous 3 months and white race. Day care attendance approached statistical significance (p = 0.07). Most children with upper respiratory tract infection received a prescription for antimicrobial drugs. These prescriptions were more common for white children than for black children.

CONCLUSIONS

Increased use of antimicrobial drugs enhances the risk of carriage of NSSP. This may contribute to the higher risk among white children of NSSP infection; however, after control for antimicrobial use, white children were still at an increased risk of infection with NSSP, possibly through greater exposure to resistant strains.

Gene transfer by naked DNA into adult mouse brain

Nonviral gene transfer into the central nervous system could provide a basis for therapeutic uses and fundamental research. We show that naked DNA injected intracerebrally into the mouse brain can provide expression of a reporter protein. Expression is dose dependent, being maximal for 150 mu g DNA injected. We observed less than 5 days expression of the luciferase transgene, which is not improved with plasmid preparations virtually free of lipopolysaccharide. Thus, the adult brain behaves as striated muscle for naked DNA uptake and transcription, albeit at a much lower efficiency. In neither adult brain nor muscle did complexation of DNA with cationic lipid improve transgene expression. Double immunolabeling using cell-specific markers shows that both neurons and glia are transfected by naked DNA gene transfer methodology.

Cerebral aneurysm thrombosis, shrinkage, then disappearance after subarachnoid hemorrhage

The case is presented of a 37-year-old man with spontaneous thrombosis of a 10-mm left posterior communicating artery aneurysm, following presumed subarachnoid hemorrhage with negative angiography. Sequential magnetic resonance angiography and magnetic resonance source imaging (at 2 weeks, 3 months, 2 years, and 2 years, 5 months) showed progressive shrinkage and disappearance of the aneurysm.

A role of transforming growth factor-beta 1 in the control of corneal neovascularization

Transforming growth factor beta 1 (TGF-beta 1) has been implicated in both the stimulation of angiogenesis in vivo and in the inhibition of endothelial cell proliferation in vitro systems. In this study we present evidence showing that under certain experimental conditions TGF-beta 1 may inhibit neovascularization in vivo. TGF-beta 1 was incorporated into ethylene vinyl acetate copolymer (Elvax 40) matrixes which provide a valuable vehicle for the controlled and sustained delivery of bioactive peptides. The biological effectiveness of TGF-beta 1 sequestered in polymer matrices was assessed by measuring the inhibition of [3H]-thymidine incorporation into the DNA of cultured mink lung epithelial cells. Neovascularization was induced in both corneas of albino rabbits by one deep-seated limbal silk suture. Elvax 40 matrixes loaded with TGF-beta 1 (release rate, 1.66 ng/24 h) were implanted in rabbit corneal stroma. "Empty" polymers in the contralateral eye served as controls. Aliquots of aqueous fluid were withdrawn, and the presence activity of phagocytic cells was assessed by the production of superoxide anion (O2) which was measured by the superoxide dismutase-inhibitable reduction of ferricytochrome C. Polymer-enclosed TGF-beta 1 implanted in rabbit corneas significantly suppressed angiogenesis (2.65 +/- 0.4 mm compared to 3.05 +/- 0.3 mm in contralateral controls p < 0.05). Superoxide production in 100 microliters aliquots of aqueous fluid was 0.95 +/- 0.18 and 0.6 +/- 0.18 nmol O2/10 min in control eyes and in the eyes bearing sequestered TGF-beta 1, respectively (p < 0.02). These results indicate that under the experimental conditions selected in this study, TGF-beta 1 significantly suppressed in vivo angiogenesis.

The ion conductances of colonic crypts from dexamethasone-treated rats

Whole-cell patch-clamp studies were performed in isolated colonic crypts of rats pretreated with dexamethasone (6 mg/kg subcutaneously on 3 days consecutively prior to the experiment). The cells were divided into three categories according to their position along the crypt axis: surface cells (s.c.); mid-crypt cells (m.c.) and crypt base cells (b.c.). The zero-current membrane voltage (Vm) was -56 +/- 2 mV in s.c (n = 34); -76 +/- 2 mV in m.c. (n = 47); and -87 +/- 1 mV in b.c. (n = 87). The whole-cell conductance (Gm) was similar (8-12 nS) in all three types of cells. A fractional K+ conductance accounting for 29-67% of Gm was present in all cell types. A Na+ conductance was demonstrable in s.c. by the hyperpolarizing effect on Vm of a low-Na+ (5 mmol/l) solution. In m.c. and b.c. the hyperpolarizing effect was much smaller, albeit significant. Amiloride had a concentration-dependent hyperpolarizing effect on Vm in m.c. and even more so in s.c.. It reduced Gm by approximately 12%. The dissociation constant (KD) was around 0.2 micromol/l. Triamterene had a comparable but not additive effect (KD = 30 micromol/l, n = 14). Forskolin (10 micromol/l, in order to enhance cytosolic adenosine 3', 5'-cyclic monophosphate or cAMP) depolarized Vm in all three types of cells. The strongest effect was seen in b.c.. Gm was enhanced significantly in b.c. by 83% (forskolin) to 121% [8-(4-chlorophenylthio)cAMP]. The depolarization of Vm and increase in Gm was caused to large extent by an increase in Cl-conductance as shown by the effect of a reduction in bath Cl-concentration from 145 to 32 mmol/l. This manoeuvre hyperpolarized Vm under control conditions significantly by 6-9 mV in all three types of cells, whilst it depolarized Vm in the presence of forskolin in m.c. and in b.c.. These data indicate that s.c. of dexamethasone-treated rats possess mostly a K+ conductance and an amiloride- and triamterene-inhibitable Na+ conductance. m.c. and b.c. possess little or no Na+ conductance; their Vm is largely determined by a K+ conductance. Forskolin (via cAMP) augments the Cl- conductance of m.c. and b.c. but has only a slight effect on s.c.

Lipospermine-based gene transfer into the newborn mouse brain is optimized by a low lipospermine/DNA charge ratio

Nonviral, plasmid-based gene transfer into somatic tissues offers the prospect of various simple and safe therapeutic possibilities as well as applications in fundamental research. Although cationic lipids display efficient transfection activities in many in vitro systems, only low success rates using these vectors in vivo have been reported. We succeeded in defining conditions providing high levels of in vivo transfection in the brains of newborn mice. Our hypothesis was that conditions favorable for in vitro transfection (highly positively charged particles) were unlikely to be appropriate for in vivo conditions. When using the cationic lipid dioctadecylamido glycylspermine (Transfectam, DOGS) with a cytomegalovirus (CMV)-luciferase reporter gene, the best levels of transfection were obtained when using a low ratio of positive charges (supplied by the DOGS) to negative charges (carried by the DNA). Moreover, addition of the neutral lipid dioleoylphosphatidyl ethanolamine (DOPE) significantly enhanced transfection. Expression of the transgene diminished over time, independently of lipopolysaccharide content of the plasmid preparation used. This suggests that either a mitotic population of cells was preferentially transfected, or that promoter silencing was occurring. Histological examination of the spatial distribution of a beta-galactosidase-expressing transgene showed numerous groups of transfected cells both within the striatal parenchyma and in the paraventricular area. Thus, DNA-lipid complexes bearing overall charges close to neutrality open promising possibilities for modulating gene expression in the developing central nervous system and for therapy in the brain.

Comparison of M and T type antigen testing to field inversion gel electrophoresis in the differentiation of strains of group A streptococcus

Recent clusters of patients with acute rheumatic fever and invasive group A Streptococcus (GAS) have stimulated renewed interest in the epidemiology of streptococcal infections. We compared conventional serotyping for M and T antigens and serum opacity factor with field inversion gel electrophoresis (FIGE) for distinguishing among GAS. Fifteen pairs of throat isolates obtained from children positive for GAS before and after therapy were evaluated by conventional serotyping and by FIGE after SmaI digestion. Ten of the 15 pairs were identical by serotyping. FIGE correctly identified the 10 concordant and 5 discordant pairs. Individual clones were identified within each M type tested, including analysis performed on additional isolates of M1 and M3 obtained from the Centers for Disease Control and Prevention. This preliminary experience suggests that FIGE can successfully determine whether serial isolates from a given patient represent persistence of one strain or acquisition of a new strain of GAS and that this method might provide an alternative typing system for GAS.

Optic nerve head circulation in untreated ocular hypertension

AIMS

The laser Doppler technique was used to compare the capillary blood speed measured at localised sites of the optic nerve head in stable, untreated ocular hypertensive patients with that measured in healthy normal subjects. The stereophotogrammetric technique was also used to measure the retinal nerve fibre layer thickness at the disc margin in the eyes of the patients.

METHODS

Doppler broadening measurements were made at superior and inferior temporal disc sites in 18 eyes of 10 ocular hypertensive patients and in 12 eyes of seven age and sex-matched normal subjects.

RESULTS

On average, Doppler broadening and, hence, capillary blood speed were significantly higher (p = 0.018) in the patients than in the normal subjects. The largest values of Doppler broadening in the patients were measured at sites adjacent to the thinnest retinal nerve fibre layer. Linear regression analysis showed a significant inverse relation (p = 0.0004) between Doppler broadening and nerve fibre layer thickness in left eyes, and a nearly significant relation (p = 0.06) in right eyes. At temporal sites of the optic nerve head there is a compensatory relation between a thinning nerve fibre layer and a locally increasing blood supply to the optic nerve head.

CONCLUSION

Together with previous observations of fluorescein filling defects in similar patients, these results indicate that there is spatial heterogeneity of blood flow in the optic nerve head in stable, untreated ocular hypertensive patients.

alpha-Fluoro acid and alpha-fluoro amide analogs of acetyl-CoA as inhibitors of citrate synthase: effect of pKa matching on binding affinity and hydrogen bond length

An alpha-fluoro acid analog and an alpha-fluoro amide analog of acetyl-CoA have been synthesized. The ternary complexes of these inhibitors with oxaloacetate and citrate synthase have been crystallized and their structures analyzed at 1.7 A resolution. The structures are similar to those reported for the corresponding non-fluorinated analogs (Usher et al., 1994), with all forming unusually short hydrogen bonds to Asp 375. The alpha-fluoro amide analog binds with an affinity 1.5-fold lower than that of a previously described amide analog lacking the alpha-fluoro group. The alpha-fluoro acid analog binds with a 50-fold decreased affinity relative to the corresponding unfluorinated analog. The binding affinities are consistent with increased strengths of hydrogen bonds to Asp 375 with closer matching of pKa values between hydrogen bond donors and acceptors. The results do not support any direct correlation between hydrogen bond strength and hydrogen bond length in enzyme-inhibitor complexes.